Brembo Brake Mod Problem

[1tracmind]

Hey...I'm trying to help a friend w/ a mod. He just bought a 2001 TLR that has a front Brembo brake mod. During the first mile or so of his test run on the bike, the front calipers started to clamp down on the rotors…w/out any brake lever manipulation. Shortly thereafter, the calipers clamped shut on the rotors. He couldn’t budge the brake lever...no matter how hard he pulled.

I've done several mods, but I've never heard or seen this happen. What am I missing? What is causing the calipers to activate on their own, and how do we fix it?

[smokescreen]

prolly it's time to bleed the brakes. they will unclamp, once you've drained the brake fliud. But don't expext them to work again untill you've refilled and bled them.

I soppose this could happen if the brakes calipers are in need of a rebiold to. They may have siezed. But try draining, refilling and bleeding first.

If they require a rebuild, well, those are easy enough, but he'll learn why People like Tokicos so much. Seal kits for Brembos, aren't for the budget concious.

[zippytls]

I believe your freinds brake fluid looked.. well um... like maple syrup?? Yes?? anyhow... your freinds fluid had absorbed too much water-meaning it had not been changed regularly. It should be done at least once a year. Or if it looks like brown sugar, which ever comes first. So, with the fluid having absorbed the water... when the rotor spinning betweeen the pads... lightly dragging... they heated up. The heat inturn boiled the moisture in the brake fluid,causing it to expand and further clamp the pads to the rotor untill they finally "locked". Just let it all cool down. Then flush the system with fresh fluid, bleed the air out... and your freinds brakes should be ok. If the fluid was goooey looking and left that way for some time... the brake calipers may need to be throughly disassembled and cleaned and put back together. The water in the brake fluid will allow corrosion to begin... keeping the pads from retracting that onemillionth of an inch when the brake lever is released. Clean out all that corrosion, replace the seals and dust boots if they need it and you should be good to go!

[1tracmind]

Thanks...I haven't seen the bike yet, so I don't know what the fluid looks like. But...to keep things simple, I'll check the basics first. If his brake fluid is old or like syrup, we'll drain it, refill and bleed the brakes. I know he doesn't want to deal w/ the expense of a brembo rebuild. Maybe it is something simple.

Thanks...I'll let you know how it goes.

[blong]

Does he have the correct lever on the master? If the lever doesn't let the piston in the master retract all the way, it will build up pressure every time you hit the brakes and lock the wheel.

[crashrat]

Yes. Been there, Done that. GSXR front end, Brembo MC (Ducati 916/748 application, 16mm 10.5053 )

I had the front end lock up several times during test rides -
:( not fun at 70mph in the left lane when your front brake starts to lock up. I had about 1.5sec of warning that something was seriously wrong (the front end started to load) and basically dove for the exit lane - by the time I stopped the front tire was skidding, the rotor was searingly hot and the lever at full lock. About 10 minutes later, it was ridable again.

.. checked everything and took it out for a test ride -- lockup happened within about 2 miles. Lever full out, almost no play, locked pistons. Cooled down and was able to run it about 3/4 minutes later. Several test runs, moderate braking (and a few small stoppies) couple of miles, nothing. Bike back at the garage, rotors cool, no dragging, looked normal.

did a partial teardown and checked alignment/friction/dragging, runout (+/- 3 thou) etc.. rotation was about 1.80 turns. Talked to one of the guys down at Brembo NA (Robert Zaragoza) and he verified the MC bore and fit (it's a 10.5053.13) and confirmed it was a decent match up with the Tokico 4 pot calipers. One of the local guys (ernie/afm199) pretty much nailed it, and the voice of experience said check for dragging brakepads and clogged bleed-hole in the MC. Went though it again..

The basic problem as far as we could determine was a combination of a sticking piston in the 4 pot Tokico leading to an overheating brake, and a blocked bleed hole in the Brembo remote reservoir. Thanks Ernie! It's been fine ever since. :D The bleed-hole is tiny and if I didn't know it was there, I'd have never have guessed. Such a miniscule thing can create such lethal havoc, scary. :cool: