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View Full Version : Sticky front driver's side brake caliper


anandoc
11-12-2015, 04:54 PM
This is related to the WTB: Front driver's side brake caliper thread I posted earlier today. [here (http://www.zhpmafia.com/forums/showthread.php?17006-WTB-Front-Brake-Calipers-330i)]

I discovered a sticky front driver's side caliper a few days ago. Ayan (orange260z) and I took apart the offending caliper and cleaned and lightly lubed the guide pins and put everything back together.

However, it seems that once I hit the brakes and then release it, the caliper still clings on to the rotor (like a crazy, clingy ex-GF) and does not back off. If I use a flat-head screw driver and pry the caliper back, the hub is able to rotate freely again. Hit the brakes again, same thing all over again.

Any clues why the caliper piston wont retract? Is the piston shot and I just need to get new calipers? Any tips would be appreciated!

PS: Just got home after all this troubleshooting drama and I realized that I left the wheel lock on the lug nut after torquing down the wheel and now its gone :(
Vas
11-12-2015, 07:35 PM
I would pull back the dust cover on the piston and look at it. Most likely the piston has rust on it.

This is what you call a frozen caliper.
Scott ZHP
11-16-2015, 06:36 AM
Bad seal/rusted piston or both.
ryankokesh
11-16-2015, 08:33 AM
Yup, time for a new caliper (or rebuild).

Just gonna go ahead and leave this here... BBK (http://www.tirerack.com/brakes/brakes.jsp?make=Brembo&model=GT+345mm+Big+Brake+Kit&group=GT+345mm+Big+Brake+Kit&autoMake=BMW&autoModel=330i+Sedan&autoYear=2004&autoModClar=Performance+Package&cat=BigBrakeKits)
anandoc
11-16-2015, 01:46 PM
Just gonna go ahead and leave this here... BBK (http://www.tirerack.com/brakes/brakes.jsp?make=Brembo&model=GT+345mm+Big+Brake+Kit&group=GT+345mm+Big+Brake+Kit&autoMake=BMW&autoModel=330i+Sedan&autoYear=2004&autoModClar=Performance+Package&cat=BigBrakeKits)

Haha I hate you ;) I really wanted the ECS Tuning BMW Performance BBK but I just cannot justify the price tag for some extra bling.
anandoc
11-23-2015, 04:06 PM
Got the calipers replaced and the issue is gone. Clearly, it was the caliper piston sticking - probably due to rust build up inside. Thanks again to all of you for providing all the guidance on this issue.
slater
11-23-2015, 05:34 PM
awesome! :cheers
BMWCurves
11-23-2015, 05:45 PM
Congrats! Glad to see the family come through for you.