Brake master rebuild.

[Rblackadar]

It's time ladies and gents. I'm rebuilding that bad boy master cylinder and I have a few questions. I know with pitting you need to get it resleeved, but how much? It seems really really clean except for a dark stain where one of the pistons sat (varnish maybe)It may be corrosion or it may just be gunk. It also has minor pitting right at the opening, but I don't think the piston seals come near that. I was going to use a carb cleaner dip (Berryman Chem Dip) and let it soak for a few days. That stuff strips rust, paint, skin and everything else off to get a better look at things. I know you're not supposed to use petroleum based products because of the rubber, but this thing isn't going together anytime soon unless the thing is free of said stuff. So would it be Ok to use that if I were to clean the parts after the dip with lets say brake parts cleaner? wait til it is clean and dry and then assemble the new rubber pieces? Please sound off.

[jazzie]

Rblackador,

I work for a brake parts manufacture and under n terms should you use oil based product's no your master cylinder, the rubber will swell and make it useless, Brake fluid is a great cleaning product for taking off paint and other items, if possible soak the unit.Pitting in the cylinder should be repaired as it could lead to leakage down the road.

That's my 2 cents worth...

[Hasbeen]

When I was doing exchange components we had a high tech test for
pitted brake parts, called the pinky test.

Give it a light hone, then stick your finger in there. If you can
feel any pits, sleeve it, otherwise, "she'll be right, mate". My
blokes must have had soft fingers, as nothing ever came back. It's
only a vicious rumor that our customers couldn't come back to
complain, as they were dead. After all, we weren't a hospital.

There are any number of alloy etching materials. We used one that
required the bore to be protected with bungs. I think, from 40 years
ago, it was a phosphoric acid base. Took about 3 minutes.

Hasbeen