E30 Brake Caliper Rebuild

How-To Credit

This how-to was written and provided by user “knotcher” on the R3VLimited forums, with minor edits for this site. Thanks for the great write-up!

Parts

Brake caliper rebuild kit:
- Front – for ATE brakes (34111157043)
- Front – for Girling brakes (34111154440)
- Rear (34211153194)

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Tools

O-ring remover or small screw driver
Brake cleaner
Brake fluid

Prodedure

Start with a clean work surface
Clean your bench and lay out your rebuild kit(s)
On the rear calipers, remove the dust cover retaining ring
Pull the ring and boot off
If you have compressed air, shoot a little into the brake line hole. be careful as the piston will come out pretty quickly, so stick a rag or a block of wood in between the piston and the caliper so that it doesn’t do any damage. if you don’t have compressed air, you can use a bike pump with the cone nozzle.
After you get the piston out, pull out the inner seal. Be careful not to scratch the wall of the caliper bore.
Clean out all the nasty stuff with brake cleaner and a toothbrush (nothing metal, so you don’t scratch the walls).
Now it’s time to put it all back together. Soak your inner seals in clean brake fluid.
Fit the new inner seal in its slot.
Gently stretch the dust cover over the piston.
Spread some brake fluid on the piston and bore walls and carefully push the piston back in. You should be able to do it with just your hands. If you get stuck, take it out and try again…don’t get frustrated if it takes you a couple of tries.
Put the retaining ring back on and you’re all set.
The fronts are a little harder than the rears…pull the boot over the piston like this:
Tuck the boot into the slot in the caliper like this…it’s hard…take your time and it helps to lube it all up with brake fluid.
Push the piston in until the front of the boot slides into its own slot.
Re-Assemble the rest of the calipers and reinstall on the car.
Bleed the brakes.