Fatal Design Flaw '01-'02 4Runner Brake Master Assembly $3k

[Mutant]

I have an '01 and I have always wondered how much it would cost to replace the master cylinder whenever I was doing work under the hood. I knew it wouldn't be cheap just the sheer complexity of its design but I would never have guessed it would be $3K.

I'm trying to wrap my head around that price, it's just so outlandish.

My truck has 242K and is due for a rear axle seal repair, power steering rack replacement and a fuel pump replacement. All of which are very expensive repairs as you all probably already know. I hope and pray this MC develops no issues because I just can't afford another repair at this point.

Thank you for sharing this information, Mutant.

I'm happy to help. This forum has helped me out a lot. Just want to return the favor.

I have another good condition Master Assembly for sale if anyone is interested. I bought a 2nd used unit as a backup because I needed my truck running ASAP. PM me if you would like to buy the other good assembly. 20lbs shipped from 79707. Paypal. $420 plus shipping. Good used unit. It is the entire assembly together.

I can also sell the bad Master Assembly if anyone wants particular parts off of it or wants to rebuild it. PM me.

 

[DK327]

My truck has 242K and is due for a rear axle seal repair, power steering rack replacement and a fuel pump replacement. All of which are very expensive repairs as you all probably already know.

My 00 is the same mileage... So all that's what I have to look forward to... Not fun! I'm also due for timing belt/water pump pretty soon as it was last replaced at 165K.

 

[TOY2G]

I'm happy to help. This forum has helped me out a lot. Just want to return the favor.

I have another good condition Master Assembly for sale if anyone is interested. I bought a 2nd used unit as a backup because I needed my truck running ASAP. PM me if you would like to buy the other good assembly. 20lbs shipped from 79707. Paypal. $420 plus shipping. Good used unit. It is the entire assembly together.

I can also sell the bad Master Assembly if anyone wants particular parts off of it or wants to rebuild it. PM me.

Did the repair go well?

I'm glad you brought this up, I had no idea this was a thing.

 

[Mutant]

Did the repair go well?

I'm glad you brought this up, I had no idea this was a thing.

Mechanic said it was fine other than the time consuming process of bleeding the master unit. Bleed...wait an hour.....bleed....wait an hour....bleed...wait...bleed.
Truck behaves normally now but brake pedal is spongy. Probably needs lines bled after the swap.

 

[TOY2G]

Mechanic said it was fine other than the time consuming process of bleeding the master unit. Bleed...wait an hour.....bleed....wait an hour....bleed...wait...bleed.
Truck behaves normally now but brake pedal is spongy. Probably needs lines bled after the swap.

That's odd, I just did the tundra brake upgrade on both of my 3rd gen and BOTH have spongy brakes even after bleeding all 4 wheels several times. I wonder if it has something to do with the MC.

 

[nissanh]

It is easy to bleed these systems. No need to wait for hours.

Even after replacing the master pump, you still need to bleed all 4 wheels.

Turn the ignition key to "ON" position and bleed as you normally would. Be careful not to keep the ignition at ON position for prolong periods as this can heat up the ignition coil packs.
Have someone to press and hold the brakes. I got my daughter to do the job. The motor runs and pretty much pushes out the fluid. Be ready to catch all that.

 

[jgue467]

Fatal flaw it is not.

While this part could be expensive; from reading here for several years I've seen little to zero mention of it as a "fatal flaw" much less just another problem. Really rare.

There are several other components that could cost thousands at a stealer like the engine, trans, rear end, a/c, front end, and on and on so this one item doesn't qualify IMOH as a "fatal flaw" just cuz of the cost.

A "fatal flaw" is developing sludge in an engine that is otherwise well maintened like the 2.0 4 cylinder and the 3.0 6 cylinder toyo made for many years in the 90s.

Luck to all.... :cowboy:

 

[SaulG]

https://www.ebay.com/p/?iid=282325380893&&&dispItem=1&chn=ps

Not so fatal merely a flesh wound.

 

[nevada]

That's odd, I just did the tundra brake upgrade on both of my 3rd gen and BOTH have spongy brakes even after bleeding all 4 wheels several times. I wonder if it has something to do with the MC.

the tundra calipers are larger, yes? then, yes if you don't also upsize the MC, you will have a soft pedal.

 

[Chim]

the tundra calipers are larger, yes? then, yes if you don't also upsize the MC, you will have a soft pedal.

This is not the case with mine.. I have an 02 with larger Tundra brakes and my pedal feels great with no MC up size. :noidea:

 

[JayRolla]

the tundra calipers are larger, yes? then, yes if you don't also upsize the MC, you will have a soft pedal.

I didnt have a soft pedal on my TBU. Lately is has gotten soft even after bleeding. I have found the brake booster is failing. If you put your rig in 4wd low and move 10 feet you should beable to get it to stop quickly. If the peddle is soft and then gets hard but you keep moving teh brake booster is most likely failing.

 

[01thunder]

This is not the case with mine.. I have an 02 with larger Tundra brakes and my pedal feels great with no MC up size. :noidea:

i have them on my 01 without issues.

 

[nevada]

This is not the case with mine.. I have an 02 with larger Tundra brakes and my pedal feels great with no MC up size. :noidea:

so the tundra calipers aren't bigger? then why do people use them? what is the advantage?

they are either bigger, or they aren't. but if they are, if the piston bore is bigger, you will need to adjust the MC bore accordingly, or you wont have the same feel at the pedal.

its physics.

 

[Chim]

so the tundra calipers aren't bigger? then why do people use them? what is the advantage?

they are either bigger, or they aren't. but if they are, if the piston bore is bigger, you will need to adjust the MC bore accordingly, or you wont have the same feel at the pedal.

its physics.

Yes, the calipers are bigger, and no I didnt adjust MC.. speaking of physics, my pedal feels great.. not sure what to tell you.

 

[jgue467]

so the tundra calipers aren't bigger? then why do people use them? what is the advantage?

See post #8 (and others on same page) for a side by side pic comparison and related info, that'll make up your mind. This maybe a rotor from a 15" wheel vs the 16s on limiteds and sport models.
:cowboy:

http://www.toyota-4runner.org/3rd-gen-t4rs/94523-rotor-size.html

 

[nevada]

See post #8 (and others on same page) for a side by side pic comparison and related info, that'll make up your mind. This maybe a rotor from a 15" wheel vs the 16s on limiteds and sport models.
:cowboy:

http://www.toyota-4runner.org/3rd-gen-t4rs/94523-rotor-size.html

yes, physically they are overall bigger. but, that's not what matters, at least not in regards to the MC.

the bore size, the diameter of the piston is what will cause an issue. if its significantly larger, it will require more fluid volume. either by increasing the bore of the MC, or the length of the stroke. if you don't increase the bore, it will cause the pedal to be lower, and possibly soft. as you are now requiring more stroke to get the correct amount of fluid into the pistons.

has anyone pulled the pistons on each and compared them? or even mic'd them while in the calipers?
I just don't see how people are keeping the same pedal feel, while enlarging the piston bores.

 

[Mutant]

so the tundra calipers aren't bigger? then why do people use them? what is the advantage?

they are either bigger, or they aren't. but if they are, if the piston bore is bigger, you will need to adjust the MC bore accordingly, or you wont have the same feel at the pedal.

its physics.

My brake pedal was the same after the tundra upgrade. Drove for about a year with tundra brakes so far. But now after the MC swap it is spongy

Otherwise truck is fine since swap.

 

[HiluxSurf SSR-G]

I THINK, on the 199mm caliper, the pistons are the same while the 231mm calipers have larger pistons. that's why most of the soft brake pedal complaints after the TBU mod are from those using the 231mm calipers. However, most have been resolved after further bleeding.

...
has anyone pulled the pistons on each and compared them? or even mic'd them while in the calipers?
I just don't see how people are keeping the same pedal feel, while enlarging the piston bores.

 

[rebel4x468]

My 01 4runner has the ABS light, brake light and alarm going off - no brakes at the pedal and the ABS pump isn't coming on when you turn the key switch on. Other than buying a whole setup is there any other options that you or anyone else has found???

 

[nissanh]

^^^ See here: https://forum.ih8mud.com/threads/master-cylinder-rebuild-diy.406533/page-2

It is for the LandCruiser but very similar. I think somewhere there they speak about a shop in CA who fixes the booster pump. The worst thing that can happen to a newer toyota is this ABS brake pump failure!