WTB: Used 3.0CS Brake Calipers

bmwm3owner

bmwm3owner

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Hi Friends,

I am very new to this forum and I have just begun to work on my E9. I am in the process of rebuilding my brake calipers and I have one that has a piston that is severely stuck. I am interested in some used front and possibly rear calipers for my E9. My car has vented rotors all around and these calipers have the spacer between them to widen the box. I have seen some calipers out there that look like they are for solid rotor cars. I need calipers for Vented Rotors.

If you have some used calipers that are not frozen, I would be interested. Please DM me and lets chat.

Sash
 
I just rebuilt a set of the same calipers with some severely stuck pistons. I took them down to a local clutch and brake rebuilding shop and they blew them apart for me. The pistons and bores were immaculate once apart and the problem was the seals had rotted and had just major gotten stuck in the bores. They charged me a bit over $60 to do it. It took over 180#s of pressure to blow them apart.
 
Standard grease gun actually threads onto these calipers nicely. A bit of a mess but cleans up with brake cleaner. Will pop out almost any stuck piston.
 
bavbob said:
Standard grease gun actually threads onto these calipers nicely. A bit of a mess but cleans up with brake cleaner. Will pop out almost any stuck piston.
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I used Marvel Mystery oil to avoid the grease. It worked well on all the pistons, except for the one that is stuck. I cannot get that piston to even spin in the bore, no matter how hard I try.
 
Bert Poliakoff said:
I just rebuilt a set of the same calipers with some severely stuck pistons. I took them down to a local clutch and brake rebuilding shop and they blew them apart for me. The pistons and bores were immaculate once apart and the problem was the seals had rotted and had just major gotten stuck in the bores. They charged me a bit over $60 to do it. It took over 180#s of pressure to blow them apart.
Click to expand...
I called a machine shop and let them know what I was up against. He told me that it will probably be very difficult to get that piston out. I am currently soaking the caliper in Marvel Mystery oil. I was told that acetone and ATF work well with seized calipers. I may give that one last try before I completely give up.
 
Have you tried compressing the piston into the caliper with a c-clamp to break it loose? Sometimes a little back and forth does the trick.


Best, krauser
 
If you are gonna toss the caliper, I'll take it. Seriously, the grease gun will work and be a lot cheaper than a caliper.
 
Might be available from AdvanceAuto, they own Worldpac so usually only takes a day. Should be less than 50.00 ea (for the rears)
 
You need to be careful though. My front brakes were also seized. They came apart in the end but it turned out the piston had actually corroded and expanded making it very difficult to remove. It also turned out that expansion had damaged the casting anyway so had to get another set.
 
Thank you all so much for the replies! Awesome group. Rebuilt calipers from WorldPac, Rock Auto, etc. have not been in stock for a long time. I have been looking all over the place. No luck. New ones are way too damn expensive.

In terms of removing the pistons, I have tried using hydraulic pressure. I turned a grease gun into an oil gun and it works really well. Even the threading for the grease gun hose fits the calipers. All pistons came out, with the exception of one piston. Through some archaic means, I was able to fit some tools in the bore of the piston to create friction to try and spin the piston to break it free. No way in hell this thing is budging. I managed to break the lip off the piston, which holds the boot. I'm not as concerned about breaking that since I can get new pistons. I want to ensure I do not destroy the caliper bore. As Wes mentioned, his were badly seized. I bought this car from the original owner a few years back and decided to start working on it. The car has not been driven in 10 years. He stopped driving it because the calipers were seized and he decided not to put more money into the car. With the brakes sitting this way for years, no wonder there was a lot of moisture in the brake lines. I am hoping to get a decent used set to rebuild and have a couple of spares for later on. If anyone has any, let me know.

Thank you awesome people! I will have many more questions as I learn more about this car.

Sash
 
krauser said:
Have you tried compressing the piston into the caliper with a c-clamp to break it loose? Sometimes a little back and forth does the trick.


Best, krauser
Click to expand...
Its all the way in :(. I already split the caliper apart to soak it, so trying to put it back together and use hydraulic force is also probably not going to happen. If I could get the piston to spin a bit, then I may have luck pulling it out of the bore.
 
bmwm3owner said:
I called a machine shop and let them know what I was up against. He told me that it will probably be very difficult to get that piston out. I am currently soaking the caliper in Marvel Mystery oil. I was told that acetone and ATF work well with seized calipers. I may give that one last try before I completely give up.
Click to expand...

You might try soaking it in diesel fuel
 
Bert Poliakoff said:
You might try soaking it in diesel fuel
Click to expand...
I have seen people do that on YouTube. Seems to work well. I had several people tell me to use Acetone and ATF as well. I may try Acetone and Marvel Mystery Oil and see if I can get that last piston to budge.
 
All of us have tricks only becasue the parts are impossible to find. Impossible to find= mother of invention.
 
The local brake guy couldn't get mine apart either. He ended up taking them to a truck brake specialist as they had gear that could apply a higher load, which ended up working.
 
I was able to get my stuck piston out by leaving PB Blaster soaking around its edge, then putting the caliper back on the car, bleeding and then stomping on the brake pedal.
 
I have Volvo calipers on my 1600 and Chevy Citation calipers on my 58 Rambler. Both are vastly superior to stock with no additional drama. Surely someone has tried something on the E9...
 
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