C4 Master Cylinder

[Pete B.]

My 89 M/C started to leak and needs to be rebuilt, on top of that I took small point deduction for aged finish. It appears that it was painted/coated. It is original and dont want to simply rebuild. Does anybody know what would look original and stand up to brake fluid?

[Joe L.]

Re: C4 Master Cylinder

My 89 M/C started to leak and needs to be rebuilt, on top of that I took small point deduction for aged finish. It appears that it was painted/coated. It is original and dont want to simply rebuild. Does anybody know what would look original and stand up to brake fluid?

Pete-----

VERY few paints will stand up to glycol ester brake fluid. The best I know of are epoxy paints. However, I don't know if you could find one that approximates the color and gloss level of the original finish.

1989 used a one-year-only master cylinder, although it was functionally identical to the 90-91 master cylinders. The original part number was GM #14104889, but it was discontinued and replaced in July, 1989. The currently available master cylinder for your application is GM #10157996. Just how this master cylinder may differ in configuration from the original, IF it differs at all, I do not know.

[Pete B.]

Re: C4 Master Cylinder

Thanks Joe,

I am going to test a few panels to see what i can come up with as far as paint goes. I know the easy way might be to buy a new MC but then where's the fun! I have an old one from a different year I may lightly glass bead it and do some tests.

If anyone else has ideas chime in!

Pete

[Tom S.]

Re: C4 Master Cylinder

I would like to see what others have used to refinish one of these. My 88 could use a little touch up!Tom

[Pete B.]

Re: C4 Master Cylinder

I think I have a lead on a GM rebuild kit, if so i will order it. My 87 is bare cast aluminum (no coating). I have a couple of ideas I'm going to try on the old core I have. I will advise the results.

[Tom S.]

Re: C4 Master Cylinder

My 88 is original and looks like a silver paint on it. Part of it has peeled off and does not look perfect. I would like to know what the paint or coating was? I have thought about trying to paint it with a small brush and silver paint. Anyone do this yet? Tom

[Joe L.]

Re: C4 Master Cylinder

I think I have a lead on a GM rebuild kit, if so i will order it. My 87 is bare cast aluminum (no coating). I have a couple of ideas I'm going to try on the old core I have. I will advise the results.

Peter-----


The original (and, only) part number for the 1987 master cylinder overhaul kit was GM #10074133. It was discontinued without supercession, though.

The 1989 master cylinder repair kit was originally GM #10104487 but it was replaced by GM #10181304 which remains available (for over $200, GM list).

I show that Raybestos master cylinder kit #MK1856 will overhaul either the 1987 or 1989 master cylinders.

By the way, GM never manufactured these master cylinders or master cylinder kits. They were manufactured by PBR. Likely, that's the manufacturing source for the Raybestos kit.

[Pete B.]

Re: C4 Master Cylinder

Thanks Joe for your extensive parts experiance, I got one coming in from an AC Delco distributor. I realize that GM did not build them. It was $122. I was referring to a 87 casting core that I have to try to see how paints hold up and look before I deal with tearing it apart. Its 1 point I lost, figured maybe I can grab it back!

[Joe L.]

Re: C4 Master Cylinder

Thanks Joe for your extensive parts experiance, I got one coming in from an AC Delco distributor. I realize that GM did not build them. It was $122. I was referring to a 87 casting core that I have to try to see how paints hold up and look before I deal with tearing it apart. Its 1 point I lost, figured maybe I can grab it back!

Peter----

The Delco part number for the GM #10074133 kit is Delco #175-623. Is that what you have coming? The 10074133 was discontinued from GM in January, 1998. I don't know when it was discontinued through Delco but I would expect about the same time or shortly thereafter. So, if you found one, that's a good find.

Also, I was partially incorrect about the manufacturing source for the master cylinders. The 1988-96 were manufactured by PBR. However, the 1987 was manufactured by Girlock. They are very similar designs, though.