Sticking rear disk brake

[M.H.Farshid]

Dear all,
hi, since a couple of days ago i’ve got a sticking rear brake problem on my fiat Stilo from 2005. first i noticed the sticking rear brake pads moving the car after standing still for 2 weeks with hands brake on.
i thought it would be a temporary issue, but i see that the problem remain. you can feel the brake disk is much warmer than all other three wheels brake disks.

after alot of google search and couple of ETCG videos, i tried first to disassemble the calliper and clean/lubricate the sliding pins with silicon paste (not grease of course) which didn’t help. then i bought a whole calliper assembly from salvage yard, and replaced the the whole thing, winded the piston back (which was hard to wind with the proper tool), bleed the brake, but still no improvement. i thought the brake hose may be an issue, but i see with bleeding that plenty of fluid comes through…
somehow, from the first time brake after install, the piston fail to retract and the whole thing get stuck!
i really dont know what reason can be. of course there is a chance the second calliper may also be dead but the seller says that they test the parts and they works and they give three months guaranty… i can buy a new calliper but i wonder if that would solve the problem, and of course i try to avoid unnecessary costs. i checked the ECU for error, there are no faulty errors on engine ecu or ABS system either.

so, here is my question ETCG Experts, what the hell is wrong with my car or what am i doing wrong? what blocks the oil in the brake to go back and the piston fail to retract after releasing the brake (hand and foot-brake). could it be a failure in abs system (drain valve) and is there any way to check that out since there are no error records?
anyway, any help will be appreciated, and of course i thank you for your time and all the videos you made available.

best regards
Far, Netherlands-europe

Topic

[college man]

If when you bled the brakes and good fluid came out of the
caliper bleed screw then the hydraulic pressure is there. I
would have to say bad caliper. Before you got the caliper
someone could have tried to reset the caliper by pushing it
in which will ruin it. The reset tool must be used. which you
did. I would get a new one or reman. This way hopefully you will
be good to go.

[Kenneth]

I’m not familiar with the brakes on this type of car. So all I can offer is a generic suggestion.
Is there an e-brake cable, that might be sticking? Possibly adjusted too tightly? Could it be removed, long enough to see if this affects the issue?
A new hose can never hurt, and sometimes can solve the problem. Since hose problems typically happen internally, the damage isn’t always visible. A new hose, isn’t very expensive, and would eliminate a potential cause of the problem you’re having.
If it were my car, I’d eliminate all the other potential problems, before I bought a new caliper. This way I’d feel that I’d sufficiently isolated the problem. And know that I hadn’t overlooked a cheap, easy fix.

[M.H.Farshid]

thank you guys for your input. handbrake mechanism is fine, i dont see anything that can make any problem, i even unhook the cable to see if it has any effect…
today i took my old calliper apart and put new o ring and dust boot on. the piston was very difficult to to remove, once disassembled i saw some rust on the piston. after cleaning,smoothing, maybe excessive silicon-ing, put it back together and i should say it went pretty easy back in, with not much force, tomorrow im going to mount it again back on the car… i should say im curious if it works as it should…
i still dont get it how the piston suppose to retract after releasing brake pedal. is it done by master cylinder (by creating vacuum to suck the oil back or by the small coil spring back in the calliper…
after replacing the calliper again i’ll let you guys know what happen. thanks you both gentlemen for your tips.
Me,

[M.H.Farshid]

faulty calliper indeed, the rebuild one did it as good as new… 🙂

[college man]

[quote=”Far” post=118145]faulty calliper indeed, the rebuild one did it as good as new… :)[/quote]

Glad to hear you got it. 😉

[Kenneth]

[quote=”Far” post=118145]faulty calliper indeed, the rebuild one did it as good as new… :)[/quote]

Well done sir!

[Author]

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