(more) 1965 M.Cyl cap gaskets

[Wayne M.]

Been a couple of threads recently concerning master cylinders and caps. Here's one on the cap gaskets; specifically, identify the three NOS pieces shown in the thumbnail pic. Beside them is what's on my non-power brake (disc brake) car.

Checking my P&A30 parts catalogs (Gr 4.651) I see this part # 5462995 as service for '65 Corvette, as well as '64-65 Passenger. The disc brake one shown with the cap is probably # 3871542 (if original '65 MY production) which was replaced by # 3888045 on 1-66.

So I'm guessing that the three # 5462995's are for the "disc brake delete", a.k.a. J61 cars, (316 produced). This part # changed to 5465725 on 3-68, and still shows in my Jan '70 Corvette catalog, but now described as '65-66 Corvette ???

Here's the weird part. I thought that the '65 J61 master cylinder was a carry-over part from the 1964 MY, but none of my catalogs show any gasket for '64 Corvette. 1963, yes, but that was different still, with the thumbscrew cap.

So are these 3 new gaskets also for '64 ? (both power brake and manual). Also, for '65, is the J61 master cylinder the same for PB and manual, except for the bleeder screw ?

Sorry so many questions -- comments appreciated.

P.S. what's the correct installation position of my '65 disc brake gasket ? with the center depression facing fluid (as shown) or flipped ?

[Gene M.]

Re: (more) 1965 M.Cyl cap gaskets

Wayne,

Quote: So I'm guessing that the three # 5462995's are for the "disc brake delete", a.k.a. J61 cars, (316 produced). This part # changed to 5465725 on 3-68, and still shows in my Jan '70 Corvette catalog, but now described as '65-66 Corvette ???

Yes the 65 disc delete is the same as the 64 m/cyl. My 65 drum brake car still has the original m/cyl. and I rebuilt it 20 years ago. It has that type lid seal. I have no knowledge of the p/n.

[Joe L.]

Re: (more) 1965 M.Cyl cap gaskets

Been a couple of threads recently concerning master cylinders and caps. Here's one on the cap gaskets; specifically, identify the three NOS pieces shown in the thumbnail pic. Beside them is what's on my non-power brake (disc brake) car.

Checking my P&A30 parts catalogs (Gr 4.651) I see this part # 5462995 as service for '65 Corvette, as well as '64-65 Passenger. The disc brake one shown with the cap is probably # 3871542 (if original '65 MY production) which was replaced by # 3888045 on 1-66.

So I'm guessing that the three # 5462995's are for the "disc brake delete", a.k.a. J61 cars, (316 produced). This part # changed to 5465725 on 3-68, and still shows in my Jan '70 Corvette catalog, but now described as '65-66 Corvette ???

Here's the weird part. I thought that the '65 J61 master cylinder was a carry-over part from the 1964 MY, but none of my catalogs show any gasket for '64 Corvette. 1963, yes, but that was different still, with the thumbscrew cap.

So are these 3 new gaskets also for '64 ? (both power brake and manual). Also, for '65, is the J61 master cylinder the same for PB and manual, except for the bleeder screw ?

Sorry so many questions -- comments appreciated.

P.S. what's the correct installation position of my '65 disc brake gasket ? with the center depression facing fluid (as shown) or flipped ?

Wayne-------

For some strange reason, GM never cataloged a master cylinder reservoir gasket or diaphragm for a 1964 Corvette. However, they did once catalog a master cylinder repair kit which was applicable to both 1964 and 1965 without power brakes. Since the repair kit contains, among other parts, the master cylinder cover gasket/diaphragm, that pretty much tell us that the part was the same for both 64 and 65----just that there was not a SEPARATE gasket/diaphragm cataloged for a 1964. Most likely, this was an error that never got "worked out" of the system.

As far as the 2 cover gaskets, GM #5462995 and GM #3871542, both being shown as applicable to 1965-66 Corvettes without PB, note that the 5462995 is a Delco-Moraine part number and the 3871542 is a Chevrolet part number. It's possible that they are 2 different part numbers are for exactly the same part. It's very rare that both part numbers would show up coincidentally in the same catalogs, but the "strange circumstances" that resulted in no gasket for 1964 being cataloged might have been somehow at work here, too.