pushing in the front brake caliper piston

[dirtytorque 0]

I need to push one of the front brake caliper pistons in a tad after re-fitting my break pads and disc.

I have done some searches and it looks like i will have to draw some brake fluid off b4 doing this from the reservoir and then once the piston is back in top it back up.

 

 

then once everything is back in place stomp on the brakes a few times to bed everything in???

Anything else?

Does the ignition need to be on through out this procedure?

Do I then need to bleed the brakes after all this also??

 

thanks as always

 

 

Robert.

[Goldie 2]

You shouldnt need to do anything with the fluid if youve just been doing a disc and pad change..

 

You can push the pistons in using a screwdriver as a lever..

[saysomestuff 0]

not sure what the 'drawing fluid off' thing is about, but you can WIND the piston back in with a set of needle nose pliers

[dirtytorque 0]

not sure what the 'drawing fluid off' thing is about, but you can WIND the piston back in with a set of needle nose pliers

 

as per the bentley mate it says..

 

"always remove some brake fluid from the reservoir b4 installing new brake pads.When the caliper piston is pushed back fluid is forced out of the caliperand into the reservoir."

 

and isn't it the rears that need windingin and not the fronts?

 

anyway i tried wedging th piston back in using a g-clamp but its like there is too much pressure to overcome.

[Mark_Storm 0]

anyway i tried wedging th piston back in using a g-clamp but its like there is too much pressure to overcome.

 

I haven't tried changing the discs / pads on the C yet but previous cars I have just pushed the caliper back in with my thumbs. Slow but does work.

 

You can push the pistons in using a screwdriver as a lever..

 

Be careful if you use anything as a lever that you get an even force across the caliper, just pushing it at one point on the caliper can knock it out of alignment.

[Riley 0]

The fronts just need pushing,not turning like the rears. 8)

 

Ive always just undone the fluid resevoir cap (normally below max most cases anyway) and used these with a nice even pressure...

 

 

Neil.

[dirtytorque 0]

thnks chaps.

[Supercharged 2]

Yep, push not turn...

 

Before I had the proper tool I used a G clamp and one of the old pads... turn 1/4 of a turn at a time with the cap off the res... if the brake fluid is near the minimum you shouldn't need to remove any but you will if it's higher... use a pipett or syringe or clean bit of cloth (lint free)

[Toad 0]

I try to do it with the caliper still on the car... put a bar across the back of the caliper and pull it toward you. of course you should only do this if the car is properly secured on axle stands etc.

[dirtytorque 0]

:(

 

this thing has to be seized up.

 

its not budging.

I even bought a caliper piston retraction tool that uses a 1/2 driver.

[Roger Blassberg 0]

try releasing the bleed nipple before pushing the piston in. If that allows the piston to move, it indicates that the flexible hose has collapsed internally and is blocking the flow. Did you notice that the braking was uneven/pulling to one side before you started to strip it down?

 

Best wishes

 

RB

[dirtytorque 0]

No i never noticed any uneven pulling etc.

 

 

Ok even weirder.

 

When I undid the brake nipple screw nothing came out.

the reservoir is about 2/3 full???

 

wot does that mean.

 

I've broken it havn't I.

 

:(

[Supercharged 2]

Sounds fooked but could be a knackered hose as Roger says...

[dirtytorque 0]

wot about driving it the whole way out and then maybe trying to put it back in again?

 

 

I'm strating to think new caliper now.

[Critical_Mass 10]

did you try pumping the pedal to see if anything comes out then? New calipers from GSF are 40 odd quid each. Not too bad.

 

EDIT- that was for rears though.

[Laughingboy 0]

If the Caliper appears seized, before you rush out and replace it just replace the seals as they are very cheap from VAG.

 

Pinch the flexi hose (I use a set of mole grips with some hose pipe over the ends) to block the flow and remove the caliper.

 

Use a foot pump to blow out the piston, the outer dust cover will need to be prised off before it pops out. inspect the piston for any corrosion, depending on the severity you can sometimes remove any light rust with emery cloth but you need to polish it nice and smooth. use some discretion

 

Prise out the old seals and replace with the new ones. the dust cover can be a real shite to do but will go eventually.

 

Sit back and admire your nice new caliper!

[Roger Blassberg 0]

A word of caution, though. If the bore of the caliper is corroded, play safe and get a replacement.

 

Best wishes

 

RB

[dirtytorque 0]

i was just about to have another go at this so thnks for the words of wisdom.

[dirtytorque 0]

Hi.

 

Ok some progress.

I clamped the brake line and took the caliper off.(I should have done this earlier)

 

 

This gave me better access and room to maneuver without worrying about the brake line.

A few gentle taps of the piston with a hammer to re-align it within the caliper and hey presto,I can now re-tract the piston.

I re-attached the caliper back to brake line and then retracted the piston some more. I wanted to see the brake fluid level rise.(I was worried that the brake line had been damaged.).Brake fluid level rose as it should,and no I didn't take it above the max level. :)

 

The down side is that where I had previously attempted to retract the piston the force has somehow bent one of the guide pins.

Also the brake pad housing was pushed off the guide pins with the bolts still on.

 

Does a replacement caliper come pre-assembled with a replacement brake pad housing?

Not sure what to replace and what to salvage.

 

Also how do you guys mate a foot pump or compressor to the caliper to blow out the piston.

I tried the adapter for connecting to a tyre but with little affect.

If I do decide to re-use the caliper then I would like to inspect it internally and then replace any serviceable parts etc as suggested above.

 

thnks in advance.

[Supercharged 2]

Hiya - well your getting somewhere at least...

 

unfortunatly the guide pins come with the carrier (very expensive) and are not available seperatly... you can get the rubber boots tho as a repair kit...

 

I would get the pins from a scrappy - any VW / Seat with those size brakes will do, I know the pins at the rear are different top to bottom but not sure about fronts - bare that in mind tho...

 

Prolly best to get a new caliper too as it's off and maybe new flexi's...

[dirtytorque 0]

ok,thnks

 

the brake size to quote being 280 mm right?!!

[Laughingboy 0]

It can be bit of a fiddle but with a foot pump, I'm lucky as I have a bleed nipple from a mk1 cabby which has a large head that locks nicely into a tire valve thingy. I then put me thumb over the flexi pipe hole. a couple of pumps and hey presto, out comes the piston. If you have an assistant you can easy just hold the thing hard with you hand over the bleed nipple hole and block the other. it doesn't need much. You can do it on the car too if its really tough to remove obviously re-attaching it and pumping the brake pedel but you risk losing masses of fluid and making a real mess too! :lol:

 

As for your pin, I think the same ones are use on the 256mm brakes too but I could be wrong (someone fancy checking etka?) you'll find them on pretty much any VAG motor running Girling brakes on the front.

[Supercharged 2]

As for your pin, I think the same ones are use on the 256mm brakes too but I could be wrong (someone fancy checking etka?)

 

You can't tell as the carrier part number is different but like you I suspect the pins are exactly the same...

[dirtytorque 0]

vdub now sell the guide pins separately.

 

20 odd quid.

I also bought a one man bleed tool thingy so hopefully once the parts come 2morrow I should be good to go. :)

[Supercharged 2]

Ah nice one! - maybe it's just the rears you can't get...