Orpheus

Hi,

So, I toasted my brakes at the track and was able to make it home. Replaced with rebuilt calipers (all corners), a new master cylinder (found a small leakage into the booster), and all new rotors. And the brakes still seem "mushy." I can pretty easily push the brakes all the way until they hit the stopper.

The brakes have been bled many times via RBF600, 2x by a pro shop at the track (didn't fix the problem), and 3x via pressure at another shop after changing my parts, one of which after I drove out and heat cycled everything, including activating ABS many times.

There are no leaks. Between the incident and now, fluid level always remained the same in the MC, and there are no traces of fluid around lines or joint or anything.

Any ideas? Two I can think of:

1. ABS system? Could this possibly affect anything? I figure even if the ABS system is broken, it's a closed system, so couldn't affect pressure could it? Possibly air STILL stuck in ABS?

2. Brake booster? I dunno... I thought a broken brake booster would just make the pedal stiffer right? No hydraulics in the system right?--so there's no way for a bad brake booster to move the plunger in the MC even less with same travel in pedal right?

Oh, and I should note again, the brakes have enough power to activate ABS as it is now. Using Carbotech XP10/8 pads, which grab harder than stock. So, not sure if there is enough power to stop with standard brake pads.

Have a track day on Sat, so hoping I can get this sorted out. Thanks for your help.

GrandMasterKhan

we had a similar issue on an accord recently. ABS module could be bad and causing your problem.

Orpheus

that would be very bad news as the abs module is $750:

http://www.hondaautomotiveparts.com/auto/j...ATOR+%28-+03%29

guess i could get a used one.

i should note that abs itself works perfectly fine... i push on the pedals, and abs activates when the tires slip, and front/rear balance feels fine to me (not that i really tried testing the balance.)

if it's the abs, would a honda tech be able to diagnose it?

SpitfireS

Rear calipers.
The e-brake system is hard to bleed when you start with an rebuild / empty caliper.
I ended up bleeding it, while holding it in my hands, bleeder perfectly upwards, tapping it with a small hammer.
Some small bubbles showed up in the bleeder hose!

All during a gravity bleed.

chuhsi

i'm going to also guess brake fluid even though it's been bled so many times.

GrandMasterKhan

you should try hitting abs many more times and rebleed the system yet again. be slow and patient. it is after all very possible you have air in your lines still.

My suggustion of an ABS module is not conclusive at all. A Honda tech would very likely be able to Diagnosis it i am sure. But like many have said i'd try bleeding even more before you go that route.

Orpheus

yeah, thanks for the tips guys. i think i'm gonna try spitfire's technique tomorrow. can't really think of anything else.... must either be air in lines or the abs system (though the abs does work perfectly fine).

strange thing i noticed today was that with the ebrake pulled really hard, the brakes actually do firm up. i'm not sure if that really means anything though... but maybe that has something to do with spitfire's idea. anyway, crossing my fingers.

dsthez

did you check the caliper slides if one is frozen it will have that effect.

SpitfireS

Orpheus Posted on Nov 5 2010, 07:58 AM
The e-brake system mechanically moves the pads.
So its not strange, its safe

twohoos

Long shot, but make sure you're bleeding in the right order? LF-RF-RR-LR.