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Brake Job Help Requested for 2012 LT 2.4L

2K views 7 replies 3 participants last post by  mraki 
#1 ·
Hello all,

It became time to do a front brake job on my son’s (used to be mine, original owner) 2012 Malibu LT (2.4L ~94k mi.) but I was going to check on the rear pads at the same time and do a brake fluid swap to complete the project. I found that the rears indeed needed changing but I was prepared with a stock of a new set. Unfortunately, things did not go according to plan.

The fronts were no problem – I’d done that job a few times before and it was a piece of cake. The problems started with the rears. I was able to rent the necessary brake piston installation tool but things didn’t go so well. It was extremely difficult to compress the driver’s side rear, almost impossible I’d say. That’s because the passenger’s side piston was, in fact, impossible. No matter how hard I tried to crank on the 22 mm thruster that applies pressure to the shaft that pushes on the piston, I couldn’t get it to move. A limitation was that I was using a Crescent wrench (a fairly large one but still) because I didn’t have a long handled, open-ended 22 mm wrench and even if I did, I’m sure I would have needed an extension of some sort to get additional leverage. If I didn’t know better, I’d say the piston is seized. Given the difficulty of pushing the piston in on the other side, it might be problematic as well.

For the time being, I put the old pads back in because the caliper won’t span the new pads. The car seems driveable with 3 sets of new pads but it’s certainly not ideal. I’m looking for recommendations here. Do I just get a long handle 22 mm open or box end wrench and crank on it? It is important to recognize that it’s pretty difficult to hold the caliper steady while you’re cranking down on the piston. If you’re answer the long wrench question is ‘yes’, then please suggest how to steady the caliper. Otherwise, what’s the alternative? Do I need new calipers, rebuilds or can these be repaired? I’ve seen repair kits for calipers but if the piston(s) is/are seized, does the caliper need to be bored out to remove the corrosion? There’s too many options to figure out the best path.

Any recommendations and suggestions are welcome and thanks in advance for your help.

-mraki
 
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#2 ·
Those pistons should be stiff turning but not to extent of major force cranking on them.
Looks like new / reman. calipers are needed as I've been down that road myself on various vehicles.
You'll get the fluid flush done when changing them also.
Piston adjusters binding will cause excessive pad drag so swap out those calipers.
 
#3 ·
Those pistons should be stiff turning but not to extent of major force cranking on them.
Looks like new / reman. calipers are needed as I've been down that road myself on various vehicles.
You'll get the fluid flush done when changing them also.
Piston adjusters binding will cause excessive pad drag so swap out those calipers.
Thanks for the reply, repairman54. As for the actual content, that's a bummer. But hang on just a minute. I just saw this link in this thread:



Have I been doing this incorrectly? I have been using the piston installation tool to apply pressure to the piston from inside the caliper outward. This is as opposed to the fronts where I used a C-clamp to apply pressure on the piston from outside of the caliper to push the piston into it. The article says that the piston has to be screwed back into the bore while the tool applies pressure to it. Do I have that right? If true, this would explain why I couldn't push the piston in on the one side but not how I managed it on the other. Maybe I got lucky?? Which way does the piston screw in, clockwise or counter-clockwise?

What I'm not quite grasping is how one rotates the shaft of the thruster (which would rotate/screw the piston) at the same time as rotating the 22 mm wrench that applies pressure onto the piston. Is alternating back and forth, a little more pressure, a little more rotating the right technique?

I'm not sure why a straight travel piston was good enough for the fronts where most of the braking load is, why it wasn't good enough for the back. Well, that's not my issue I guess. I just have to fix it. Thanks in advance to any who participate.

-mraki
 
#4 · (Edited)
The parking brake uses the screw threads on the rear brakes to do its work. If there was a parking brake on the front, they'd have screw-in pistons as well.

Something else I overlooked sharing: I did the pads and rotors on all 4 wheels several years ago and had no issues with the rear pistons. I wonder if it has anything to do with the fact that I rarely use my parking brake?
 
#5 ·
When you said ...


does the parking brake and pedal actuated brake use the same piston to apply the pad to the rotor? In other words, a screw action is needed to cause the retraction, right? I need to know whether to try again with the piston installation tool or whether I need remanufactured calipers. I guess no loss is trying to former first but one never know when one is up against futility, right? One can go a long time based on faith before one gives up.

Neither I nor my son used the parking brake much but I used it to hold the wheel to loosen the bolts so I know it applied and released fine (holding and releasing the wheel properly). So, if it uses the same piston, it's definitely not seized.

-mraki
 
#6 ·
When doing a brake job one screws the pistons back into caliper as well as pushes back in the piston assy. .
Parking brake self adjusts pads by screwing out the inner piston to compensate for pad wear. Brake pedal applied pushes out entire piston.
All done by the one piston.
I've had pistons go in/out OK but be frozen when trying to screw back in.
Sometimes with everything retracted properly the caliper/pad assy. can be a tight fit going on over the rotor.
 
#7 ·
OK, I'm not exactly sure of the exact tool technique but that's OK. I think I've got an idea about a few things to try about how to apply the tool so that "one screws the piston back into the caliper as well as push [it] back in the piston assy". I'll get back to try it this weekend and I'll report back after the attempt.

Thanks repairman54 and DrivenDaily. I appreciate the assistance.

-mraki
 
#8 ·
Success! So the best news is that the caliper(s) are not seized and using the brake piston tool worked great once I tried a different technique with it. If anything, it was a switch almost completely to a rotation/screwing technique rather than the compression one I had been using. It was such a complete switchover and became so easy that I thought I may have done the other side incorrectly or even broken the other caliper since it was done almost completely with compression.

I went back to check on the other side and it seemed okay. With all four new sets of pads, I went about changing out the brake fluid and all went smoothly. The final test drive increased my confidence that the job is done correctly. Thanks all.

-mraki
 
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