63 Master Clyinder Secondary Cup Part Number HELP!

[Greg S.]

Part number of the secondary cup seal for a '63 master clyinder.
My Corvette parts book unfortunately does not list any parts for a 63 MC let alone this part. Perhaps someone has an older book that might still list this part?

I was on the home stretch of rebuilding my MC when I tore the secondary cup on the backside of the piston during installation into the MC bore. I was fortunate enough to purchase an original OEM Delco-Moraine MC rebuild kit, 5461305, and I'd like to use this kit for the job. I have a bad feeling I just wrecked a non-replaceable part. The aftermarket kits do not use a cup but instead use an O-ring for this seal. Unfortunately the OEM piston has a much larger groove to except this secondary cup and I can't find an O-ring to replace it. Suggestions?

If anyone can supply this part number it would be greatly appreciated. Or better yet does anyone have a cup they could sell me??????
Thanks.

[John D.]

Re: 63 Master Clyinder Secondary Cup Part Number HELP!

Greg, Go to NAPA and ask for 393 master cylinder kit. It has the works in it. But it doesn't have the cover gasket. Long Island has that though #52-20A.
Raybestos has/had a nice kit MK393. That's the kit we used when my 63 MC was rebuilt in 2006. JD