Master Cylinder 5468309

[Neil S.]

I have recently bought a 69 427 coupe, all in pieces. The previous owner said he owned it since it was almost new, and swears that this master cylinder is the original. It is a 5468309 and has a front stamping of "BA" I've tried my best to spot a julian date code on the bosses with no luck, even with my best harbor freight magnifying glass. Yes I have been through the archives and there is very little evidence that this casting was used for 69, or if the "BA" stamping was used on Corvettes. There was mention of the "BA" possibly being used on Chevelle's. Does anyone know for sure? Joe Lucia, your name popped up a few times about this in the archives, Any info?

[Joe L.]

Re: Master Cylinder 5468309

Neil-----

The '309' master cylinder casting may very well have been used alternately with the more common '346'; both were designed for 1-1/8" bore and are configured similarly. I would not be surprised to find a '309' casting on 1968+ Corvettes with power brakes. However, I don't think you'll ever find one with a "BA" coding used on a Corvette. The "BA" coding was used for 1969 Chevelles with front disc brakes/rear drum brakes and denotes a master cylinder of finished GM part number 5465399. That finished master cylinder would not have been functionally configured properly for a Corvette application and I feel very confident in saying that GM would never have used it for a Corvette application.

[John H.]

Re: Master Cylinder 5468309

Neil -

Note that the "BA" configuration (disc/drum, as Joe pointed out) has a an RPV (residual pressure valve) behind the brass seat in the rear outlet port for the rear drums; if this master cylinder is installed on a Corvette, it will fry the rear brakes.

[Neil S.]

Re: Master Cylinder 5468309

This makes perfectly good sense as he restored a 69 chevelle SS. He must have gotten the parts mixed up. Just curious if you know if this a rare part? It also has the bleeders.

[Joe L.]

Re: Master Cylinder 5468309

Neil------

The only application I can find for that master cylinder, including all other GM cars, is 1969 Chevelle with disc brakes. So, I suppose that would make it fairly rare. It surprises me that it was not used for other 1969 GM "A" body cars with disc brakes, but, apparently, it was not.