“Total” brake failure yesterday... accumulator pump motor CONFIRMED (2 Viewers)

[MissouriLC]

My brakes look great but!!! here is mine .. what should I do .. 2001 at 150 k miles

Time for preventative maintenance . ??


View attachment 2110992

I would respectfully add to 2001LC's response... while you've got it out, you might as well detach and open the motor case to verify your brush and commutator wear. If heavily grooved, there's little value in reinstalling without a rebuild.

 

[katit]

I'm getting anxious now. Every other time I brake I hear whine. From brake pump. Should I start worrying?

 

[2001LC]

Well "whine" not good. I'd take a closer look!

 

[katit]

Well "whine" not good. I'd take a closer look!

Not whine but I hear it. Like "bzzzss". Louder than AHC pump for sure

 

[MissouriLC]

(Update: continued from Post #5)

As mentioned above, I dropped the booster pump motor off at a local forklift motor rebuilder on Thursday last week (October 17). They looked it over and were fairly confident that they could source the correct commutator and brushes. I got the call on Friday, October 18 that the commutator and brushes were ordered--to arrive on Monday, October 21--and that they would be rewinding the armature, for a total of $190 out the door. It should be ready on Wednesday, October 23!

I also ordered the following parts from McGeorge Toyota:

47547-12030	Plug Bleeder (4)
31478-30010	Cap Bleeder Plug (4)
04493-60330	Master Cylinder Repair Kit (1)
47255-16010	Reservoir Assembly Grommet (2)
31417-35010	Grommet (1)

This is to complete the MC rebuild/reconditioning. Plus, I have no idea what condition my bleeders are in, so... might as well!

This weekend, while waiting for parts, I made some progress on disassembling/cleaning the MC:

• Step 12: Remove and clean the MC reservoir. First, release the plastic clip that holds the connector for the reservoir fill level sensor from the metal bracket on the MC as the front of the reservoir. There are three (3) phillips screws securing the reservoir to the MC--two in the back (vertical), and one in the front (horizontal). Gently lift the reservoir off the MC, and remove the three (3) rubber grommets (two of main remained stuck in the MC). I am replacing these, but if you're reusing, clean them thoroughly and set aside. Per Skiddoo's instructions, clean the reservoir with denatured alcohol. Pour out any remaining brake fluid, plug the ports in the bottom with paper towels, and fill halfway with alcohol. Put on the cap and shake it around, and then let sit for 5 minutes or so. Unplug the ports, and drain out the alcohol. Repeat two or three times. There will probably be some black deposits in the bottom of the reservoir, which is what we're trying to remove. Once the alcohol runs clean and you can see that the deposits are gone (or mostly gone), shake out any remaining alcohol and set aside with the cap off to dry. While doing this, I also thoroughly cleaned the exterior of the reservoir with denatured alcohol. Cleaned reservoir is shown below.
  
  
  
  
  
  
  
  
• Step 13: Now, I decided to go ahead and pull the MC plunger in prep for the rebuild kit. To do this, set the MC assembly on its side, resting on the ABS solenoid block. Then:
  • Remove the clevis from the plunger rod. Place a screwdriver though the holes in the clevis, and put a 14mm flare nut wrench on the clevis lock nut. Holding the plunger rod stationary with the flare nut wrench, use the screwdriver to rotate the clevis counter-clockwise (I'll post a picture of this later, but it is makes sense once you start). Mine took a good deal of force to break loose. Once loose, thread the clevis and lock nut off the plunger rod.
  • Pry the rubber boot off the MC and slide off the plunger rod.
  • At this point, you will see the rear portion of the plunger assembly, with the rod protruding, in the rear of the MC bore. There is a lock ring that keeps this in place. To access the lock ring, you need to push the silver-colored, rear portion of the plunger assembly into the bore. I slipped a deep-well 22mm socket over the plunger rod, seated on the rear portion of the plunger, and pushed firmly. I did not need to use a hammer, and the rear portion of the plunger moved down in the bore about 3/16 of an inch.
  • To remove the lock ring, there is a hole in the side of the MC (the right hand side, when the MC assembly is sitting on the ABS block) where you can insert a pin to push the lock ring in enough to grab it with a pick. This hole is in the groove that secures the rubber boot. My lock ring's gap was over the hole, so I needed to gently rotate the lock ring with a large flathead screwdriver. You want to be pushing on the very end of the lock ring, next to the gap.
  • Use a pin, nail, or something to push the lock ring through this hole (I used a small allen key). You only have to push it 1/8 inch or so... just enough to carefully grab the end of the lock ring with a hooked pick. Be careful not to gouge the aluminum MC, and pop the ring out.
  • Last part is to pull the plunger. Thread the clevis back on the rod, and use the screwdriver through the clevis holes to pull the plunger straight out. When I first tried this, I just pulled with steady force—as hard as I could—, and I couldn't get it to pull out more than about 1/8 inch. Then I figured out a trick. While firmly holding the MC flange (the part that mounts to the firewall), push the plunger in as far as you can (it is spring-loaded). Then, firmly and quickly yank straight back, using the spring tension to assist in popping the plunger out. I did this on my bench without any clamping, but securing the MC on a jig in a vise would have made it easier.

At this point, I am just waiting on parts! I will post updates as they occur.

 

[MissouriLC]

Alright... hit a bit of a snag. If anyone can offer some insight, I truly appreciate it.

Got home from some business travel yesterday (Friday) and all my parts were waiting for me. MC rebuild kit, reservoir grommets, new bleeder plugs, bleeder plug caps, and of course my rebuilt motor.

I was able to get everything assembled and reinstalled last night (I will post a more detailed step by step once this all gets figured out). I pre-bled the MC on the bench as best I could.

Today, I attempted to bleed the brakes. The system, as far as I can tell, is bled--at least from the MC to the calipers. However, the system is not building pressure properly. After discharging the pressure accumulator (40 pumps, key off), the pump runs for about 70 to 75 secs before pressure is fully built. In addition, every press of the brake pedal triggers the pump to run for about 10 sec. Sounds plenty strong running, no strange noises. Also, brake pedal is super solid--not that it was bad before, but now its noticeably better.

Before the motor failed, I would say my vehicle acted normally, as compared to others. Built pressure in about 35 sec, pump would kick on for 4 to 5 sec after every third of so brake pedal depression.

Also, the system seems to be HOLDING pressure fine (I am still testing this), but not building pressure within spec. Therefore, I think there might be air trapped in the pressure accumulator. What do I do about this?

The FSM makes this cryptic statement on page BR-4:
"HINT:
If the hydraulic brake booster has been disassembled, disconnect
the brake line from the hydraulic brake booster or if the reservoir
becomes empty, bleed the hydraulic brake booster."

Does that mean the red coated line connected from the pressure accumulator to the MC?

My first thought was to crack that flare nut and let the pump run to see if air is pumped out (have to re-bleed the brakes afterward, obviously). However, I can't see another way to even check if there is air in the accumulator, and the FSM is kind of vague.

What say you? Thanks!

 

[2001LC]

First check battery voltage. The greater the voltage, the faster the motor/pump spins. 12.5v or better is perfect. The same motor, may take 52 sec at 11.5v, but achieve 32 sec run time at 12.5V.

I find, when we've no fluid in master, like a new one. It takes extra bleeding of accumulator. At first, we'll not much fluid draws down from reservoir, after accumulator evacuated (IG key off, pump 40 times) when IG key turned on. Keep repeating, key off pumping pedal, IG key on (bleeding accumulator. Then flush/bleed from a rear bleeder, until no air in fluid. I like to get air from rear bleeders first, as they're easy. As we only need open a rear bleed while IG key on an brake pedal held down. Often I'll repeat bleeding accumulator a few times, before bleeding fronts. It's important to not let reservoir below min line, especially as we move to bleeding the fronts.

I do like to rear bleed after activating ABS or I air bleed in tech stream. This is incase any air in valves of ABS, had remained.

If still long run times.

Either leak or air in the systems or both, is most common reason for the 70 second run time. Although 70 is much more than I every get.

One issue I find with long run times, after flushed and bled the systems. Is a leak at one or more bleeders, usual rear ones. More of weep than a leak really, and very hard to detect. Usually I see motor run time from 45 to 50 seconds max with these weeps. OEM bleeders is only ones I use in OEM calipers. If not OEM caliper it can be difficult to match replacement bleeders. Leading cause weep, is rust in caliper at seat of bleeder. This is due to not keeping bleeder's capped. Those little rubber $2.00 caps, missing. Can result in rendering useless, a $250 caliper (rear).

It is also possible you've issue with the install of new master plunger. Like plunger seal leaking, it's very hard to see as boot hides outer seal leak. If you can't find any bleeders weeping. I then pull boot of master plunger and look for wetness in boot.

Brake fluid in small amount (not pooling) dries up quick. So actively use brakes, and press hard on brake peddle just before inspecting for leaks.

You can use a de-greaser and water hose or a can of brake fluid cleaner, to clean wet spots on calipers or master. Then inspect for leak, like at flare nut threads. You need all rubber caps off when inspecting the bleeders. Leaks can be just a tiny weep. So you must have dry to detect a weep, and I mean 100 % dry.

Bleed/flush.
The way I start the flushing, is at rear wheel DS. Rear because, I only need brake peddle held down and IG key on any can run out a lot of fluid easily. DS, because it is close to area I'm working in. Per FSM, run pump no longer than ~120 seconds. Once I've no air in my DS line. I move to PS rear. I know there is no air, by watching my clear bleeder hose. Once rear done I move to PS front. Now I need a help to pump peddle 20 time with IG key on. After first 20 peddle pump, helper only need pump 5 times. Helper, holds down peddle as I open then close bleed. Never let off peddle with a bleeder open, fronts or rears.

Now if you like you can bleed by starting up front as FSM states. While TS air bleeding. Or drive on dirt or icy road stomp on brakes at 20 to 30 MPH, to activating ABS systems. I do this a minimum of three times. Go back to shop and check air and leaks for leaks again.

I do not install bleeder caps until all is good and I've blown out bleeders with brake cleaner and high pressure air. I want those bleeders dry or brake fluid as I can get them internally. I'll add a few drops of DW40, then cap them.

Some notes:

1. When flare nuts, are difficult to thread back on: I use just tiny drop of oil on flare nut threads and on pipe (not in flared end) where ii passes through flare nut, to aid in threading them back on master by hand. I'm supper careful, to not get any oil on flare, in line or master. Lubed threads means, torque may be as much as 20% high than torque wench set/reads. So I go very easy on torque, as I may be over-torque. Lube threads may get to 9.6Ft-lbf with Torque wrench set to 8ft-lbf. I use a inch foot pound torque wrench set to 96in-lbf, to increase accuracy.
2. Supper careful not cross threads and keep pipe free from binding as I seat flare in very squarely, by gently pulling out on pipe, as I thread flare nut in. Last thing we want is to damage flare or threads.
3. I keep reservoir above low line.
4. I only use a flare nut wrench or crows foot flare nut type socket to remove and torque on to the 8ft-lbf flares and bleeders. I will increase torque on a weeping bleeder up to ~11ft-lb max. If still weeping after that, I replace.
5. I've had a few booster motor during test, that ran 43 to 45 seconds. That I spent 8 hours looking for leak, not finding. Brakes worked fine, but time ran just a little over the 40 sec (~43 sec). This just corrected itself after driving a day or two. DUH, weak battery.

With clear hose it easy to see air bubbles or lack of.

Some note:

 

[2001LC]

A thought that just came to mind. You may have had a leak that been going on for a long time. A sign of this would be needed to top brake fluid from time to time. More than pad wear would normally require.

I so often find, when wire bad commutator bad. I'm not and electrical engineer. But from what I've been reading, the higher resistance from a bad wire cause higher heat in motor. This high heat causes copper to wear faster. Yet your wire was fine
This may indicates higher heat in motor due to long and/or excessive runs times.

I noticed the bottom of your pump was wet in picture you posted after pulling master. I assumed this was just spillage from removing master. If that was wet before any spillage. You may have a pump seal leak in in that area.

Some other signs of a leak at pump "may" be seen under master area. Brake fluid is hard on paint. If you find it was oily on inner fender, before removal or paint damage.

If leaking you should find some signs now. Again the key to finding leaks. Is area must be 100 % clean and dry. Then activate brake system and inspect.

 

[MissouriLC]

A thought that just came to mind. You may have had a leak that been going on for a long time. A sign of this would be needed to top brake fluid from time to time. More than pad wear would normally require.

I so often find, when wire bad commutator bad. I'm not and electrical engineer. But from what I've been reading, the higher resistance from a bad wire cause higher heat in motor. This high heat causes copper to wear faster. Yet your wire was fine
This may indicates higher heat in motor due to long and/or excessive runs times.

I noticed the bottom of your pump was wet in picture you posted after pulling master. I assumed this was just spillage from removing master. If that was wet before any spillage. You may have a pump seal leak in in that area.

Some other signs of a leak at pump "may" be seen under master area. Brake fluid is hard on paint. If you find it was oily on inner fender, before removal or paint damage.

If leaking you should find some signs now. Again the key to finding leaks. Is area must be 100 % clean and dry. Then activate brake system and inspect.

Hi, Paul: Super helpful info... thank you! Here’s what I did today:

• First, I checked all of the flare nuts and bleeder screws for leaks. I think I had a small seep at both the rear PS bleeder and the front DS flare nut at the MC. I tightened those, sprayed everything clean with brake cleaner, and did the 40 pump test twice. Both times, the pump ran for about 73 sec., but I observed no further leaks.
• I also examined all around MC on the inner fender, as well as the plunger seal. No wetness or leaks.
• Next, I decided to try and bleed the accumulator. I jumpered the pump directly to the battery while intermittently cracking the flare on the high pressure line at the accumulator. I bled a little air out, and then I continued to run the pump until the pressure relief valve burped back into the reservoir. I did this process three times, which may not have been necessary. After I got everything hooked back up, the pump ran for 57 to 58 seconds. Improvement!
• Finally, I bled the brakes exactly according to your instructions. Got some more air out, but not all of it I don’t think. Pump run time is now down to 50 sec.

So, it seems to be an issue with air in the system. Going to bleed them again tomorrow and see if I can get it straightened out. These are definitely trickier to bleed than what I am used to!

 

[2001LC]

Sometime these just go perfect and have perfect run test times. Sometimes a real PITA and very time consuming.

I've never tried bleeding accumulator at HP line. I don't like touch a fare nut anymore than I must.
Air should bleed itself out of pump, accumulator and HP line.

I'd:
Do multiple accumulator evacuation (IG key off, pump pedal 40 time)

If pedal good, brakes good go out and activate ABS on a hard braking drive.

Then start bleeding again.


Note: I do often take reservoir level to near empty with booster motor/pump. But that is just during first part of a flushing.

 

[MissouriLC]

Sometime these just go perfect and have perfect run test times. Sometimes a real PITA and very time consuming.

I've never tried bleeding accumulator at HP line. I don't like touch a fare nut anymore than I must.
Air should bleed itself out of pump, accumulator and HP line.

I'd:
Do multiple accumulator evacuation (IG key off, pump pedal 40 time)

If pedal good, brakes good go out and activate ABS on a hard braking drive.

Then start bleeding again.


Note: I do often take reservoir level to near empty with booster motor/pump. But that is just during first part of a flushing.

Couple of other notes, to answer some of your questions form earlier posts...

• I've never had to add brake fluid since I bought the truck 10 months ago... in fact, I don't think the fluid level has dropped at all for pad wear, at least not noticeably.
• The pump was definitely greasy/grimy when I first pulled the MC... there were no drips, but perhaps a little seepage? There was no brake fluid/greasiness/paint damage on the fender skirt under the MC. If I had to guess, it was coming from that low-pressure rubber hose connecting the pump back to the MC. I probably should have replaced that when I had it all apart... I will definitely keep an eye on that over the next few weeks.

I was also hesitant to bleed from the accumulator flare nut... and in hindsight, it probably wasn't necessary. What I do think WAS helpful was to the manually jumper the pump to the battery and run it to the point that the pressure relief valve started burping fluid back into the reservoir. Not sure if this was absolutely necessary, but it certainly got some air out.

Couple of questions for you...

• Rear calipers bleed easily... you crack the bleeders and get a full, strong stream of fluid through the bleeder tube, very easy to spot bubbles. It seems clear that the motor/pump PRIMARILY pressurizes the rear brakes. The front brakes, however, don't seem to produce enough fluid volume to even fill my 3/8 O.D. plastic bleeder tube. There is always an air bubble right near the bleeder, and it is tough to tell when the bubbles in the line stop. Is this normal? Or, indicative of more air in the system? How should it flow when bled?
• After activating the ABS, how much more air do you typically get out on the second bleed? My understanding is that air tends to collect in the ABS solenoids, and activating the ABS breaks up those bubbles and forces them into the lines, where they can be bled out.

This system is complicated! I am still not sure exactly how it works! But, working with it is giving my a better idea--much more so than simply reading about it!

 

[RobE30]

Thanks for documenting all of your work. If our new truck ends up needing this, I might offer my Toyota tech friend a nice dinner and or beer (after the job of course) to do this. I will be checking the wire connections on my next day off. Current issue is a leaking radiator from the top tank.

 

[2001LC]

Couple of other notes, to answer some of your questions form earlier posts...

• I've never had to add brake fluid since I bought the truck 10 months ago... in fact, I don't think the fluid level has dropped at all for pad wear, at least not noticeably.
• The pump was definitely greasy/grimy when I first pulled the MC... there were no drips, but perhaps a little seepage? There was no brake fluid/greasiness/paint damage on the fender skirt under the MC. If I had to guess, it was coming from that low-pressure rubber hose connecting the pump back to the MC. I probably should have replaced that when I had it all apart... I will definitely keep an eye on that over the next few weeks.

I was also hesitant to bleed from the accumulator flare nut... and in hindsight, it probably wasn't necessary. What I do think WAS helpful was to the manually jumper the pump to the battery and run it to the point that the pressure relief valve started burping fluid back into the reservoir. Not sure if this was absolutely necessary, but it certainly got some air out.

Couple of questions for you...

• Rear calipers bleed easily... you crack the bleeders and get a full, strong stream of fluid through the bleeder tube, very easy to spot bubbles. It seems clear that the motor/pump PRIMARILY pressurizes the rear brakes. The front brakes, however, don't seem to produce enough fluid volume to even fill my 3/8 O.D. plastic bleeder tube. There is always an air bubble right near the bleeder, and it is tough to tell when the bubbles in the line stop. Is this normal? Or, indicative of more air in the system? How should it flow when bled?
• After activating the ABS, how much more air do you typically get out on the second bleed? My understanding is that air tends to collect in the ABS solenoids, and activating the ABS breaks up those bubbles and forces them into the lines, where they can be bled out.

This system is complicated! I am still not sure exactly how it works! But, working with it is giving my a better idea--much more so than simply reading about it!

Yes, front brakes are a pain to bleed. But with my clear hose, fit very sung on bleeder. I get a solid stream once air out. The helper must not let off the pedal, until bleeder is closed. Bleeder is never opened unless pedal held down.
IG key on at all times.
It takes time get fronts bleed. First bleed always pump pedal 20 time on a front. Help then holds pedal down, then I open bleeder. After that first 20 pumps, helper can just pump 3 to 5 times each bleed. Helper should feel improvement in pedal at this point. Once I've no bubbles I keep bleeding ~7 to 10 times. Pedal should feel good to helper, each 7 to 10 times I bleed now. I Just get small amounts with each bleed. Very slow process. But helper should report pedal firmer/better as you go. My hose may be smaller IDK, but once air out, it's solid full of fluid, for at least 12 inches nearest bleeder.

FSM states, start at front. But I start at rear to clear the reservoir, master, accumulator, lines and caliper top end of old fluid and air. Rears are the long lines/pipes. After my hard brake drive, I may start at front and re-bleed. But if I feel I've air trap in master area, based on pedal feel. Or a really dirty system, I go back to rear. Rears we'd get fluid fast and easy by systems on it's own power. Fronts are a pain, slow and I need a helper. So I save fronts for last, and a final bleed. Final bleed is just going around from front to rear and drawing a small amount, provided pedal feels good. It's just a check really that can be passed up. But the front are first as FSM reads.

After my hard drive if pedal good, time test good and fluid wasn't to bad to start with. I may not bleed anymore. It's only and few OZ of old that may have now mixed with new from ABS. We've a lot of old fluid in the caliper, we can't get in a typical flush. The small amount from ABS isn't that concerning. But if pedal soft, time test long. Well, start where you like. You've more than likely got air. Air has likely moved and may be in all lines by then.

We may or may not have air in ABS unit on master. Most times I'm just trying to move fresh fluid through. Pedal feel is a clue. If I think ABS had air. I go back and run the rear lines first. As I'm going around again pulling fluid from all lines from the master to the bleeders.

I've use little 3, to as much as 8, 32 oz bottles.

I had one once, sat for a year with bad brake leak. Brake fluid was pump out a big leak and then brakes lost, than sat. Talk about hard to get air out. But it did come out. Rears no problem. But fronts a pain.

BTW: I believe this is in the 100 series FSM. I know I just saw in 200 series. A warring. Do not let booster pump run more than ... it was like 90 second IIRC. But I never go more than 20 seconds. That is only while I flushing the rear calipers. I get a lot out, in 20 seconds.

 

[MissouriLC]

Thanks for documenting all of your work. If our new truck ends up needing this, I might offer my Toyota tech friend a nice dinner and or beer (after the job of course) to do this. I will be checking the wire connections on my next day off. Current issue is a leaking radiator from the top tank.

Thanks, Rob! Once this is all sorted, I will try to do a more comprehensive step-by-step summary.

I am certainly no expert in this, and I've relied heavily on Paul's and Skiddoo's expertise. I tried to get a good handle on all this before starting, and I think I had a pretty good grasp, but the experience of actually doing it is invaluable! Hopefully this thread will help convey some of what I've learned to others.

I will say that, when buying and immediately after getting our 100, I was DREADING the potential of having to do this. Now that is done (or, hopefully, nearly done), I would say that pulling the MC, doing the plunger rebuild, and at least inspecting--if not reconditioning--the motor should be a baseline maintenance task like wheel bearings. Honestly, I've spent more hours flushing and bleeding the brake system than any other part of this job! If you are flushing and bleeding, it's only an additional 2-3 hours to pull and inspect the MC.

Nice E30 in your sig! Years ago I had a lovely gray '87 325 2-door (w/ the Eta engine). Great car! Mine was unfortunately totalled when I was rear-ended on the highway with 199,600 miles on the clock!

 

[MissouriLC]

Yes, front brakes are a pain to bleed. But with my clear hose, fit very sung on bleeder. I get a solid stream once air out. The helper must not let off the pedal, until bleeder is closed. Bleeder is never opened unless pedal held down.
IG key on at all times.
It takes time get fronts bleed. First bleed always pump pedal 20 time on a front. Help then holds pedal down, then I open bleeder. After that first 20 pumps, helper can just pump 3 to 5 times each bleed. Helper should feel improvement in pedal at this point. Once I've no bubbles I keep bleeding ~7 to 10 times. Pedal should feel good to helper, each 7 to 10 times I bleed now. I Just get small amounts with each bleed. Very slow process. But helper should report pedal freely better as you go. My hose may be smaller IDK, but once air out it solid full of fluid, for at least 12 inches nearest bleeder.

FSM states start at front. But I start at rear to clear the reservoir, master, accumulator, lines and caliper top end of old fluid and air. Rears are the long lines/pipes. After my hard brake drive, I may start at front and re-bleed. But if I feel I've air trap in master area, based on pedal feel. Or a really dirty system, I go back to rear. Rears we'd get fluid fast and easy by systems on own power. Fronts are a pain, slow and I need a helper. So I save fronts for last, and a final bleed. Final bleed is just going around from front to rear and drawing a small amount, provided pedal feels good. It's just a check really that can be passed up. But the front are first as FSM reads.

After my hard drive if pedal good, time test good and fluid wasn't to bad to start with. I may not bleed anymore. It's only and few OZ of old that may have now mixed with new from ABS. We've a lot of old fluid in the caliper, we can't get in a typical flush. The small amount from ABS isn't that concerning. But if pedal soft, time test long. Well start where you like. You've more than like got air. Air has likely moved and may be in all lines bey now.

We may or may not have air in ABS unit on master. Most times I'm just trying to move fresh fluid through. Pedal feel is a clue. If I think ABS had air. I go back and run the rear lines first. As I'me going around again pulling all the from master to bleeder.

I've use little 3, to as much as 8, 32 oz bottles.

I had one once sat for a year with bad brake leak. Brake fluid was pump out a big leak and then brakes lost. Talk about hard to get air out. But it did come out. Rears no problem. But fronts a pain.

BTW: I believe this is in the 100 series FSM. I know I just saw in 200 series. A warring. Do not let booster pump run more than ... it was like 90 second IIRC. But I never go more than 20 seconds. That is while only while flushing rear. I get a lot out in 20 seconds.

Thanks, Paul! This is really good info.

I've gone through 6 32 oz bottles so far!

From your description, I still need to bleed my fronts better. I just haven't done it enough yet.

Out of curiosity, do you bleed the rears w/o a helper? Can you do it w/o the brake pedal depressed? Just using the pump to push the fluid?

 

[2001LC]

Say Hello To MY Little Friend.. He's-a spring-a load-ed.. Formerly a shower curtain rod!

 

[MissouriLC]

Say Hello To MY Little Friend.. He's-a spring-a load-ed.. Formerly a shower curtain rod!
View attachment 2119519
View attachment 2119524

Brilliant!

 

[RobE30]

Thanks, Rob! Once this is all sorted, I will try to do a more comprehensive step-by-step summary.

I am certainly no expert in this, and I've relied heavily on Paul's and Skiddoo's expertise. I tried to get a good handle on all this before starting, and I think I had a pretty good grasp, but the experience of actually doing it is invaluable! Hopefully this thread will help convey some of what I've learned to others.

I will say that, when buying and immediately after getting our 100, I was DREADING the potential of having to do this. Now that is done (or, hopefully, nearly done), I would say that pulling the MC, doing the plunger rebuild, and at least inspecting--if not reconditioning--the motor should be a baseline maintenance task like wheel bearings. Honestly, I've spent more hours flushing and bleeding the brake system than any other part of this job! If you are flushing and bleeding, it's only an additional 2-3 hours to pull and inspect the MC.

Nice E30 in your sig! Years ago I had a lovely gray '87 325 2-door (w/ the Eta engine). Great car! Mine was unfortunately totalled when I was rear-ended on the highway with 199,600 miles on the clock!

Mine is also Delphin Grey, sadly faded, but still grey. I've had it almost 18 years and have put well over 100k on it. I love the car and hopefully will be painting it soon if I can find a spot to do so over the winter.

 

[MissouriLC]

(Update: Continued from post #25)

Finished!

First of all, massive thanks to Paul (2001LC) for his advice on the bleeding procedure. I watched several YouTube videos and read the FSM procedure a dozen times, and I wasn't having success. Paul's instructions in the posts above are spot and an invaluable. So, let me summarize step by step what's happened since my last update. I was trying to work quickly and was covered with brake fluid most of the time, so I was not taking photos.

I was traveling for work last week, awaiting my parts order and rebuilt motor. When I arrived home on Friday, I had a pile of parts waiting for me:

• From McGeorge Toyota, a MC rebuild kit; the three (3) MC reservoir grommets; four (4) new bleeder screws; and four (4) new bleeder screw caps.
• From the local motor repair shop, I picked up my rebuilt booster motor. They replaced the commutator, rewound and rebalanced the armature, installed new brushes, installed new bearings, cleaned up the case, and reassembled everything for $194 out the door.

(Note: Total parts cost was about $310, plus about $50 worth of new brake fluid--8 synthetic DOT 3 32 oz bottles.)

I had prepped everything before going out of town, so now I am ready to reassemble. On Friday evening, I put it all together.

• Step 14: Reassemble the MC. This was much easier than taking it apart!
  • First, I poured about half a cup of fresh brake fluid into the MC bore, let some run out of the holes, and dumped the rest out. This rinsed a little bit of dirt out of the bore.
  • Following Skiddoo's write-up, set the MC on it's end, with the open bore facing the ceiling. There is guide rod and spring captive at the bottom of the cylinder. Move or tap the MC gently to make sure the guide rod is standing mostly straight up. This inserts into the end of the plunger.
  • Then, carefully insert the plunger into the bore, getting it over that guide rod. I did this WITHOUT the silver rear plate of the plunger assembly on the rod, which makes things easier to see.
  • Once centered and inserted, slide the rear plate over the plunger rod, making sure the chamfered edge is facing OUT. Get it square to the bore, and push it in with firm pressure. You should be able to do this with your fingers only. If tempted to tap it in with a hammer, STOP, because it is not square with the bore.
  • Push the rear plate into the bore past the snap ring groove, and install the snap ring so that one end is just overlaping the hole to the push the snap ring out. Then, pull back on the plunger rod to seat the rear plate against the snap ring.
  • Install the dust boot, clevis, and lock nut (Note: I forgot to do this before putting the MC back in the car! Thus, I had to install it under the dash and use the pedal height spec in the FSM to set the distance--a pain in the ass!)
• Step 15: Install the motor. I reused the old paper gasket. First, make sure the vent hole on the PUMP is not plugged with grime. Put a light smear of grease of the mating surface of the pump, and place the gasket on (it only fits one way). Drop the lovejoy onto the motor shaft, insert the rubber bumper over the mounting pin on the motor bracket, and rotate the motor under the mating surface of the pump. Mate the pump and motor together--it might take a bit of fiddling to the make the drive shafts and lovejoy match up--and make sure the position of the gasket doesn't shift. When all lined up, hold the motor and pump together and install the two allen bolts. Reconnect the two-wire harness from the ABS block to the motor terminals, using dielectric grease under the rubber boots.
• Step 16: Install the reservoir. Make sure the ports on the top of the MC are clear, and install the grommets. Remember, they are two different sizes--the outside ones are larger, the center one is smaller. Rinse the inside of the reservoir with clean brake fluid, and set the reservoir in the grommets. Secure the reservoir with the three screws.
• Step 17: Bench bleed the MC. Fill the reservoir with fresh fluid and pump the plunger by hand 80 to 100 times. This will help get a lot of the air out of the MC.
• Step 18: Install the MC back into the car. This was actually easier than removing it. Installation is the reverse of removal, and just be careful of the various hard lines, hoses, and wires in the way. Install the four (4) firewall bolts, and then carefully reconnect the hard brake lines. If dry (mine were not), lube the flare nuts with brake fluid and thread them in by hand as far as they will go before putting a wrench on them. Torque to spec, reconnect wiring, and give everything on and around the MC a good spray down with brake cleaner.

(to be continued...)

 

[MissouriLC]

(Update: continued from post #39)

I completed Friday night's work by installing the new bleeder screws in the calipers. The old ones were quite crusty, and the fronts were clearly not OEM. The rear's are easy to access with the wheels still installed, but I was not able to get a wrench on the fronts with wheels on. So, I put the front of the truck on jack stands and removed the wheels. Now, I was all set up to start bleeding on Saturday.

• Step 19: With everything hooked up, I filled the reservoir to the MAX line and put the ignition to ON. The pump came on, along with the alarm and dashboard lights (Brake, ABS. VSC/TRAC). I wasn't really sure what to expect, as there was clearly a LOT of air in the system. The pump would run for about seven seconds, click off, and then click on again. It did this over and over for a LONG time--probably two minutes. All the time the alarm is on. At this point, I am convinced something is wrong. The fluid was clearly being slowly pumped out of the reservoir, but very slowly. At about two minutes, the alarm finally turned off. After another 20 to 30 seconds, the pump shut off, as pressure had been achieved.
  
  (I was a little concerned during this process, but in hindsight, I think the pump was just struggling to build pressure against so much air. Anyone else who has removed and serviced their MC, I would be interested to hear your experience with this.)

On Saturday morning, I enlisted the help of my 8 y/o daughter to push the pedal. Now, here is where I ran into a snag (as outlined in the real time posts above). Here's what I did: starting at the rear, I had my helper press the pedal five times, holding it down on the fifth. With a clear plastic tube attached to the bleeder screw, going into a sealed mason jar, I cracked the bleeder screw. The pump immediately kicked on, and a large amount of fluid flowed out easily. Lot's of old, dirty fluid, and air bubbles. It took repeating this process about four times per side to get the rears fully flushed and bled. I found so much fluid coming out that I had to top off the reservoir before every repeat. I think I went through 2 32 oz bottles doing the rears.

Then, I went to the fronts, using the same procedure. However, the front's proved VERY difficult. Where the rear bleeders produced a strong stream of fluid that completely filled the plastic tube, the fronts produced only a thin stream... and there was always a big air bubble right at the bleeder. So, I bled each side 9 or 10 times, using about another half-bottle of brake fluid. I didn't really see a change in what was coming out of the bleeders. Then, I noticed that the right rear bleeder had leaked...s***! So, I topped off the reservoir again and bled everything again. The fronts seemed liked they were bled, and the brake pedal felt very firm. Stupidly, I put the wheels back on, took it off the jack stands, and THEN did the pump run time test.

My first hint that something was wrong was when I pumped the accumulator down. The brake pedal was VERY hard for the first five or so pumps. Then, it had kind of a "two stage" feel--softer for the first half of travel, then firm. After 30 or so pumps, it would go straight to the floor. I put the key in and ran the pump--it ran for 1 minute, 17 seconds (77 sec) before shutting off.

On Paul's advice, I checked the MC plunger, every bleeder, and every flare nut for leaks. I found a little seepage at the left front brake line flare nut on the MC--otherwise, no leaks. So, I tightened that nut and cleaned everything with brake cleaner.

I was convinced, at this point, that there was a significant amount of air trapped in the pressure accumulator. So, I attempted to manually bleed this. I am not sure if this was necessary and, if I were doing this again, I would bleed the front brakes 100 times before attempting to the bleed the accumulator, but YMMV. This might help you if run into the same issue I did (it did help me), but I am not sure it is necessary.

• First, you have to disconnect the wire harness for the pump from under the ABS block with the whole MC installed... this is HUGE pain in the ass! You need a mirror and either an offset screwdriver or a phillips bit in a small ratchet handle (this is what ended up working for me. Carefully undo the screws, and be careful not to drop them! Disconnect the other plugs from the MC assembly.
• Hook you battery up to a battery tender (this is imperative, otherwise you will quickly deplete your battery). Connect some jumpers with alligator clips to the wire harness and to the battery terminals--red to red, and blue to black. Connect the alligator clips to the harness first, then connect the red to the + terminal on the battery, and then connect the blue to the - terminal on the battery. When you make this connection, the pump will start running.
• Let the pump run for about 45 seconds, and then crack the flare nut on the pressure accumulator where the twisty, red-clad hard high pressure line connects. You'll need layers of plastic bags, cardboard, and many paper towels or rags under this in the engine compartment to catch fluid. I got some hissing, sputtering air and then a steady flow of clean, fresh brake fluid. I the retightened the flare nut and shut the pump off by disconnecting it from the battery.
• Remove your rags, spray the hole area down with brake cleaner, and dry with clear paper towels. Then, pump the pressure accumulator down with the brake pedal--40 times. At this point, I noticed my brake pedal felt much better.
• Then, I re-jumpered the pump and let it run until the pressure relief valve started burping fluid back into the reservoir. The inlet is toward the front of the reservoir, making the air/fluid burp very easy to see. I got some bubbles for the first few seconds, and then just fluid. I disconnected the pump, reconnected the harness and all the ABS unit connectors, checked everything for leaks again, and then pumped the accumulator down. Then, I did the run-time test again. This time, the pump only ran for 56 to 58 seconds--not good, but better!

So, there was definately a lot of air in the accumulator, and this helped. However, I cannot say if it was necessary, and it was a little butt-puckering to actually do it. I'm therefore not going to RECOMMEND this as a procedure, but I want to outline what I did if you are also having trouble.

Finally, I followed Paul's bleeding procedure from above, which I will recap here. IMO, his is the only description that actually makes sense and is accurate. I used a helper for both the fronts and the backs.

• Step 20: Ignition key ON, helper in driver's seat, battery tender connected... connect your bleeder tube to the bleeder screw on the rear right caliper. Make sure reservoir is topped off, and have the helper depress the brake pedal and hold it down. Open the bleeder screw, and fluid will flow out (the pump will kick on). Let flow for about 10 to 15 seconds, checking for bubbles in the tube. Close the bleeder screw. Make sure your helper is still depressing the pedal, and repeat once more. If no air bubbles come out the second time, you are good to go. If bubbles are still coming out, keep repeating until no more bubbles appear. (Note: be careful not to run the reservoir below the MIN line. Mine pumped out about 4 oz of fluid every 10 seconds, so make sure you are keeping an eye on the reservoir and topping off as necessary.
• Step 21: Repeat on left rear caliper.
• Step 22: Top off the reservoir and move to the front.
  • Keeping the ignition ON, have the helper pump the brake pedal 20 times, holding it down on the last pump. Connect the bleeder tube to the bleeder screw on the front right caliper. Open the bleeder screw. Fluid should flow out, and the pedal should drop to the floor. Leave the bleeder open for 3 to 4 seconds, at which point fluid flow should slow and stop. Close bleeder screw, and have helper release the pedal (AFTER screw is closed)!
  • Have the helper pump the pedal 5 times, holding it down on the last pump. Repeat as above, making sure the pedal is not released until after the bleeder screw is closed.
  • As the brakes are bled, the volume of fluid in the hose will increase until the bleeder hose is fully filled with fluid, like the rears. You will still get some bubbles.
  • (Per Paul) When the bubbles stop, repeat this another 7 to 10 times! Every time you do it, have the helper report on the pedal feel. The pedal feel should improve with every repeat. (Note: Each repeat dispenses between 0.5 and 1 oz of fluid. So again, make sure you keep the reservoir topped off and between the MIN and MAX line.
• Step 23: Repeat on left front caliper.

For my fronts, it took me 10 times to bleed per caliper (no bubbles), and then I did 10 additional on each side. Then, I ran the pump run-time test again. It dropped from 57 seconds to 40 seconds! Success!

I cleaned everything up and checked for leaks. Finding none, a put everything back together--and changed spark plugs while I was at it!

What I still need to do is activate the ABS several times and then do a final bleed, but this will have to wait until this weekend. However, the pedal feel is normal (like it was before), with a consistent feel until 32 or 33 pumps with the key OFF. Also, the braking "strength" is noticeably improved. It was not bad before, but it is better now. The pump is also a lot quieter than it was before. Before, the sound was noticeable in the car when the pump ran. Now, I feel the vibration in the pedal, but I don't really hear it.

I've had no lights and no alarms either, even though the overnight temp was below freezing last night (this would typically trigger an alarm on start-up in the past.

So, for about 10 hours of labor (taking my time, and dicking around with the bleeding, not doing it right!) and less than $400, I seemed to have fixed the issue!

Hope this helps other who are facing the prospect of a $4000 MC assembly replacement. Cheers!