Correct master cylinder for a 1978?

[Frank G.]

Hi All,
My intent was to rebuild the master cylinder in the 1978 I purchased last February. It was a two owner car with 42,000 miles

I'm not sure if what I have is original. The only numbers I see are "29969" and "MADE IN U.S.A."

If this is not correct then I'll try to find the correct one via ZIP or Ecklers.

Can anyone tell me where the numbers are when looking for a new one. Is black paint correct or Silver?

Any pictures would be worth a thousand words.

Thanks,
Frank

[Rick A.]

Re: Correct master cylinder for a 1978?

An old posting from 2006 that Mr. Hinckley provided an answer:

I don't recognize that 29969 number on the master cylinder - it's not a GM casting number; maybe a Bendix or other aftermarket item? The GM dual master cylinder used from '67 to the early 70's was casting #5455509, with bleeders on it; later the bleeders were removed.

[Edward J.]

Re: Correct master cylinder for a 1978?

Frank, There should be a casting no. 5460346 that is if you have a power brake car. Most of the venders do repro.s that are pretty correct. I know that the repro.s are not dated. maybe you can get it dated? and they are black.

[Joe L.]

Re: Correct master cylinder for a 1978?

Frank, There should be a casting no. 5460346 that is if you have a power brake car. Most of the venders do repro.s that are pretty correct. I know that the repro.s are not dated. maybe you can get it dated? and they are black.

Edward-----


It better have power brakes. All Corvettes from 1977 onward had power brakes as standard equipment.

[Joe L.]

Re: Correct master cylinder for a 1978?

Hi All,
My intent was to rebuild the master cylinder in the 1978 I purchased last February. It was a two owner car with 42,000 miles

I'm not sure if what I have is original. The only numbers I see are "29969" and "MADE IN U.S.A."

If this is not correct then I'll try to find the correct one via ZIP or Ecklers.

Can anyone tell me where the numbers are when looking for a new one. Is black paint correct or Silver?

Any pictures would be worth a thousand words.

Thanks,
Frank

Frank-----


This is an aftermarket master cylinder. It may be any one of several brands, including Delco.

[Frank G.]

Re: Correct master cylinder for a 1978?

Thanks very much for all the information. I understand what I need now. The generic ones are $80.00 which is what I have. The GM / Delco reproduction is $148.00 with the correct #5455509 in black. for another $50.00 they date code it based on the vin #. I'll just stick with GM / Delco since mines a driver.

One other question. The diagram shows a round gasget and a round retainer that will go between the master cylinder and the booster. Mine did not have either. I found the foam gasket (ZIP) but looks like the retainer is not available. Any advice? Do I need it?

Thanks again Ed, Rick, and Joe!

[Joe L.]

Re: Correct master cylinder for a 1978?

Thanks very much for all the information. I understand what I need now. The generic ones are $80.00 which is what I have. The GM / Delco reproduction is $148.00 with the correct #5455509 in black. for another $50.00 they date code it based on the vin #. I'll just stick with GM / Delco since mines a driver.

Thanks again Ed, Rick, and Joe!

Frank------


You don't want the 5455509 as that one is a 1" bore cylinder for non-power brake applications. You want the 5460346 which is a 1-1/8" bore for power brake applications. All 1978 were power brake.

Also, you want one WITHOUT bleeder valves to be correct. These master cylinders did not have a broadcast code stamp on a machined surface at the front of the master cylinder. I don't think that these even had the machined surface as used on earlier master cylinders.

[Joe L.]

Re: Correct master cylinder for a 1978?

One other question. The diagram shows a round gasget and a round retainer that will go between the master cylinder and the booster. Mine did not have either. I found the foam gasket (ZIP) but looks like the retainer is not available. Any advice? Do I need it?

Thanks again Ed, Rick, and Joe!

Frank-----


I think the foam gasket you are referring to is the one that goes between the master cylinder and firewall on non-power brake applications. If it's a gasket with "wings" on either side with bolt holes, that's the one for non-power applications. If it's a round gasket made of regular, non-foam rubber, that is the one that goes between the master cylinder and booster. Is it usable without the retainer? I don't know but I hope so because the retainer is long-since discontinued and, as far as I know, is not reproduced.

[Tom R.]

Re: Correct master cylinder for a 1978?

You want the 5460346 which is a 1-1/8" bore for power brake applications. All 1978 were power brake.

Also, you want one WITHOUT bleeder valves to be correct. These master cylinders did not have a broadcast code stamp on a machined surface at the front of the master cylinder. I don't think that these even had the machined surface as used on earlier master cylinders.

Joe and Frank

To get into the weeds on the 1978 M/C, the front machined surface where brake line inserts was stamped with the broadcast code and Julian date code. Broadcast code for early 78 was DM and later 78 YC. Black paint was semi-flat black...machined areas were untouched and not uncommon to find surface rust on those surfaces.

[Frank G.]

Re: Correct master cylinder for a 1978?

Thanks to all,
No luck in finding the retainer so I'll install without it. The foam gasket is all that I will install. Looks to just keep dirt out and not seal anything.

Frank