Piston won't compress on rear brake caliper

Robotaz · Post by **Robotaz** » June 18th, 2005, 7:07 pm

Anyone familiar with a problem just compressing the piston on the rear calipers? I opened the bleeder valve and only get fluid out from the line, not the piston compressing.

Robotaz · Post by **Robotaz** » June 19th, 2005, 10:15 am

I just read that rear hummer pistons have to be turned while they are pushed in. Could this be my problem? Obviously getting the tool from Mazda is out of the question.

Shades · Post by **Shades** » June 19th, 2005, 12:31 pm

Looks like you have a case of the siezed piston. This is common over time and use. You can either replace the whole caliper unit or try and rebuild the caliper yourself. You will get fluid out the bleeder valve, but this doesn't affect the piston being stuck.

Good luck.

Robotaz · Post by **Robotaz** » June 19th, 2005, 1:09 pm

Stupid me! I forgot Mazda has a gay-a-- trick to do anything on their cars. The damn thing screws back in. It has notches cut out to grab on and turn the piston by the face. Thnx anyway.

mitmaks · Post by **mitmaks** » August 12th, 2005, 2:04 am

so it has to be turned in? it doesnt just compress back in?

nope-mx3 · Post by **nope-mx3** » August 12th, 2005, 3:54 am

That`s correct.

Had I seen this before now, I could have told you guys so.

nope-mx3

Gro Harlem · Post by **Gro Harlem** » August 12th, 2005, 6:29 am

get some needle nose pliers and turn it clockwise while firmly pushing it in.

shouldnt need too much effort actually.

oh and make sure your reseviour cap is REMOVED or it'll be trying to pressurize inside of there, making it near impossible to push in.

If it is a stubborn b----, use some visegrips on the very tip of the piston (try not to grab the boot or anything) and then try to turn it and move it inward...once its free-up some it should move a lot easier.

sometimes rust forms on the outside of the piston and cauese it to be a b---- to move in and out

mitmaks · Post by **mitmaks** » August 12th, 2005, 2:45 pm

so rear calipers are operating only with parking brake and retract back in when its released?

jaydog5678 · Post by **jaydog5678** » August 12th, 2005, 6:53 pm

mitmaks wrote:so rear calipers are operating only with parking brake and retract back in when its released?

Yes, our type of calipers are called actuating calipers.

sk8erdude802 · Post by **sk8erdude802** » October 19th, 2005, 2:45 pm

Dont feel bad I destroyed a c-clamp trying to compress one of mine and actually took the thing apart before I found out I had to screw it back in...

Post by **Custommx3** » October 19th, 2005, 3:20 pm

You can rent a universal tool that will turn them in fro Autozone if you have on in your area.

sk8erdude802 · Post by **sk8erdude802** » October 20th, 2005, 8:23 pm

I used the end of a adjustable wrench.

mx3autozam · Post by **mx3autozam** » October 22nd, 2005, 9:43 pm

OMG guys. I'm new to MX3's and know this

Remove the 13mm bolt on the rear and use an allan key to turn it back in

Yoda · Post by **Yoda** » October 23rd, 2005, 9:58 am

mx3autozam wrote:OMG guys. I'm new to MX3's and know this

Remove the 13mm bolt on the rear and use an allan key to turn it back in

This only works if you have the rear calipers designed for the 323. Some of the MX-3s have genII RX-7 rear calipers which is the type being discussed here. These calipers the actual pistion has to be screwed back in instead of having a retracting screw on the back.

There is a third type of rear caliper that I have seen on a few '96 these are worse that the 323 screw retracting type for jamming and not working. Never actually tried to replaced the pads on one of these. The last time I saw one of these 5 years ago they were so far gone that the calipers needed to be replaced along with the pads.