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.

i have them on my 01 without issues.

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.

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.


Rotor size

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.

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.

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.

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???

^^^ See here: https://forum.ih8mud.com/threads/mas....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!

How many miles do you have?

Most of these Master Assemblies seem to fail around 230k miles.

You might get lucky doing a rebuild of your unit. However, you may not. There's not that much info out there for fixing these when they fail. In fact, Toyota recommends you do not even attempt it. Some guys have had luck tearing theirs apart and replacing cheap little parts like O-rings and springs. It all depends on how much time you can spend on it and how handy you are. I doubt you will find anyone who would rebuild it for you.

The most cost effective and easiest route is to buy a used assembly with 100k miles from eBay for about $490. Install yourself or get an import mechanic to swap the units for $200 or $300. Can get running again for around $750. And it should be good for at least 130k miles.

I've heard of people swapping out their 01-02 MC with an older one.

Just happened to see this ad and was reading this topic this morning and though if anyone is in this area...South Carolina....you might want to jump on this.

https://charleston.craigslist.org/pt...352241884.html

DAYUM, G

It's threads like this that make me glad I own a 99, and I will only ever buy a 99 or 00 4runner, unless just for parts.

Don't be scared of technology and the future. You will miss out on a lot. Haha.