mk3 gti master cylinder repair

[tweed]

hi all. Trying to get the mk3 on the road, it's been sitting for a while and the brakes got spongy, bleed them (twice) and now I'm thinking master cylinder. I've got a seal repair kit. I'm going to attempt to fix it tomo. Anything I should know before I start? any tips or anything?
Oh also it's a 22.2mm bore right?

[Diamond Hell]

22.2mm sounds about right.

Master cylinders are hardly dear.  I'd vote for replacing the unit, rather than just the seals.

Remove it, refit it, fill the resevoir, give it a few pumps, open the closest bleed nipple, give it a few more pumps and leave it with a pipe on the open nipple, emptying into a receiver and go for a cup of tea.  Gravity and time are your friends, more than pumping and ezi-bleeds, or pressure bleeders etc etc. 

Once the fluid's pulled through on one part of the system I would be surprised if you weren't able to bring the others up using the 'normal' two-man bleeding method.

Obviously, make sure the rear compensator valve is opened up when you bleed the rears.

[tweed]

Don't see the point in getting a new unit when it's only the seals that have gone. How much is a new master cylinder? Not one from a scrapyard. Plus 22.2mm is wrong I've got 23mm. so now the car is going to be sitting even longer.

[Wayne]

Much better to replace the cylinder you will often find the piston is pitted when you pull them apart.

[tweed]

it looks fine. How much is a new one? Or where could I find one?

[Wayne]

it looks fine. How much is a new one? Or where could I find one?

Best bet is to try your local motor factors

[tweed]

I can't get the seals I want so new one it is. I found a 24mm bore too  just under £40 not so bad, but everything ads up when you just lost your job.