Both Rear Calipers appear to be seized when trying to change discs

[Stuart B]

Hi,

Audi S3 Quattro standard calipers.

Okay so my brakes were working and handbrake working - I wanted to change the discs and pads with some nice new ones. but I cannot press the caliper pistons back in.

I even bought a £30 lazer tool to push it back, is there a trick to this? the only thing I didn't do was remove cap, but I have stood on a spanner and it is not moving.

Is it worth me trying to press the brake pedal to get it to come out a bit first, or should I just junk them and replace?

Why is nothing any good on this car.

Thanks for any advice.

 

[Amex]

take the cap of the bottle and use something around in order not to spoil over the engine, once the cap is out push the piston with tool and it should go back. They are not sized.

 

[Stuart B]

thanks for your help, I will retry again tomorrow - I will be incredibly frustrated if they are seized, in the past I have only seized a caliper when pushed all the way back in over rust in the 90's, these new discs look lovely.


I have a rough noise from around the haldex end of the near side rear drive shaft, which was part of the reason for changing the brakes at the moment anyway - I also dropped the haldex oil and there was a little less than 275 mm taken out (maybe 200mm) - I only put it in a few weeks ago but lost the crush washer and wondered if it had leaked out - but I don't think that was the noise/vibration. I am pretty sure it is not the wheel bearings.

 

[dusty]

Are you trying to push the Pistons in, some rear caliper pistons screw back have you tried screwing them in

 

[S3-LINCS]

As above you will need a rewind tool mate

 

[Stuart B]

grrrr.

I think I have a rewind tool.

http://www.screwfix.com/p/laser-brake-caliper-rewind-tool-kit-2-piece-set/12572?kpid=12572

that will explain the locating pits are in different places on each caliper, pretty amazed at the strength of them.

so
locate
do up then turn the black winder in, instead of the silver sleeve bit.

Thanks this makes sense.

 

[dusty]

That's the right tool the silver disc with the pins fits against the piston then the two black plates sit against the caliper then use the thumbscrew to wind the piston back in

 

[Gops]

Just wind back in. I made a tool and it worked perfectly!

 

[anthony89]

Be careful winding them back in. You may want to do small turns both ways if they are abit siezed.

 

[scotty_24]

Yeah just had this last month, piston rewind tool, strength and swears required

 

[jojo]

Have you taken the handbrake off? Lol

 

[Stuart B]

Removed the whole Calipers now they don't rotate either way, but operating the handbrake does move them 0.5mm at a time,

both the boots were only connected to the top of the piston and not on the caliper and one was totally split, so I will try and service them if I manage to get the pistons out. might try compressed air to push them out - that can work according to haynes. the bits of piston coming out of the caliper are pretty grubby.

 

[Stuart B]

okay I reckon the last person simply screwed the dirty un-dust seal protected pistons back in to the caliper, got them off using the handbrake mechanism now they are clean they can screw in and out. will wait for new dust boots and caliper seals to arrive before refitting may as well clean and spray them at the same time, one of the handbrake mechanisms doesn't quite return as spritely as the other one - that part is not serviceable though just have to see whether cleaning it makes the difference.

the compressor will only pop it off once past the thread.

 

[S3JACKSON]

You might want to get some new guides and stainless bleed nipples as well.

http://www.ebay.co.uk/itm/191555187170?_trksid=p2060353.m2749.l2649&ssPageName=STRK:MEBIDX:IT

http://www.ebay.co.uk/itm/331631797244?_trksid=p2060353.m2749.l2649&ssPageName=STRK:MEBIDX:IT

 

[Stuart B]

Thanks those bits seem okay, soaking the whole lot in meths at the moment.

I am glad I got the pistons out I thought I had broke the thread after standing on the spanner to try and press it back in.

 

[Stuart B]

Any tips on cleaning the calipers tried meths and even a steam gun just incredibly slow going.

 

[Stuart B]

*** - okay so cleaned and sprayed calipers got service kit. now I cant screw the piston back in.

I can turn it in with no issues if the seal is left out, with the seal in place it feels like it engages onto the caliper thread then just turns as if the inside of the piston is turning - this is both pistons either caliper - I am sure it is because the piston cant get fully past the seal - I will try to clean it again - has anyone tried freezing a piston to make it that tiny bit smaller?

 

[S3Zek]

They tend to cerode badly inside the lip where the dust seal sits in and also under the piston seal, this then pinches the piston like its seized, a good scrape out inside the seatings were both seals sit in and all around the top lip to remove any built up crap then clean the outside of the pistons up with some wd40 and fine wet&dry, a little grease on the piston and the seals and they should be sorted

 

[Stuart B]

Hi Thanks,
got them in today - I cleaned out the seal seats and finally managed to get them in. will fit them tomorrow and then start on the fronts.

I dream that they will screw straight in so I just put in new disks and pads. (yeah right)

I was unsure of the grease to use but managed with brake fluid.

 

[dusty]

When you get to bleeding your brakes you will need a pressure bleeder, as the old school pumping the pedal method seems to damage the master cylinder seals

 

[Stuart B]

I used eazibleed but pedal goes straight to the floor still, so I assume the front will need bleeding now too as I removed the calipers - the fluid has drained. I have new pads and discs for the front too but was going to leave them for next weekend. so guess what the front caliper bleed nipples are rounded and seized. oh my days... so I need some new nipples and will use a stud removal tool to get the old nipples out.

Does anyone know the correct nipples to get?

regarding the pedal pressure - do you think I need to bleed the rears again or will the fact the rear calipers were off mean that there will be no pressure on the fronts?

 

[Stuart B]

Can anyone help? I am looking for new bleed nipples for the ATE 54mm single piston standard S3 front calipers?

GSF reckon they are an M7 but the bolts are bigger than a 9mm but the 3/8in (9.54) socket I borrowed was too big after they have been wrecked by someone with mole grips.

Thanks - or are they normally just buy a bunch and see what fits?

 

[Daniel M]

Sorry to revive an old thread but I’m having a very similar issue with my n/s rear caliper.
Car failed its MOT on a binding brake so I’ve taken it off the disc an free’d up the handbrake mechanism as I suspected this was the culprit.
My issue now is I cannot for the life of me wind the piston back into the caliper. I’ve ran the car for a few minutes, tried my wind back tool with as much force as I can create and it only moves maybe 4-5 mm in either direction. I have noticed the seal/boot has come away a little bit so unsure whether this is preventing the piston from moving.

Photos provided below.

Any help would be appreciated before I replace the caliper.

 

[mephisto]

Hi Daniel,

As above seems the OP had the same issue here as you and as someone mentioned below:

I am about to do this on my NSR caliper with same issue so will report back also good luck let us know how you get on.

They tend to cerode badly inside the lip where the dust seal sits in and also under the piston seal, this then pinches the piston like its seized, a good scrape out inside the seatings were both seals sit in and all around the top lip to remove any built up **** then clean the outside of the pistons up with some wd40 and fine wet&dry, a little grease on the piston and the seals and they should be sorted