ReallyWildStuff

What is a good vendor to source a high quality, good looking (anodized?) c.1984 power brake booster?

My '77 Pace Car is running 1984-spec "low drag" front disc calipers and 1984-spec MC with plastic reservoir/power brake booster.

The power brake booster has a hole in the diaphragm, and needs to be replaced.

I still have the original '77 power booster - this was originally fitted with the cast-iron MC. It was my recollection that the later-year plastic MC will not mount correctly to the '77 booster - is that correct? That would make restoring the original unit "unwise".

Thanks

oddball

Unfortunately I don't know the details of your setup, but MBM is the actual US OEM of the cad plated repop boosters with Delco stamping and the vast majority of brake upgrade/swap kits. They may be able to rebuild your '84 unit or have a replacement.
mbmbrakes.com

Pirate Jack is their retail front and uses the building next door. The tech lines for both companies go to the same dude.

joe_padavano

If you have both the old booster and the new M/C, why not just see if they bolt up?

ReallyWildStuff

I was fishing for whether the 77 booster was designed to work properly with the 84 MC from a valving/pressure standpoint.

13 years ago - the combination of '84 "low drag" calipers and 77 MC/77 Booster meant the BRAKE light was always on, also IIRC the front calipers didn't retract all the way. Installing the '84 MC/Booster setup fixed all that. I am wary of mixing and matching brake parts - that's how I killed the last car.

Testing if the 77 booster mates up to the 84 MC is a possible eventuality. I don't really want to disconnect the non-leaking plastic MC from the brake lines if I don't have to, and I didn't want to have to manhandle the 77 booster into the firewall only to determine that it doesn't mate to the plastic MC. IIRC the plastic MC is metric, and the cast iron MC is standard.

I also helpfully painted the '84 Booster Rustoleum gold before installing - so now it is a poor candidate for cadmium plating.

ReallyWildStuff

Sorry for the ignorance but this 77-96 B-body used an 11" booster, is that correct?

oddball

I assume the '84 is a "quick take up" master cylinder. The calipers and MC have to be matched for that feature or else they work poorly - if at all. It can be tough to figure out if a particular part is QTU or not. Neat feature, good idea, generally abandoned though.

The booster doesn't care about QTU. The critical dimensions are mounting ears, diameter of the protrusion into the booster, and the depth of the pushrod hole. You'd need all the parts on the bench, or some good pictures, to verify those. It's hard to find good diagrams, unfortunately.

Most GM boosters are interchangeable, but, no guarantee expressed or implied.

Your old booster would be stripped before plating, so the paint doesn't matter.