pushing pistons in on brake calipers

GeX

GeX

GeX

Soldato
Joined
17 Dec 2002
Posts
7,043
Location
Manchester
hi. anyone know any tricks for pushing the pistons back in on rear brake calipers. they have to be turned as well as being pushed don't they.

if i lock the end of the g-clamp up and then as i turn the clamp to tighten it - the piston will turn too, yeah? Or is this only really done using the correct tool?
 
depends on the caliper.

on mine (Peugeot 205) I can use a G-Clamp to wind the piston back, but on some others you need a special tool, I know that Euro Car Parts sell piston winding tools - in fact any decent motorfactors should.
 
i'm 99.9% sure these ones need to be wound in, but am just wondering if its worth trying without the special tool or not. not keen on buying one just do this job.. unless they're cheap.
 
Yeah try a caliper clamp. Wipe the piston over with a bit of brake fluid first and just wind it in with the clamp. Although you should be able to do it with a G clamp and bit of metal over the end of the piston to keep it square.
 
I never understood this maybe somebody could explain to me. The pistons surely move in and out freely otherwise the brakes wouldn't work, so how is it you have to wind them in, and how do they come back out without unwinding? :confused:
 
crow bar or ratchet extension bar.

Clarkey said:
I never understood this maybe somebody could explain to me. The pistons surely move in and out freely otherwise the brakes wouldn't work, so how is it you have to wind them in, and how do they come back out without unwinding? :confused:
Click to expand...

the pressure from the disc, pushes them back in, but only a fraction away. so you have to push them back in when you put new pads on.. you then have to pump the foot peddle a few times to get the pistons back out to the disc.
 
Clarkey said:
I never understood this maybe somebody could explain to me. The pistons surely move in and out freely otherwise the brakes wouldn't work, so how is it you have to wind them in, and how do they come back out without unwinding? :confused:
Click to expand...

It's due to the handbrake auto-adjustment mechanism built into the caliper which is essentialy a coarse screw thread that goes into the back of the piston. The screw is free to turn as the piston moves out, but it has a ratchet type mechanism that prevents it turning the other way. This is why you have to turn the whole piston to wind it down the screw thread and back into the caliper. There is enough 'slop' in the mechanism to allow the pads to back off from the disk when you let your foot of the brake.

It's usualy possible to retract a caliper like this by using e.g. a open ended spanner or the end of a pairt of pliers to engage the slots in the piston, but having the proper tool makes the job 100x easier, and is well worth buying if you intend to do your own servicing on a regular basis.
 
i think i'll just the proper tool for it, the car had drums on the back origonally so i've never needed the tool. thanks guys.
 
windback tools are cheap enough and you'll get the use out of them. So many cars need them, so even if you change your car, there is a good chance it will still be needed.
 
On a 200sx rear calliper the tool for swaping disks on an angle grinder works perfectly as a winding tool so this may be worth trying if you've got one.
 
I use the handle of a file, with the wood removed. Tapered slightly so fits great. Do have to have a strong grip on siezed up calipers though :eek:

Deffo get a tool for the job if you plan on doing a few.
 
they shouldn't be siezed - but i didn't see the car they came off. just need to pop into town and get the proper tool. it's just summit ive never needed before, but will do now i suppose whenever i fit new rear pads, be a useful tool to have cos i know one of my mates new car has discs on the back so no doubt he'd wanna borrow it!

any places online sell them, living in a tourist area aint handy for getting decent tools - and i always at bloody work :(
 
For my semi seized rears that need turning at the same time I bought the tool. For my fronts I use my thumbs or (carefully) tyre leavers.
 
[huzeeee] said:
G-Clamp Yo.
Click to expand...
Won't wind a caliper properly though.

Get the tool, it makes the job so very much easier and saves scrabbling around with crowbars and stuff when you do front pads too.
 
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