Removing front brake caliper piston

[///M3-=FiN=-]

I have a slight problem.......I was removing my calipers because I am gonna paint them only to find out that the rubber ring on the piston was cracked......now I need to replace the ring but need to remove the piston as well......has anybody done this before? If so do you need to rent or buy a special tool to get it off? Is it possible to get the rubber ring on without removing the piston?

thanx

[jsp98m3]

You must remove the piston. There is one way to do it.

1. Remove the brake line.
2. Put rags or a scrap of wood into the caliper where the rotor would normally be. This is to proect the piston.
3. Use an air nozzle on a good-sized compressor to blow air into the brake line fitting of the caliper. The air will push the piston out.

The rags or wood keep the piston from launching. It will and it hurts. Keep your fingers out of the way.

Also blowing air into something that had brake fluid in it is dangerous to your eyes and everything else within umpteen feet. Wear goggles and drape a towel over the whole thing to catch splattering fluid.

Have fun with the rebuild kit. It's a bitch-kitty till you get the hang of it.

[jayhudson]

Good one, Jim!!

[///M3-=FiN=-]

Thanx for the advice.......I will prolly get started early in the morning.

[///M3-=FiN=-]

Oh yeah, is there any websites with instructions/ how to?

[jsp98m3]

Before you start, study the instructions carefully. Oh, and learn German first

The secret to the dust boot is to follow their cryptic instructins which basically say to put it on inside out on the end going into the caliper first. Then seek God....

A very worn blunted straight screwdriver can help get the thing seated all the way around. Use a new one with sharp edges and you better have the hands of a heart surgeon.

The first one can take forever. The second 5 minutes, the third 30 seconds, the fourth is 5 seconds.

Now that I learned that secret, I just put the last one on first to speed things up. <== That's a joke. Take your time, keep everyting lubed with brake fluid so it doesn't get dry and rip. And by all means, completely bleed the brakes on reassembly. And before leaving the garage, pump the pressure back up and top off the master cylinder. Otherwise, you crash and go boom!

[UD///M]

Originally posted by jsp98m3

The rags or wood keep the piston from launching. It will and it hurts. Keep your fingers out of the way.

Jim, I am not going to enquire about how you know this. But I guess you still have 8 fingers and two thumbs.

[jsp98m3]

Ummmmm.......

[UD///M]

:

That is a good pic. But I know I saw more fingers than that in some of your other pics on your website. Or was that a body double.

[jsp98m3]

I take pics using assistants sometimes. Sometimes I'm the assistant also. Its ard to do some things one handed and aim the camera too. Besides being dangerous.

7.5 fingers is all I can muster. Rock slides are dangerous.

[Stockman]

its also dangerous to type 1 handed.. could put out an eye or something..