Trick to getting piston out of clutch master cylinder?

[MattL]

After removing and rebuilding my pedal box, I noticed the grommet at the clutch master cylinder fluid inlet was cracked. Rather than risk having to go through this whole unpleasant process again, I figured I should rebuild the master. I just received the rebuild kit from Rock Auto, and I'm starting the dis-assembly. The circlip is out, along with the pushrod, but I don't know how to get the piston out. I don't see any way to grip the piston to pull it out. Any suggestions?

[Richard]

Hit it on a hard surface and it should dislodge. Make sure and use brake fluid on reassembly. And if there is ANY pitting throw it away.

[Stefan_m2002tii]

the spring should pus it out, clean surfaces to let it out, compressed air can also help to get it out, just remember to catch it in a rag or something, you really dont want to have piston and brake fluid all over the place

[MattL]

Thanks, both of you. I wrapped it in a rag, gave it a few hard whacks on the concrete floor, and out the piston came. I do see some pitting in the form of a line of tiny dimples along the bottom wall of the cylinder. They're really very small. But Richard, I take it from your comment that no matter how small, they mean it's time to replace the whole show. Is that so?

[TobyB]

Given how cheap they are, their availability new,

AND the time involved in changing one,

I'd replace it.

t

[MattL]

Very sound reasoning, Toby. Better to replace it now. Thanks.

Does it make sense to pay a premium for one brand over another? Or are they really pretty much the same?

[Richard]

Those tiny pits are going to increase seal wear. A MC with pits is kinda like a parachute with small holes. I am sure if you go to parts wanted someone will have one with no pits. Good luck.

[MattL]

Thanks, Richard. I've ordered a new master cylinder and a slave cylinder to match.

Pull one thread and the sweater really starts to unravel!