caliper piston

[john170277]

will be changing disc and pads the weekend how do i wind the piston in so the caliper goes over new pads
110 hdi 2002

[jasper5]

Three ways you can push the caliper piston back without the correct wind back tool....

1) Get a large flat blade screwdriver and slot it between the pad and the disc and lever the pad away from the disc which will push the piston back.

2) Use a large pipe wrench and slot it over the caliper and squash the piston back (with the caliper off).

3) Use a G clamp and wind the piston back that way.

I use all of these methods depending on how tight the piston is to push back.

[D9406]

The pistons dont have to be wound in but pushed in. No special kit is needed a large screwdriver did the job for me when I did mine recently. One of Jaspers suggestions should do the trick.

[lozz]

Ive got a wind back tool if anyone wants to buy one,

ive only used it once,

cost me £28

id be just wanting the cost of postage,

[Gary406]

i usually take the lid off the brake fluid tank under bonnet as well. and place a rag over the top. in case some over spils but this usually never happens.

you do know that you need a T50 or T55 (cant remember which) torx bit to get the caliper bolts out dont you ?? and it definately needs to be one that can fit onto a 1/2" drive ratchet

i got a set from halfords think they was £25 ..

these are brilliant. these are ones i bought when i changed my pads. without them you may struggle to get the caliper bolt off

http://www.halfords.com/webapp/wcs/stor ... zone=PDPz1

and as for the piton a large screwdriver always works for me. (doing brakes on a 2001 merc clk 220 next week)

[steve_earwig]

The bolts on the calliper carrier on the front were tight as hell when I did mine, that was after the song and dance finding somewhere open to sell us one (bluddy bank holiday weekends)

I guess if you're going to lever the pistons back in do it against the old disk...

Ive got a wind back tool if anyone wants to buy one

I borrowed one of these off my brother. Well, actually, he lent it to me without me asking and I only tried it out to see how it worked - brilliantly. Saves a lot of sweat and potential damaging of stuff.

[lozz]

The bolts on the calliper carrier on the front were tight as hell when I did mine, that was after the song and dance finding somewhere open to sell us one (bluddy bank holiday weekends)

I guess if you're going to lever the pistons back in do it against the old disk...

Ive got a wind back tool if anyone wants to buy one

I borrowed one of these off my brother. Well, actually, he lent it to me without me asking and I only tried it out to see how it worked - brilliantly. Saves a lot of sweat and potential damaging of stuff.

iagree the windback tool saves damaging stuff
altho inever had to use it on the peugeot,

ibought it to wind back the piston on the back of alfa romeo,
stuff like Merc, Ford volvo,. etc defo needs a windback tool as you have to push and turn them in with force withought it
and then theres the risk of winding it back in the wrong way and destroying it,

[jasper5]

I've never had need to use a specially made wind back tool in the 41 years I've been repairing cars.

Yes, I suggested levering the screwdriver against the disc because the OP said he was changing the discs....you can lever the screwdriver between the pad and the piston when you take out the bottom 13mm bolt and swivel the caliper away from the pad a little.

[steve_earwig]

I do agree, it would be overkill on any calliper fitted to a 406, I didn't ask to borrow it (I didn't even know he had it) but I thought I'd give it a go just because I'd never used one. And then I thought of all those times when I've had a real struggle to push pistons back in and worried that I was damaging the disk (especially that Marina I had where the piston was a bit worn and kept jamming 'cos I couldn't push it in squarely enough...)

[teamster1975]

If you're using a g-clamp put one of the old pads over the top of the piston (unless the clamp will fit inside the piston); it saves fouling the face edge & if it's twin pot you can wind both back in at once!
I'll second Gary's suggestion of taking the cap & diaphragm off the master cylinder, especially if the brake fluid has been topped up with the pads worn!

[Doggy]

FWIW I use the wooden handle of my lump hammer to lever the pistons back after swivelling the caliper away from the disc. Works a treat.

(Perhaps it's the implied threat that one might use the other end if provoked that makes the difference).