DIY - Brake Caliper Rebuild

[knotcher]

I'm in the process of building an e30 race car. i haven't put up any good tech yet so i thought i'd give it a shot. feel free to read about the build if you'd like.

1. start with a clean work surface


2. clean your bench and lay out your rebuild kit(s)


3. on the rear calipers, remove the retaining ring


3. pull the ring and boot off


4. if you have compressed air, shoot a little into the brake line hole. be careful as the piston will come out pretty quick 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 nozzel.


5. after you get the piston out, pull out the inner seal careful not to scratch the wall of the caliper bore.


6. clean out all the nasty stuff with brake clean and a toothbrush (nothing metal, so you don't scratch the walls).


7. so now it's time to put it all back together. soak your inner seals in clean brake fluid.


8. fit the new inner seal in it's slot and then stretch the boot over the piston as here.


9. 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.


10. put the retaining ring back on and you're all set.


10. the fronts are a little harder than the rears...pull the boot over the piston like this


11. 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.


12. push the piston in until the front of the boot slides into it's own slot.

[nando]

nice, I'm about to do this soon. I just discovered my front right caliper is sticking - pretty much gone through 2/3rds of my new hawk HPS in less than 6 months. :(

[evil_twin]

Nice write up. You are taking all the jobs away from technicians like me :) lol.

[Schniddy]

04 VENTILATION VALVE 2 34111121206 $6.25
05 DUST CAP 2 34111153198 $2.79
10 REPAIR KIT GUIDE BUSH 2 34111161936 $21.54
09 REPAIR SET BRAKE CALIPER 2 34111154440 $24.83
03 HEX BOLT M12X1,5X32 4 34111118948 $1.67

Front Pistons P/N?

08 GUIDING BOLT 4 34111157041 $20.98 = 83.92
05 VENTILATION VALVE 2 34111153197 $6.14
06 DUST CAP 2 34111153198 $2.79
4 HEX BOLT M10X30 4 34211153937 $1.12
20 REPAIR SET BRAKE CALIPER 2 34211153194
21 REPAIR KIT GUIDE BUSH 2 34111157038 $15.23

Rear Pistons P/N?


This list seems to be more expensive than paying $45 for an already rebuild one fap or bma. What's the deal?

[knotcher]

i don't know that you need all that...all i spent $12 (front) and $10 (rear) for rebuild kits (boots and seals) and another couple bucks for caliper guides. it was worth it for me.

[Beej '86 325es]

04 VENTILATION VALVE 2 34111121206 $6.25
05 DUST CAP 2 34111153198 $2.79
10 REPAIR KIT GUIDE BUSH 2 34111161936 $21.54
09 REPAIR SET BRAKE CALIPER 2 34111154440 $24.83
03 HEX BOLT M12X1,5X32 4 34111118948 $1.67

Front Pistons P/N?

08 GUIDING BOLT 4 34111157041 $20.98 = 83.92
05 VENTILATION VALVE 2 34111153197 $6.14
06 DUST CAP 2 34111153198 $2.79
4 HEX BOLT M10X30 4 34211153937 $1.12
20 REPAIR SET BRAKE CALIPER 2 34211153194
21 REPAIR KIT GUIDE BUSH 2 34111157038 $15.23

Rear Pistons P/N?


This list seems to be more expensive than paying $45 for an already rebuild one fap or bma. What's the deal?

I don't think BMW ever sold just the piston. But Bimmerworld sells some they've manufactured.

$45 for a rebuilt caliper? I assume they're sold on an exchange basis?

[Schniddy]

^Yup, there is a core charge.

So buying new rebuilt ones are cheaper than rebuilding a set yourself..weird

[thereisnoyun]

^Yup, there is a core charge.

So buying new rebuilt ones are cheaper than rebuilding a set yourself..weird

you just need seals, and maybe the guide pins. but... having said that, I would just buy a rebuilt one.

But I think the biggest problem with most people is that they dont have another set to ship in and have to wait for another one to come in. And doing all four repair at the same time, its definitely worth it if it means you can drive the car the next day.

[Mless5]

With front calipers, I actually use different method, but you will need 4 hands for that: you stick the boot in the caliper first, than while you open up the boot a little, have your helper insert/spin the piston in the boot.

[Money$hit]

With front calipers, I actually use different method, but you will need 4 hands for that: you stick the boot in the caliper first, than while you open up the boot a little, have your helper insert/spin the piston in the boot.

Ill have to try that. Just rebuilding them like in this thread is a bitch. I just did mine, and I think they need re-bled.