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Caliper piston won't retract fully

:
'02 Protege5
So replacing pads and rotors and my rear passenger brake piston can't be pushed in all the way to fit the new pads. It's not seized because I can pump the brakes and see the piston move further out and push it back in until a point where it just won't go back in anymore. The piston sticks out about 4mm past the boot.

Anybody else have this issue? Any ideas?
 
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Mazda P5
This has been discussed. But I would take it apart and rebuild it if you don't want to buy a new one.
It definitely needs to be rebuilt because it's not operating correctly so it's up to you.
 
:
Mazda P5
PCB but all I did was push the Piston back in when I did my brakes, so it could be rust. But I only pushed Piston back in then put in pads. Then pumped them and was good to go.
 

pcb

The Diagram Dude
:
2002 mazda protege 5
PCB but all I did was push the Piston back in when I did my brakes, so it could be rust. But I only pushed Piston back in then put in pads. Then pumped them and was good to go.
The rears aren't supposed to work that way.

Was your P-brake working properly ??



I had to turn the piston to get it to thread back in.

There's these parts inside which aren't included in the rebuild kit.



You can't put a new seal on a sloppy worn out part.

 
:
'02 Protege5
The rears aren't supposed to work that way.
Didn't know there was an adjustment screw haha. Maybe I should've done more research on protege brakes before doing this work. Hopefully this thread will help people in the future from making a dumb oversight. Oh well, just another learning experience I guess.
 
Last edited:
I have always used the adjustment screw to retract the caliper on the rear brakes. One time, the only time I ever brought my car in for the rear brakes, was the also the last time. My calipers were in perfect working order. I was going to the track the next day and thought I'd let a very reputable company (rhymes with Cry-Joint) do my rear pads as I didnt have time to do it myself.
They compressed the piston so much, it blew the seals. Then they call me and tell me I have a defective caliper. I asked if the used the adjustment screw. They said there isnt one and I need to buy a new caliper. I missed the race and lost my entry money as well.
The rear adjustment screw is the proper way to retract the piston in order to get the pads in there correctly.
 

pcb

The Diagram Dude
:
2002 mazda protege 5
When I first got my car (and before joining this site) I took my car in for pads and rotors all around.
I was quoted $250 but it ended up being $740 because "both my rear calipers were seized".

It cost me $500 extra because they didn't know about the adjuster screw.

I do all my own work now.

Here's a link to the factory service manual.

http://www.floptical.net/mazda/

Here's a link to my brake thread where I took apart my rear caliper.
(the pictures got reposted at the end after Photobucket shut me down)

https://www.mazdas247.com/forum/showthread.php?123863018-Rear-caliper-dissection&highlight=
 
Last edited:

pcb

The Diagram Dude
:
2002 mazda protege 5
What i need to know is if i replace the external piston rubber seal will this stop the caliper leaking or will the seal inside the caliper need replacing too?
The external rubber boot is just a dust seal and won't help with the fluid loss.
Part #2 dust seal.



Part #9 is the fluid seal and needs to be replaced.
You may also need a new piston if it is too rough and not sealing fully.



Rock Auto sells a rebuild kit that includes the dust boot, the seal and a second seal for the rotating P-brake attachment point.
(I assume your car is the same as my Protege5)



PS.
Make sure you use rubber grease or the seals will start to dissolve then start leaking.
 

pcb

The Diagram Dude
:
2002 mazda protege 5
This was my rear brake piston a couple of years ago.

I sanded off the rust and greased it and pushed it back in.

It's still working with no seizures or leaks !!

 

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