View Full Version : rebuilding master cylinders

23-08-2006, 11:29 AM
As my new car has been sat a while, I think the master cylinders aren't very healthy, as I can't get a pedal, and whenever I try to bleed the brakes, the pedal goes down but nowt comes out the bleed nipples. There AP one's, and I have ordered a couple of seal kits for them, but haven't done one before. Is it fairly straightforward, or is there anything I need to know?

23-08-2006, 03:55 PM
Just replaced the master cylinder on the Golf too. Would love to give some advice bit it kinda went like this:

"UB please order me a new master cylinder"


I fit said item.

UB refits said item.

Job done.

HTH Good luck!

23-08-2006, 07:49 PM
Well luckily it was a piece of piss, 2 nuts and a circlip!

Uncle Benz
23-08-2006, 07:59 PM
I am guessing then that you may have already done the job, Pete. Personally I never fit seal kits to brake master cylinders, as I have to offer a guarantee with my work, and also that any question marks over the condition of the bore will play potentially lethal havoc with new seals running in them. Brakes are a safety critical system. For the price of a complete new cylinder would you chance your life?

23-08-2006, 08:11 PM
Hadn't really thought about it like that tbh, spoke to AP about it and they recommended the seal kit. Haven't actually done it yet, stripped them both down and cleaned everything, new seals should be here tomorow. New master cylinders are around 80 each, and I'd need 2. I'll try the seal kit as I want to take my car out for a bit of fun, if there's any doubt in my mind as to their operation I'll get new master cylinders.

Would you expect the front brakes (4 pots) or the rear brakes (standard) to have the bigger master cylinder?

Uncle Benz
23-08-2006, 08:18 PM
Four pots on front will have larger bore cylinder.

24-08-2006, 09:23 AM
As said in a previous post it is safer and often a more cost effective to change the whole unit.
Seals are not the only part of the unit to need attention and unless you have access to cylinder hones to remove scores and / or corrosion you are probably wasting your time or at least just putting of the inevitable unit replacement for a short amount of time.