2001LC
SILVER Star
Are you using a flare nut wrench?
Master Cylinder Rebuild - DIY (3 Viewers)
- Thread starter Skidoo
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No, but thats a good idea to get more purchase. Thanks!
2001LC
SILVER Star
Flare nuts are only torqued in to 11Ft-lbf assumably, but can take much more to break loose. Additionally the flare nut itself is a soft metal. So it's best to use only flare nut wrench to break all loose.
It's also advisable to torque to spec and only nudge a little tighter if leaking. You'll see picture of corwsfoot flare nut socket I used to torque here: Installing SS Braided Brake lines, Flare nut stuck in pipe!
It's also advisable to torque to spec and only nudge a little tighter if leaking. You'll see picture of corwsfoot flare nut socket I used to torque here: Installing SS Braided Brake lines, Flare nut stuck in pipe!
I promise you i only hand snugged them. I am wondering if there is so much lateral pressure on them from the master cyl/abs assembly and the line that it puts additional pressure on the fitting over time and sort of 'tightens' it?
Thats a nice idea you have there. Maybe I will have to try to replicate it.
2001LC
SILVER Star
Most Shop's just replace hard lines when they've a bad flare nut.I promise you i only hand snugged them. I am wondering if there is so much lateral pressure on them from the master cyl/abs assembly and the line that it puts additional pressure on the fitting over time and sort of 'tightens' it?
Thats a nice idea you have there. Maybe I will have to try to replicate it.
Also worth mentioning is FSM suggest oiling threads on fuel filter flare nut when installing. FSM doesn't say same for brake line flare nut, but I make sure very clean and will add a drop of oil if dry (often wet with brake fluid). FSM has two different torques. 11ft-lbf, and 10ft-lbf if using SST with 30" fulcrum which is basically the tooling setup I show so 10ft-lbf. Oiled we need to reduce torque by 20% form the 10ft-lbf which brings us to say 8ft-lbf wet with SST. Then we've issue with accuracy of the torque wrench of choice/size/budget. So always start with light torque, work up higher if necessary 1ft-lbf at a time.
And yes, flare nut can and will hang-up/bind on hard pipe making spinning difficult if dry and not aligned well through nut.
Also flare end often mushroomed. I use a file or emery cloth (sandpaper) held against used flare of flare nut that has mushroomed, spinning flare nut to round out against file and take down a bit. That mushroom will otherwise hang up in threads of master or flex line.
But if one threads on by hand (no wrench at all) it can not be cross threaded, unless bionic fingers
.BTW: Releasing clips that hold the lines to body/frame sometimes make easier job of threading.
Most Shop's just replace hard lines when they've a bad flare nut.
Also worth mentioning is FSM suggest oiling threads on fuel filter flare nut when installing. FSM doesn't say same for brake line flare nut, but I make sure very clean and will add a drop of oil if dry (often wet with brake fluid). FSM has two different torques. 11ft-lbf, and 10ft-lbf if using SST with 30" fulcrum which is basically the tooling setup I show so 10ft-lbf. Oiled we need to reduce torque by 20% form the 10ft-lbf which brings us to say 8ft-lbf wet with SST. Then we've issue with accuracy of the torque wrench of choice/size/budget. So always start with light torque, work up higher if necessary 1ft-lbf at a time.
And yes, flare nut can and will hang-up/bind on hard pipe making spinning difficult if dry and not aligned well through nut.
Also flare end often mushroomed. I use a file or emery cloth (sandpaper) held against used flare of flare nut that has mushroomed, spinning flare nut to round out against file and take down a bit. That mushroom will otherwise hang up in threads of master or flex line.
But if one threads on by hand (no wrench at all) it can not be cross threaded, unless bionic fingers
BTW: Releasing clips that hold the lines to body/frame sometimes make easier job of threading.
Awesome info, thank you!
I unbolted the ABS system first. Do you think that is causing me problems?
I'll have to look for a replacement hard line part number. Is that a PITA to replace?
2001LC
SILVER Star
UnBolting Master/ABS assembly first is not a problem, unless you tried to remove and kinked a line (they bend easy and not a big deal to bend back).
If your issue is with flare nut being mushrooming flare tip, as I show in link I gave you. You can try rounding down as I, Slee and most shop do. Just take care to keep metal files or sandpaper grit out of line. Line must be flushed by disconnected at each end if your not very careful.
If flare to far gone, yes get a new hard line, they aren't that costly. Difficulty to replace will DEPEND ON WHICH line.
Any Toyota/Lexus Dealer will have PN # and your part.
Or you'll find this sight hefull for PN # and digarms even pictures of some parts www.partsouq.com
If your issue is with flare nut being mushrooming flare tip, as I show in link I gave you. You can try rounding down as I, Slee and most shop do. Just take care to keep metal files or sandpaper grit out of line. Line must be flushed by disconnected at each end if your not very careful.
If flare to far gone, yes get a new hard line, they aren't that costly. Difficulty to replace will DEPEND ON WHICH line.
Any Toyota/Lexus Dealer will have PN # and your part.
Or you'll find this sight hefull for PN # and digarms even pictures of some parts www.partsouq.com
Thanks! Sorry if that came off as a passive way to ask you for the P/N, that wasn't my intention. I can find it fairly easily when I'm not at work (our IT guys love to block every site under the sun).
If you are looking at the truck from the front, it's the line on the front of the abs unit, on the left. I'll get a part number and let you know, I'm curious if it's one you find tough to deal with, in your experience... Of course I might see the diagram and know right away, haha!
I think it is part number for the brake line is 44551-60010, but it is hard to tell. That is part 44551C on the diagrams I am seeing.
Being that this is all to try to diagnose a leak, I am hoping I need grommets as well and it fixes the issue. For anyone's future reference the part numbers I am finding are:
-47255-16010 (2x)
-31417-35010
Some of the part places are saying the 31417 part isn't for our trucks, so I will confirm and update the thread.
Being that this is all to try to diagnose a leak, I am hoping I need grommets as well and it fixes the issue. For anyone's future reference the part numbers I am finding are:
-47255-16010 (2x)
-31417-35010
Some of the part places are saying the 31417 part isn't for our trucks, so I will confirm and update the thread.
2001LC
SILVER Star
I've no idea which line that is, or have I had unusual issue with it.
I've not had issue with any factory flare nut on master being mushroomed. But sure sometimes they're difficult to get lined up just right to get threads started and threaded by hand. I just really take my time and get comfortable when doing these. I don't want to get flustered and put a wrench on and force.
I'd hold off buying until you've back out the flare nut and see what's what. .
2001LC
SILVER Star
@ton504 the picture(s) of ABS I posted above is from a 98-99. You can see more here of a 98. Ball joint & ABS unit replacement plus stuff.. on 98LC W/151K
In 2000 Mr. T added following so the ABS unit is different.
I think (I'll be watching closer for this to make sure) one of the main difference we can see in 00-07 the addition of this pressure sensor. Perhaps someone with 98-99 can confirm
I'll add, if you hear the booster pump running every few minutes with IG (key) on. This could indicate a pressure loss. This is something I'm going to pay closer attention too. As it may be normal to hear this occasionally, but to often may indicate a leak or air in system. So testing booster/accumulator would be a good idea in this event, by evacuating accumulator (key off pump brake pedal 40 times) then time how long booster runs once IG turned on. Spec is 30 to 40 seconds.
2007 Brake Master/ABS assembly
In 2000 Mr. T added following so the ABS unit is different.
- VSC (Vehicle Skid Control) added
- A-TRAC (Active Traction Control) added
- EBD (Electronic Brake Force Distribution) added
I think (I'll be watching closer for this to make sure) one of the main difference we can see in 00-07 the addition of this pressure sensor. Perhaps someone with 98-99 can confirm
I'll add, if you hear the booster pump running every few minutes with IG (key) on. This could indicate a pressure loss. This is something I'm going to pay closer attention too. As it may be normal to hear this occasionally, but to often may indicate a leak or air in system. So testing booster/accumulator would be a good idea in this event, by evacuating accumulator (key off pump brake pedal 40 times) then time how long booster runs once IG turned on. Spec is 30 to 40 seconds.
2007 Brake Master/ABS assembly
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2001LC
SILVER Star
I
Look in the link I provided, it may be there. But that is off a 98.
@2001LC , I borrowed your photo below. I was wondering what was on the other side of the plastic housing which the electronics were in but I realized it's probably just ports.
Do you still have this one available for some testing? Or anyone else with a faulty ABS unit that is willing to separate the plastic portion and send it to me for some testing? I'll pay for shipping both ways. To be clear, I just need the plastic portion with the electronics or the "brain" of the ABS unit.
Do you still have this one available for some testing? Or anyone else with a faulty ABS unit that is willing to separate the plastic portion and send it to me for some testing? I'll pay for shipping both ways. To be clear, I just need the plastic portion with the electronics or the "brain" of the ABS unit.
2001LC
SILVER Star
I was interested in following the leads (two screws at bottom) for the booster pump power, back up into plastic. I was looking for possible leak from inside plastic to leads into bottom of wire boot. What I found was the plastic is molded around leads and to coils protruding from aluminium block. I smashed plastic to bits, to separate from aluminum block. My conclusion was it was near, if not totally impossible for a leak to occur at this point.
@2001LC Thanks again for the pictures. Now I need to get my hands on one so I can check out the pressure switches thats next to the solenoids.
I believe the high pressure switch is causing the squealing and squawking noise some of us hear on cold starts. My theory is that when the booster motor spins the pump, it doesn't get feedback from the high pressure switch to stop the motor/pump and typically happens when its cold out. The noise is from some sort of pressure relief valve thats built into the pump itself since the fluid can be seen dumping back into the master cylinder reservoir via the rubber feed hose.
For the members who experienced the squealing or squawking noise and kept the old unit after replacement, I would love to check it out. I only need the side with the molded plastic and can be removed by the 6 bolts.
I believe the high pressure switch is causing the squealing and squawking noise some of us hear on cold starts. My theory is that when the booster motor spins the pump, it doesn't get feedback from the high pressure switch to stop the motor/pump and typically happens when its cold out. The noise is from some sort of pressure relief valve thats built into the pump itself since the fluid can be seen dumping back into the master cylinder reservoir via the rubber feed hose.
For the members who experienced the squealing or squawking noise and kept the old unit after replacement, I would love to check it out. I only need the side with the molded plastic and can be removed by the 6 bolts.
2001LC
SILVER Star
You're welcome.
I've not had this noise issue, so can't offer much help.
First test is look at color of fluid, it darkens as moisture content goes up.
Than I check fluid level and booster run time after evacuating accumulator.
Next is to look at accumulator to make sure side are not touching bumpers in cage.
Using a stethoscope at time of squawking noise may be revealing.
If your correct and issue is in ABS unit, nothing can be done short of replacement. So are you looking at swapping out your ABS?
I've not had this noise issue, so can't offer much help.
First test is look at color of fluid, it darkens as moisture content goes up.
Than I check fluid level and booster run time after evacuating accumulator.
Next is to look at accumulator to make sure side are not touching bumpers in cage.
Using a stethoscope at time of squawking noise may be revealing.
If your correct and issue is in ABS unit, nothing can be done short of replacement. So are you looking at swapping out your ABS?
- Thread starter
- #218
Another big difference for 00-07 is a separate brake line to each wheel from the MC, pre 2000 only 3 lines to MC as both rear brakes were on same line.
OK so I pulled the entire unit after getting a flare nut wrench (thanks @2001LC!).
There are no leaks from it all, from what I can see. I also cannot find a leak from any brake lines anywhere on any brake lines I trace, nor is there any wet spots on any calipers.
But I losing fluid out of what should be a closed system... What the hell? Anyone have any ideas?
There are no leaks from it all, from what I can see. I also cannot find a leak from any brake lines anywhere on any brake lines I trace, nor is there any wet spots on any calipers.
But I losing fluid out of what should be a closed system... What the hell? Anyone have any ideas?
2001LC
SILVER Star
Without me going back and reading your post. Why do you think fluid is leaking if you've not found a wet spot.
Two things to keep in mind:
Two things to keep in mind:
- Look for leaks with key on and someone pressing brakes pedal down hard, or just after hard braking drive.
- Too check level in reservoir; turn IG (key) off, pump pedal 40 times. (Just opening hood and looking level will vary each time)
