Rear Brake Pistons

[Propflux01]

I have a question on rear brake caliper pistons. I just did all 4 brakes on my Elantra, with new rotors, pads, lubed the sliders, etc. On the rears, the piston has one of those type that needs a tool to turn it in a clockwise direction to retract the piston. I did this, with the tool, everything went great. I did the rears first, and when they were done, I pumped the brakes back up until they got firm. Then went on to the fronts. After completion, I took the ca out for the 60 to 30 braking bedding-in, and came back. The fronts looked great, nice grey finish appearing on the rotors. The rears, don't even look like they were ever working at all. Now, since those pistons have to be turned to retract, to they expand to take up clearance in the same way? Shouldn't there have been some kind of wear marks on the rotor? They held the wheel just fine when brakes applied and trying to turn the wheel while up on jacks, so I know they are clamping and unclamping as advertised. Whats the story with this?

 

[atikovi]

Front brakes do most of the work. Unless the pedal feels soft, you're fine,

 

[92saturnsl2]

The rear rotors after a drive should be warm. If they are completely cold the piston may be stuck, which is not terribly unusual for those rotating pistons, but then again that car is pretty new. You probably won't see any noticeable amount of rotor wear after a short drive, but the brakes should at least be heating some. That said, they won't heat nearly as fast as the fronts but they should not be cold.

 

[Propflux01]

Ill give it a few more drives and see what its doing.

 

[mclasser]

Whenever I've done rear brakes on my cars, it seems to take a while for the even finish to develop. You're saying they're clamping and unclamping when jacked up, so I'd just give it more time.

 

[JHZR2]

Originally Posted by atikovi
Front brakes do most of the work. Unless the pedal feels soft, you're fine,


+1

 

[supton]

Maybe braking too hard. Brake less hard? Depends on if your car has electronic brake distribution, where they engage the rears first, to try to control brake front end dive during braking.

Usually when calipers go for me, they drag. I did have set where the pads got stuck and didn't do much, but that I consider a fluke.