how does rear caliper differ from front?

[jcbadger]

Hi all

How do rear calipers differ from front calipers. I've rebuilt front calipers before by blowing out the pistons with compressed air but whats the procedure with rear calipers as I believe they differ in that they are mounted onto screw threads hence why they require a special retraction tool when pushing them back in. Can this same tool be used to pull them out too?

Thanks in advance . JC

[GCA3N]

I have changed both front and rear pads on my cooper and cannot remember the proceedure being any different, well apart from the hand brake needs to be off chaaging the rears so make sure the car won't roll. I removed the resovoir cap and just pushed the pistons in. I am pretty sure that is right It was a while back.

[rawtor51]

The rear piston needs wound back when pushing it in, it wont just push in like the fronts , other that that its simples:thumbs up:

[GCA3N]

The rear piston needs wound back when pushing it in, it wont just push in like the fronts , other that that its simples:thumbs up:

I was sure I didn't do that but I'm getting old so memory is not quite was it used to be , maybe I turned it as I pushed.

[jcbadger]

hi

thanks for the replies - sorry I meant how are the pistons taken out so they can be cleaned up and then reinserted. I think one of mine has seized. On the front calipers to get the pistons out you used compressed air and physically 'blow' them out.

[GCA3N]

hi

thanks for the replies - sorry I meant how are the pistons taken out so they can be cleaned up and then reinserted. I think one of mine has seized. On the front calipers to get the pistons out you used compressed air and physically 'blow' them out.


eh:idunno:

[rawtor51]

if its seized you could have a real hard time getting it out,,

You going to put hose clamps on before you disconnect the brake line, even if you are you will stilll have to blead the brakes again when assembled.

I would just take out the pads and use the pedal to push out the piston, prob the easiest way:thumbs up:

If its really seized, prob easier to get a new calliper.

[Gismo]

To answewr the question, the pad should move outwards with interneal pressure without any turning etc just as if the pads were wearing down, but, given that it's seized then extra force will be required, to help, remove the pad at the seized piston.
You might have to remove the other pad as well, and place something much thicker than the current pad to use as a back up to trying to force the piston out, apply a lot of releasing fluid, like WD40 etc and leave overnight to let it do it's work.
Then, hopefully the piston will loosen with brake pedal application, but, i suspect it's gonna be worse then that, so, you'll probably need to remove the caliper altogether and work on it that way by forcing pressure into the void and moving the piston in and out.
remember to wind in the piston, a set of long nosed pliers will help without the need of the special tool