compressed piston too far..help!

[m.dystynkt.m]

changing the pads (front) on my 95 ///M3 i accidentally compressed the pistons before putting the pass. side pads on so now i am trying to well uh push the piston back in using a C clamp but even using 2 people we are barely getting it to budge..any ideas?

[GEN3RIC]

lots of peanut butter



... Kidding. In for curiositys sake.

[m3ltw98]

What I did when I had to move the piston a bit was:

-remove cap from master cylinder.
-put piece of cellophane over hole w/ rubberband
-crack open the bleed screw a tiny bit and push the piston in w/ the c-clamp or your hand.
-tighten bleed screw and your set

Goodluck

[m.dystynkt.m]

any other ideas? ^^sounds hard (not to mention kinda confusing) since i dont know much about brake work

[m3ltw98]

any other ideas? ^^sounds hard (not to mention kinda confusing) since i dont know much about brake work

If you cant understand what I wrote, you shouldnt be working on your car. Just open the bleed screw on the caliper a bit to releave pressure and push the piston in by hand. Just make sure to tighten the bleed screw before going for a drive

[m.dystynkt.m]

well that makes more sense now..i didnt understand the whole cellophane part. this is pretty much the first time ive worked on brakes and everything is a learning experience..i'm sure you would not have learned either without some help. thanks tho i really appreciate it!!! :)

[m.dystynkt.m]

i read some other posts on bleeding the lines and they said to tap the brake pedal. i got (i believe) a lot of the fluid out there is barely any more coming out but i still cant get the piston to go back in. ahhh im dyin here!

[m3ltw98]

If you leak a little more than a few drops, you ok. You'll know your compressing the piston further because fluid will squirt out of the bleed screw hole. Open it a little further and try with your hands or a big pair of pliers wrapped in a shop towel so you dont damage the piston.

[m.dystynkt.m]

i think all the fluid is about out and it wont (the piston) push in any more. im pretty sure i did everything you said right as i went over it a bunch of times i just dont know why its not working for me.

[m3ltw98]

Have you tried putting the inner brake pad in the piston and the other on the pad bracket and squeeze the caliper over the pads? I know sometimes you gotta wiggle the caliper a bit to squeeze the caliper and pads over the rotor. Give that a try before you lose all your fluid.

[m.dystynkt.m]

the piston was compressed so much that i was barely able to fit the inner brake pad on to put the c-clamp on. i think i finally have it pushed in enough where i might be able to fit both pads into the caliper but not near enough to get them even close to going onto the rotor.

[m3ltw98]

Snap a picture or 2. I gotta see how far out the piston is. If you can, either post them here or email me them at jsedacca@gmail.com Thanks

[live2roll]

heres the pic
btw its for my car i was on my bros comp earlier and on his name

[m3ltw98]

heres the pic
btw its for my car i was on my bros comp earlier and on his name


Ouch, the reason the piston will not go in is because the rubber dust boot was unseated from the annular grove in the piston bore. You need to pull the piston out and reseat the rubber dust boot. Follow these directions and you'll be fine: http://www.unofficialbmw.com/e36/brakes/e36_lets_brake_it.html

A tip I learned is to soak the rubber dust boot in new brake fluid and soak the piston as well. It will make things a lot easier to work with and will help the piston slide in. If you need anymore help, let me know. If I were closer, I'd certainly help you out. Let me know. Thanks

[M3motorsport]

Dude, I think your piston popped out of an inner seal, plus from what I see on the picture seems like it is not aligned strait that is why you cannot push it back.
Make sure piston is aligned correctly (remove outer rubber boot if it helps, you will put it back once you done), try to push piston back in you may have to use a bit of force (use an inner brake pad if it helps).
Again piston must be aligned strait or you can bait off piece of an inner seal (if this happens your caliper will leak) and you will have to buy new seal from dealer.
Oh yes don’t forget to bleed the system once you done, there is probably air in the line at this point.
Good luck

[m3ltw98]

Dude, I think your piston popped out of an inner seal, plus from what I see on the picture seems like it is not aligned strait that is why you cannot push it back.
Make sure piston is aligned correctly (remove outer rubber boot if it helps, you will put it back once you done), try to push piston back in you may have to use a bit of force (use an inner brake pad if it helps).
Again piston must be aligned strait or you can bait off piece of an inner seal (if this happens your caliper will leak) and you will have to buy new seal from dealer.
Oh yes don’t forget to bleed the system once you done, there is probably air in the line at this point.
Good luck

He needs to remove the piston to reseat the dust boot correctly and to make sure the piston is straight. When you remove the piston, make sure the inner fluid seal is still in the piston bore groove. This will prevent leaking like mentioned above. Your better off taking the caliper off and working on it in a vice. Follow the directions I linked above and you should be fine. If you need help, feel free to PM or email me. Thanks

[live2roll]

yikes guess i really messed up! after i follow those directions and get that all done will i have to bleed the whole system? When i was trying to bleed it today i think i about ran out of fluid because it leaked to the point where it didnt leak any more :(

[m3ltw98]

Bleeding the entire system is a good idea. Since you took the caliper off, a lot of air is in the lines. Shouldnt take much of a bleeding to release them since the caliper is gigantic. Goodluck