rear brake pistons wont go in

669hoff · May 31, 2010

I ve just done the rear wheelbearing and the pads were well worn so i got some new ones.
problem is that i cant get the pistons to go back in far enough to get the pads in.
i ve got a brake piston rewind tool but that doesnt help much as they have got a piston each side on my 200tdi.
i ve been trying to lever them back with a breaker bar, but now im at the point where that doesnt go any further, but i still cant get the pads in to fit over the disc.
i ve done a search but i found a threat for a p38 where you can use a g-clamp.
any help would be greatly appreciated.
Cheers
Seb

David Pye · May 31, 2010

These pistons want to be put back straight, rather than rotated in their bores.

So a g-clamp would do it rather nicely. Probably a G-clamp and a piece of wood large enough to enable you to compress both pistons at once.

David

muddy wheeler · May 31, 2010

Have you taken the top off the resvoier to allow the air to escape.

EeEk · May 31, 2010

they have to be pushed back square on. maybe try 2 levers one at either side of the piston.

Are the pistons rusty ? pump the brakes to push them back out a bit and a clean up with emery tape then they should slide in quite easily

669hoff · May 31, 2010

yeah, i ve taken cap off the reservoir.

the problem is that i cant get a g-clamp or my piston-rewind tool in there because it is a double piston caliper.

David Pye · May 31, 2010

I'm a bit puzzled as to why that is. Surely a large g-clamp and a piece of wood across the heads of both pistons should be able to fit?

669hoff · May 31, 2010

cool i ll try the emery tape now.

V8_Disco · May 31, 2010

loosen off the brake bleed nipple, also put some wd40 on the pistons
are they still shinny and smooth? if they arent they need replacing

669hoff · May 31, 2010

the emery tape worked well on one piston.

i managed to push the other piston back by screwing the caliper back on and pushing it back in with a crow bar.

but here is the next problem, the brake line had a pretty bad kink in it and when we put the caliper back on the brake line cracked. so tomorrow i need to get two new brake lines tomorrow because the other one has a dodgy kink aswell.

thanks for your help guys!

David Pye · May 31, 2010

If you are really unfortunate you will find out that the union between the brake flexi hose and the rigid pipe is seized too, leading to you wrecking that trying to undo it, and having to replace the steel lines all the way under the chassis.

Been there :-(

669hoff · Jun 1, 2010

luckily the union wasn't seized and i got the brake lines off alright. just gave them to a mate at lunchtime who is making me some new ones by tomorrow so it should be all fixed by then

rear brake pistons wont go in

669hoff

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David Pye

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muddy wheeler

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EeEk

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669hoff

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David Pye

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669hoff

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V8_Disco

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669hoff

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David Pye

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669hoff

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