Mot...

[dubcheryl]

Hello mk2'ers!
My gti went in for its MOT on Tuesday and failed - as I was expecting! All down to one tyre, exhaust leak and the Brakes (and this is the wounder) all the disks were excessively pitted so a full new set for me then! We have managed to fit the front brakes, hassle free but the rears are proving a little more difficult.
It hasnt failed on the rear calipers being seized so they cant be that bad, but its hard to get them back on, after changind the discs, so I was wondering if there is any way of freeing them up a little?
The boyfriend is doing the work so sorry if I sound a little clueless about whats going on!

[DarnPB]

The brake calipers are self adjusting ones and they work on a screw thread on the piston. The piston needs to be wound back into the caliper and this will create more space for the pads to fit over the new discs.
Being a little old, they may need a little persuasion with a G clamp and a pair of masked up swan neck pliers to turn the piston whilst it is under load from the G clamp. But be carefull not to score the side of the piston or you could cause further problems.

[dubcheryl]

Cool, I know he was doing that with the clamp to get the piston back in, but the calipers also seem a bit seized. Can we unseize them ourselves or should we just not bother as they are ok for the MOT and buy new when the time comes?

[Mew]

Sounds obvious, but the handbrake is definitely off yeah?

[dubcheryl]

Lol yeah it is! It's not me doing the work luckily, if it was however your answer probably would have been, possibly not!

[DarnPB]

Cool, I know he was doing that with the clamp to get the piston back in, but the calipers also seem a bit seized. Can we unseize them ourselves or should we just not bother as they are ok for the MOT and buy new when the time comes?

No, you need to rotate the piston back in whilst applying a pressure to force the piston in. Like I said, the piston is on a screw thread and it adjusts itself out by rotating itself on this thread.

[Ben Lessani]

As DPB is saying, here's a shot of a piston winder in action on a front caliper (fitting guide brakes).