“Total” brake failure yesterday... accumulator pump motor CONFIRMED (1 Viewer)

[2000LX470]

(Continued from first post...)
At this point, I carefully dumped the old brake fluid from the reservoir into a bucket on my bench, and then set the MC assembly upside down in a clean pan. I placed some clear rags over the brake line ports to keep dirt out. I also laid some clean rags over the disconnected brake lines in the engine compartment.
Time to remove the motor.

• Step 8: There is a wire harness of two (2) wires connecting the pump motor to the ABS solenoid block. There is a rubber boot covering both connections. Peel this back off the ABS block side, and check for corrosion. Mine were very clean. Remove two (2) phillips head screws holding the two ring terminals. The position of the wires—red and blue—is critical, but the rubber boot is also directional, and it really only fits back on one way.

View attachment 2109761

• Step 9: The pump housing is connected to the pressure accumulator (which is the vertical, beer can looking thing next to the fluid reservoir. The motor is bolted to the pump housing with two (2) allen bolts. I think these were 3.5mm.
• Step 10: Once the bolts are removed, separate the motor from the pump housing. Mine was firmly stuck, and required a few light taps with a brass drift to get it unstuck. Once it starts to move, use a screwdriver to carefully pry the motor off. There is a thin paper gasket between the motor and pump. I understand this part is not available separately, so I carefully separated mine from the motor housing with a razor blade. There’s a lovejoy coupler between the pump shaft and the motor shaft. Be sure to remove this and set it aside so you don’t lose it.

View attachment 2109762

Now that the motor was out, I wanted to jumper it directly to see if it ran. Hooked it up to my battery and… IT SPUN! (What does this mean???) I started and stopped in 20 times, and 5 of those times, it wouldn’t restart without a good shake. This is suggesting that the commutator is worn. So, I decided to break open the housing a have a look.

(Edit: At this point, I also rotated the pump shaft with my fingers to feel for any resistance or binding. The pump shaft turned smoothly, so I am hopeful that there is no issue/blockage with the pump.)

• Step 11: There are two (2) more allen bolts holding the motor can to the base plate. There are the same size (but not interchangeable with) the bolts holding the motor to the pump housing. Remove these, and then carefully pry the can away from the base plate.

When you open the housing, you will see a coated metal gasket between the can and base plate. I carefully removed and set this aside for possible future use.

There is also a thin wave washer that sits between the upper rotor bearing and the housing can. This will probably fall out and stick to one of the stator magnets. Find it and set aside for possible future use.

Once opened, I saw that the brushes are about halfway worn down, and almost half of the circumference of the commutator was completely worn through the copper down to the plastic core.

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So, I reassembled the motor and took it to a forklift repair shop in St. Louis today to see if they can rebuild it. The owner is pretty confident that he can source the necessary parts and turn around the rebuild in a few days (apparently, this is a very similar motor to the power steering motor that Japanese forklifts use). Eurton Electric is always a back-up, but I will see if I can get it rebuilt locally first.

While the MC assembly is out, I will probably replace the three rubber grommets between the fluid reservoir and the MC as a preventative measure. I may also rebuild the MC, but I wasn’t having any of the symptoms typical to an MC rebuild, so I am thinker better leave well enough alone (unless there is a good reason to go ahead and rebuild).

Thanks again for all the advice so far! I will continue to post updates as they come.

First of all, excellent post! I am having the same issue with my '99 LX. I have a feeling I will experience a similar issue when my MC is removed. Also, I found 47950-60010 Toyota OEM Genuine ACCUMULATOR ASSY, BRAKE BOOSTER for $220 (S/H included) from UAE. I am guessing this is the same piece you had the shop in St. Louis fix for you.

 

[MissouriLC]

First of all, excellent post! I am having the same issue with my '99 LX. I have a feeling I will experience a similar issue when my MC is removed. Also, I found 47950-60010 Toyota OEM Genuine ACCUMULATOR ASSY, BRAKE BOOSTER for $220 (S/H included) from UAE. I am guessing this is the same piece you had the shop in St. Louis fix for you.

Thanks! I hope it helps some folks out.

The part you are referencing is the pressure accumulator assembly. It screws on to the top of the pump. It's basically a two-chamber cylinder, with the chambers separated by a rubber diaphragm. The top chamber is sealed and filled with nitrogen, and the bottom chamber is is what the brake fluid is pumped into. The brake fluid presses against the nitrogen-charged diaphragm until a set pressure (measured by a sensor) is achieved. This is what provides the pressure boost for the brakes.

So far, my pressure accumulator appears to be okay. I had the pump motor rebuilt. The pump motor is not available from Toyota as a separate part. You can buy the motor and pump together (P/N 47960-60010, which McGeorge shows for $1,153.61), or you can by the motor and pump and accumulator together (P/N 47070-60010, which McGeorge shows for $765.82--less money for more parts!)

To my knowledge, neither the actual pump nor the accumulator are in any way serviceable.

 

[LXPearl]

Excellent post and the various trials and descriptions add value. The only comment I have is that I close the bleeder valve when the flow starts to slow and before it stops - to prevent a back flow of air. With a clear drain tube, air moving upward is a clue to close the bleeder. Thanks for all the information!

 

[2000LX470]

Thanks! I hope it helps some folks out.

The part you are referencing is the pressure accumulator assembly. It screws on to the top of the pump. It's basically a two-chamber cylinder, with the chambers separated by a rubber diaphragm. The top chamber is sealed and filled with nitrogen, and the bottom chamber is is what the brake fluid is pumped into. The brake fluid presses against the nitrogen-charged diaphragm until a set pressure (measured by a sensor) is achieved. This is what provides the pressure boost for the brakes.

So far, my pressure accumulator appears to be okay. I had the pump motor rebuilt. The pump motor is not available from Toyota as a separate part. You can buy the motor and pump together (P/N 47960-60010, which McGeorge shows for $1,153.61), or you can by the motor and pump and accumulator together (P/N 47070-60010, which McGeorge shows for $765.82--less money for more parts!)

To my knowledge, neither the actual pump nor the accumulator are in any way serviceable.

Thank you, brother! I have dedicated this weekend to work on the MC. This is the second time I have taken it out. Last time I installed a plunger thinking that would solve my problem...it didn’t. So now I’m doing what you did.

 

[2000LX470]

Thanks! I hope it helps some folks out.

The part you are referencing is the pressure accumulator assembly. It screws on to the top of the pump. It's basically a two-chamber cylinder, with the chambers separated by a rubber diaphragm. The top chamber is sealed and filled with nitrogen, and the bottom chamber is is what the brake fluid is pumped into. The brake fluid presses against the nitrogen-charged diaphragm until a set pressure (measured by a sensor) is achieved. This is what provides the pressure boost for the brakes.

So far, my pressure accumulator appears to be okay. I had the pump motor rebuilt. The pump motor is not available from Toyota as a separate part. You can buy the motor and pump together (P/N 47960-60010, which McGeorge shows for $1,153.61), or you can by the motor and pump and accumulator together (P/N 47070-60010, which McGeorge shows for $765.82--less money for more parts!)

To my knowledge, neither the actual pump nor the accumulator are in any way serviceable.

Also, you can buy the motor separately...

98 99 00 01 02 Land cruiser LX470 abs brake unit master cylinder booster motor | eBay

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[MissouriLC]

Also, you can buy the motor separately...

98 99 00 01 02 Land cruiser LX470 abs brake unit master cylinder booster motor | eBay

Find many great new & used options and get the best deals for 98 99 00 01 02 Land cruiser LX470 abs brake unit master cylinder booster motor at the best online prices at eBay! Free shipping for many products!

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Awesome! Good to know!

 

[2000LX470]

Awesome! Good to know!

I was able to finally get everything installed on my LX today. Had my wife help with the bleeding process. I tried bleeding earlier too but only did it twice per tire so I had to go back and do at least 4-5 times per wheel. All that to say, it’s firm now and the brakes are working like they should.
Here’s what’s interesting about my rebuild. So I found this guy who sells “new” motors on eBay for a number of Toyota SUVs. The one for Land Cruisers and LX’s he charges $350. For 4runners he charges $250. I noticed how the 4Runner and LX seemed very much the same based on the pictures. I ended up purchasing the one for a 4Runner. Needless to say, the 4Runner motor is about 1/2 inch smaller than the LX. I decided to go ahead and install it anyhow. I had to made mods to the bracket so that it would fit. Low and behold it’s on there and seems to be working fine (knock on wood). Now it’s a matter of time how long it’ll last. I do have the original motor which I intend to rebuild just in case.

 

[MissouriLC]

I was able to finally get everything installed on my LX today. Had my wife help with the bleeding process. I tried bleeding earlier too but only did it twice per tire so I had to go back and do at least 4-5 times per wheel. All that to say, it’s firm now and the brakes are working like they should.
Here’s what’s interesting about my rebuild. So I found this guy who sells “new” motors on eBay for a number of Toyota SUVs. The one for Land Cruisers and LX’s he charges $350. For 4runners he charges $250. I noticed how the 4Runner and LX seemed very much the same based on the pictures. I ended up purchasing the one for a 4Runner. Needless to say, the 4Runner motor is about 1/2 inch smaller than the LX. I decided to go ahead and install it anyhow. I had to made mods to the bracket so that it would fit. Low and behold it’s on there and seems to be working fine (knock on wood). Now it’s a matter of time how long it’ll last. I do have the original motor which I intend to rebuild just in case.

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Nice work!

I will also be interested to know how the smaller motor hold so up over time.

Before I dug into it, I was really DREADING doing this job. It was not so hard, though, and luckily my wife and I have a third car, so having the Cruiser off the road for a week while I worked on it was no big deal.

Given the stakes of failure, I don’t see a good reason NOT to pull the MC and inspect the motor at least every 90k or so, or as part of a base lining. I wish shops, even the independents, didn’t just default to replacing the whole assembly for $4K.

 

[2000LX470]

Nice work!

I will also be interested to know how the smaller motor hold so up over time.

Before I dug into it, I was really DREADING doing this job. It was not so hard, though, and luckily my wife and I have a third car, so having the Cruiser off the road for a week while I worked on it was no big deal.

Given the stakes of failure, I don’t see a good reason NOT to pull the MC and inspect the motor at least every 90k or so, or as part of a base lining. I wish shops, even the independents, didn’t just default to replacing the whole assembly for $4K.

Yes, I am with you on that. We have 4 vehicles total: my wife’s 2000 LX, my 1997 Cummins, my 2014 Versa Note and then this 1999 LX. I have been very curious though as I was working on this project: Would a cheaper motor that you can easily find on eBay work instead of spending hundreds of dollars on an OEM one? I mean everything internally looks identical to the one that’s installed on our MCs. Just a thought.

 

[2000LX470]

These are the motors I saw on eBay for a lot cheaper than what I paid for mine...not an electrician so maybe other factors need to be considered (i.e. RPMs).

 

[2000LX470]

Also, I wouldn’t be surprised if some of the Mitsubishi motors are identical to the Toyota motors... also much cheaper. Here are some YouTube vids I found useful:

 

[JunkCrzr89]

@2000LX470 Thanks for posting those links!

 

[luke lillie]

I experienced a “total” break failure in my ‘00 Cruiser yesterday. I’ve had the truck since January. During the first couple of weeks of ownership, I got the ABS/TRAC/Brake lights on the dash with the alarm... always on a cold morning first start. It would typically go away after 30 to 40 seconds. It did this maybe 8 to 10 time total and then stopped doing it for 8 months, until yesterday. I got the warning multiple times at start up, and then while driving in the afternoon, the lights and alarm came on and I lost most of my braking power. Having read the various threads on this, I knew what to expect. Luckily my office is only 10 minutes from home, and I was able to carefully drive home, using a combo a 2nd and 1st gear engine braking, the hand brake, and HARD pressure on the brake pedal.

I am fairly confident that the issue is a failed accumulator pump motor. While diagnosing last night, here’s what I was able to determine:

1. With the key in the ON position, “ABSMTR1” and “ABSMTR2” relays in the main fuse box open and close every 10 seconds or so.
2. The pump motor makes an electric, buzzing or humming sounds, but placing my hand under the MC on the pump and motor, I feel no vibration from the pump. (Edit: This may not have been the pump making this sound... I don't know.)
3. I tapped the pump repeatedly with a wrench, and it MIGHT have run for a second or so (I heard a momentary, loud vibration or grinding sound), but that was it. (Edit: In hindsight, I do not think that it ever ran.)
4. No pressure is being built in the accumulator. The fluid in the reservoir is up at the FULL line and does not change (does not drop to indicate fluid being pumped into the accumulator).

It sounds to me like the pump is stalled and not spinning. Occam’s razor would suggest that the motor itself is shot. I suppose it’s possible that the pump itself is clogged or seized. The system has no leaks, no double-pump pedal symptoms, and seemed to be working perfectly until yesterday.

(UPDATE 1)
Thanks, 2001LC, for the diagnostics advice. Here’s what I was able to accomplish last night:

• Before for proceeding with any further disassembly, I conducted the diagnostics that 200LC referenced form the FSM. First is to apply 12 v to the specified pins on the ABS solenoid block connectors. There are two large blades/pins in the center of the upper-left connector—one on top of the other. Connect the top blade to positive, the bottom blade to negative, and the motor should spin. I did this, and the motor DID NOT spin.

View attachment 2109681

• Next step, per the FSM, is the check the resistance of the circuit through the ABS block and the motor. On the same connector, there are three small pins to the left of the aforementioned power pins, arranged vertically. You measure the resistance between the middle pin and the bottom pin. It should measure between 30 and 36 ohms. Mine measured 33.0 ohms. Perfect!
• Next step, per the FSM, is to troubleshoot the ABS/VSC light circuit in the ECU harness. I opted not to do this, because the lights are clearly not false alarms. Results from the first two tests suggested to me that the ABS solenoid block circuit is good, and the motor has a good connection, so the problem must be internal to the motor. Time to pull the MC assembly
  (Note: I followed Skiddoo’s excellent how-to on the rebuilding the MC to guide me through removing this.)
• Step 1: Disassemble the driver’s side lower dash under the steering wheel. You will have to:
  • Remove the dead pedal (mine pulled straight out easily), pry up the front end of the plastic door sill trim, and pop off the kick panel (plastic clips only, no screws.
  • Pull the weatherstripping away from the front lower half of the door jamb.
  • Carefully pop off the black plastic trim strip below the instrument cluster (clips only).
  • Remove one (1) phillips screw from the lower left side of the dash trim panel, below the hood and gas filler door release levers.
  • Remove two (2) screws each from the hood and gas filler door release levers. These are hidden when the levers are in their “neutral” position. Carefully push the levers through the trim panel to the inside.
  • Working around the perimeter, carefully pry the trim panel off. There are an number of plastic clips, all of which release easily.
  • Remove the metal panel behind the plastic trim piece with four (4) 10mm bolts.
  • The ABS computer is mounted directly left of the steering column. Remove two (2) 10mm bolts, unhook the electrical connectors, and set the ABS computer aside (you’ll need a long extension and perhaps a U-joint to access these bolts.

View attachment 2109682

• Step 2: Unbolt the MC from inside the firewall. There are four (4) bolts, located in a rectangle around the MC plunger rod (connected to the top of the brake pedal). I did not remove the “crotch vent” HVAC duct, which made the bolts slightly harder to access, but still very doable. You need a 12mm deep-well socket.

View attachment 2109683

• Step 3: Remove the cotter pin and clevis pin connecting the brake pedal to the MC plunger rod clevis.
• Step 4: Move the charcoal canister in the engine bay. There is one (1) 10mm bolt holding the charcoal canister to the bracket that mounts it to the inner fender. It is located near the top, front edge of the charcoal canister. On the lower, front edge of the canister, toward the engine, there is a rubber hose with no hose clamp. Carefully remove this hose. Unhook the two (2) electrical connectors on top of the canister, and the pull the canister UP and out of the bracket. Mine required a good, hard pull, so much so that I thought I might have missed a bolt. Once out of the bracket, carefully move the charcoal canister to the open space between the fuse box and the engine cover.

View attachment 2109756

• Step 5: I not already done, unhook all the electrical connectors from the MC assembly. There are three (3) on the ABS solenoid block (facing the inner fender); one (1) up high near the reservoir (fluid level sensor); and one (1) below the fluid level sensor (pressure sensor).
• Step 6: Unscrew the flare nuts for the four (4) brake lines. Place some rags or paper towels to catch drips. Use a 10mm flare nut wrench. Mine were very easy to loosen (torqued to only 10 lb-ft or so). I would say that only about 1/4 oz of fluid leaked out.
• Step 7: This was the hardest part—wrestling the MC assembly out of the car. You need to pull it out and rotate it up and to the left (toward the left fender). It will want to get caught on the wiring, the detached brake lines, basically everything. Plus, the MC assembly is heavier than I anticipated, and it has to come pretty far forward for the plunger rod to clear the firewall. Just work back and forth, constantly moving the brake lines out of the way, and it will eventually come out.

View attachment 2109757

(Continued Below...)

What is the name of the red and white wiring

 

[2001LC]

The ~8" of wires with boots, going from bottom ABS units (black box of side of master) to booster motor. Is the brake control wire. Very pricy.