69 Master Cylinder Casting No

[Dick Bottis]

I have a 69 L68 coupe with P/B that needs a new master cylinder. I originaly planed on rebuilding it but when I broke it down it was in much worst shape then I thought. A lot of rust and build up and I'm not sure if it can be rebuilt. I have been watching on E-bay and have seen a lot of corvette master cylinders referenced with a casting # 5460346, Al the documentation I have been able to locate says the casting # is 5480346 for P/B. When I look at the casting no on my master cylinder it is hard to tell if the 8 is an 8 or a 6. When I look at the picture on e-bay they also look like the one I pulled off.

Does anyone know if GM used casting #5460346 or could people be reading the number wrong? If so was it used on the corvette?

[Jack H.]

Re: 69 Master Cylinder Casting No

Casting numbers for M-Cyl in '69 were 5480346, pwr assy, and 5455509, manual assy. YES! Often, you'll find slop/flash in the 'fill' of cast number inserts making it very difficult to distinguish '6', '8' and '3' digits....

Since the casting you're looking for was used for a number of years, you also want to make sure the particular master cylinder you purchase is the correct configuration for your car.... Specifically, the front boss should have a semi-circular machined area and pwr brake assy's were typically 'wacked' with a 'PG' code in this machined area. Some very light strikes and difficult to read and some MC assy's have been seen to have 'escaped' the letter code emboss altogether, but the semi-circular machined area should be there (it was dropped altogether in later Shark era years).

Also, on the side of the MC, you should have zinc-plated bleed screws above the brake line ports. These were done away with in later years. Bottom line, it's not just the casting number of the master cylinder you're looking for, it's the full finished configuration you want to wind up with.

This brings up another question.... If you have a correct/original master cylinder, why not send it out 'as is' to a competent rebuilder. He'll tell you whether or not it can be saved (his warranty is on the line if it's beyond useful service). PLUS, most of the major rebuilders have an on-hand inventory of 'cores'. So, if you send them a core that's over the hill, they'll tell you AND offer to swap your core for a rebuildable equivalent, typically at a much more reasonable price then you'll find on eBay, Etc....

[Dick Bottis]

69 Master Cylinder Casting No

Who do you recomend, I have been asking around and no one in my area knows of a good shop that rebuilds them?

[Craig S.]

Re: 69 Master Cylinder Casting No

Go with either White Post Restoration, or Apple Hydraulics. Both will do the profeessional brass sleeving to bring the back to new specifications...you won't be sorry you used one of these outfits....if you plan to have them do all the work I would use White Post, they run a little cheaper on the overall restoration, if you plan to just sleeve the casting and do the rest yourself, go with Apple as White Post only does the complete restoration..... Craig

http://www.whitepost.com

http://www.applehydraulics.com

[John H.]

Re: 69 Master Cylinder Casting No

If you choose White Post (as I have for many parts), tell Billy you want it painted black, and they'll do so - their standard finish is gray.