Doing front brakes right now.

I remember reading some thread where the guy compressed the caliper without opening the bleed valve, and it seemed like he might have destroyed his ABS modulator.

But just now reading the RAVE, it just says to compress the caliper with no suggestion to open the bleed valve.

I'd rather not open the valve to avoid the risk of air in the system, but obviously I don't want to damage the modulator.

What should I do here?

 

can not see how it would hurt to crack it open, but I never have. i just bleed afterwords. hope I'm not screwing up that bazillion dollar modulator

 

Stick a hose on the bleed screw, stick the other end in a jar, open the bleed screw and compress the caliper.

 

I went ahead and cracked them. I tried to crack them just a bit and prevent air from getting in, but it didn't work and now I have air in the system. I hate bleeding brakes an incredibly huge amount. I bled the front two but the pedal's still mushy so tomorrow I pull the rear wheels and bleed 'em all.

Also, right pad is ground to nothing, left pad is almost new.

Hmm...

Thanks for the help.

 

Please come back to the forum in a few days to report
- If the 3 amigos showed up,
- If you remember turning by hand the rotors by any reason during the pads replacement,
- If you did the servicing with battery connected or disconnected.
- If the pedal improved after the initial wearing of pads, or after and additional air purging.

Check right side rotor temperature after running a while with as little as possible brakes application. Is it touchable or will burn your hand ?
Thanks.

 

You're going to have a soft pedal because the brake fluid circuits are diagonal. LF and RR on one circuit. RF and LR on the other. Bleeding just the fronts or just the tears does no good because you are only getting the air out of half of either circuit.

 

Also, regarding the uneven wear, make sure the slides on the RF caliper are clean and we'll lubed. Could be lack of lube, or maybe just air in that circuit. Since you were able to compress the piston back in when you bled the RF chances are the piston is ok.

 

- No amigos after short test drive with lots of hard braking that engaged the TC and ABS
- I definitely turned the rotors by hand quite a bit
- Battery was connected
- Initially the pedal was very soft, after bleeding the fronts it got much better, but still too soft
- I checked the temp 10-15 minutes after the test run and the right side was 130, the left was 112.

909Wheeler -

I have mixed feelings about the caliper. The brakes worked fine before, with no pull or other indication of a stuck caliper and a firm pedal. I never smelled hot brakes. But the last drive I was on I did smell hot brakes and realized the right front brake was smoking when I stopped to investigate. The pad was completely worn thru. After the new pads, they still don't pull and act totally normal besides the soft pedal. The temp of the right disc does read higher than the left, so it is grabbing a bit more on that side even if I can't feel it in the steering wheel.

I'm leaning towards new front calipers, but I certainly don't want to waste money. I did work the slides while I had it apart and they seemed ok, though I wasn't inspecting them so much as messing with them.

I DO appreciate the help in diagnosing the problem!

 

As a matter of info, I recently replaced my discs and pads all round. When it came to retracting the caliper pistons I used a 'G' clamp Résultats Google Recherche d'images correspondant à http://upload.wikimedia.org/wikipedia/commons/2/2a/G-clamp.jpg and gently retracted the pistons ensuring the brake fluid reservoir didn't overflow. My tip is don't retract the pistons too rapidly and don't try to force them faster than they want to go - gently does it. The brakes and pads have bedded in after 100 miles and work fine again now. It saves any brake bleeding etc.

 

I think you're right - the key is to do it slow.

I bet people who messed up their ABS modulators just squished 'em down.