Master Cylinder Rebuild - DIY (1 Viewer)

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Great write up and post Cliff! Its been added to my list of 'to do-s'.
 
The FSM makes reference to Special Service Tools. However I didn't see the used in this write-up. One for diconnecting the brake lines (BR-50). And another for removing the brake accuator tube no. 1 (BR-52). Are the nuts accessible using other tools?
 
Think I just used a metric flare nut wrench. I have a set of Harbor Freight metric swivel flare nut crowfoot 3/8 drive, might of used them. Don't see them in their online catalog. But did not use SSTs.
 
Sorry for the double post, had meant to post this pic in Skidoo's thread.

Anyway I pulled the MC out and swapped the piston from the rebuild kit. Process is smooth albeit a bit messy.

Found this small crack in one of the rings on the piston. Hoping this was the cause of the failure and tomorrow once I get the MC reinstalled and the brakes bled all will be right in the world!
image-2077414855.jpg
 
That was probably your problem. My o-rings seemed a bit loose when I did the MC plunger swap. Good job diving into that. :clap:



Sorry for the double post, had meant to post this pic in Skidoo's thread.

Anyway I pulled the MC out and swapped the piston from the rebuild kit. Process is smooth albeit a bit messy.

Found this small crack in one of the rings on the piston. Hoping this was the cause of the failure and tomorrow once I get the MC reinstalled and the brakes bled all will be right in the world!
 
Sorry for the double post, had meant to post this pic in Skidoo's thread.

Anyway I pulled the MC out and swapped the piston from the rebuild kit. Process is smooth albeit a bit messy.

Found this small crack in one of the rings on the piston. Hoping this was the cause of the failure and tomorrow once I get the MC reinstalled and the brakes bled all will be right in the world!

Nice fix! Better than $1800, eh?
 
Bled the fronts no problem, however I can't seem to get anything flowing from the rear bleed valves (tried for quite a while). And when I start it up during the bleed process I'm still getting the ABS and brake warning lights and buzzer. Maybe I'm missing something?
 
Bleed rears with key on or engine running. You will get bells and lights until you finish. Double check booster pump is running, if not check that ALL the electrical connections are hooked back up.
 
Just overhauled my MC: Thanks Skidoo for a great DIY thread!

I will add: You can only get about 50% of the brake fluid removed from the reservoir before removing the whole assembly from the rig: Turkey baster or not. But not to worry as 99.9% of the fluid is held in the MC system, assuming you don't actuate the plunger after you get the brake lines disconnected ;), until you get the assembly removed. Then you can turn it upside down to get most of the brake fluid out of the reservoir. The remaining fluid, as Skidoo tells us above, will come out when you pull the reservoir from the MC body and ditto again for when you pull the plunger out of the MC.

Plunger removal note: You have to give the plunger a pretty good tug to get it out...

The white ring was missing on my piston/plunger altogether. Don't know where it could have gone but I guess it was not installed at the factory on the first go around; weird. EDIT: UPON CLEANING THE PARTS WASHER OUT I FOUND THE WHITE RING IN THE BOTTOM OF THE TANK. Not quite sure how it jumped off the original piston but solves the mystery anyway :)

The piston/plunger was "notchy" and not at all smooth before I removed it from the MC. I was fearing the worst: Scored and/or corroded aluminum cylinder walls. But upon thorough cleaning and inspection the cylinder walls look perfect.

I swapped the old for the new piston/plunger complete with the white plastic sealing ring in place and the action is velvety smooth. I can only hope this and the remaining overhaul of my brake system will address the pedal symptoms I've experienced since taking ownership of this rig 6-1/2 years ago.

BTW: The plastic sealing ring is supposed to have that splice in it...that's the only way it could be installed onto the piston.

Sorry for the crappy photo...old on top new on bottom.
99 LC MC plunger compare new & old.jpg
 
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Anxious to hear your results. Let us know how it turned out.
 
Anxious to hear your results. Let us know how it turned out.

Its going to be a couple weeks as I started two more projects on the rig that just couldn't wait. More to come.
 
Hello Mudmates,

I am fixing to do this rebuild in a day or so. I don't have a FSM and need guidance from others that have done this repair on torque values and any other pertinent info to help make this a success. Also types of brake fluid etc is helpful as well. Got the lit from C-Dan for $49 and change. It arrived this morning

Thanks in advance

TLC Dan
 
Hello Mudmates,

I am fixing to do this rebuild in a day or so. I don't have a FSM and need guidance from others that have done this repair on torque values and any other pertinent info to help make this a success. Also types of brake fluid etc is helpful as well. Got the lit from C-Dan for $49 and change. It arrived this morning

Thanks in advance

TLC Dan


DOT 3 or 4 is what you want for brake fluid. There are IIRC only 7 nuts/bolts you deal with: The 4 nuts that retain the MC to the firewall, the 2 nuts that retain the ABS ECU to the MC, the piston end bracket nut and the 1 bolt to remove the charcoal canister from the fender mount. That and the philips head screws that retain the MC fluid reservoir to the MC. Nothing that is torque wrench critical unless you plan to use a cheater bar and/or 1/2" drive breaker bar ;)
 
Another successfully rebuilt master cylinder......

Getting the plunger out took a huge tug! I almost took the whole MS apart per the FSM (So i was instructed) but it finally gave in:)

It took a few blocks for the squeel and the ABS and Brake lights to go out. Had me sweating bullits for a while.

All is well with my LX...


Horay!!!!!!!!

TLC Dan
 
I forgot to give credit where credit is due.......

Thanks Skidoo !!!!!!!!

Wouldn't have wanted to do it without your detailed write up. No shop around would touch rebuilding a MS for liability reasons. You saved me a bunch of $$$$$$$$$$$$$$ This allows me to take the fam to the oregon coast for a end of summer beach weekend.

This forum is the bomb!!!!!!!

Tlc Dan
 
This thread is great - my issues is a loss of pressure - I have to stand on the breaks to stop while both the ABS and Brake lights are on. I was hoping it was due to poor o-rings on my MC piston so I ordered the rebuild kit and installed it as detailed on this thread. Now my pump is not coming on but it was when I started the process.

Do you suppose it could be the relay? When I turn the key on I can hear the relay click, the 5 secs or so it clicks off. Then it just repeats. Before I pulled the MC it would do this but my pump motor would go on for the time in between clicks - around 5 seconds or so. It would come on then it would go off, come on , then it would go off?

Is this normal? Could I have a bad relay? Could it be a bad pressure switch? Toyota wants $77 for the relay - I am going to check with Autozone.

Any and all advise is greatly appreciated.

Here in Atlanta,

Dave
 
UPdate - couldn't get it to work - the pump motor would not come on when the relay switched on. Removed again and bench tested with a 12V battery and motor works. Must be a sensor.

Got frustrated and took it to my dealer - asked them to trouble shoot.

They came back with "needs complete booster pump assembly" so I got them to match and online price of $1,800 and jsut over $350 in labor to install.

Done and back on the road.
 
UPdate - couldn't get it to work - the pump motor would not come on when the relay switched on. Removed again and bench tested with a 12V battery and motor works. Must be a sensor.

Got frustrated and took it to my dealer - asked them to trouble shoot.

They came back with "needs complete booster pump assembly" so I got them to match and online price of $1,800 and jsut over $350 in labor to install.

Done and back on the road.
Thanks for sharing.
Just to clarify:
The booster worked when removed from the truck, but not when in place?
You changed the complete booster with new part, and everything was OK?
 

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