67 master cylinder

[John H.]

Re: 67 master cylinder

Norris -

That's true for passenger car applications of the era, but not for the '67 Corvette, which used the "DC"-stamped 509 master cylinder for both manual and J50 power brakes. Passenger cars with manual brakes used a rear piston with a deep hole to ensure that the pedal pushrod couldn't fall out and render the car brakeless, and the passenger car power brake master cylinders used a rear piston with a shallow hole to accommodate the (captive) short booster-to-master cylinder pushrod. The "DC"-stamped 509 '67 Corvette master cylinder used a "deep-hole" rear piston for both manual and J50 power brake applications.

[John H.]

Re: 67 master cylinder

Gary -

The '67 Chassis Scoring Sheets show 12 originality and 8 condition points allocated to the master cylinder and cap; I don't know what the split is between the cylinder and the cap, but you shouldn't get a total deduct for the cylinder portion (5 dimensions of originality), which would still entitle you to the allocated condition points.

[Jerry Clark]

Garys M/C Problem

Garys M/C is a 509 with a 1" bore. It was correctly bench bled however nothing will bleed this system on the car, not gravity, pedal pressure, vacuum or reverse bleeding will force fluid through the M/C .
By accident, (I hate to admit), I discovered that, with the pedal partially depressed, the M/C can be reverse bled with minimal results but that is the only way that any fluid will pass through this system.
The generic M/C bled instantly.
I believe the rebuilder has botched the sleeve insertion. I have successfully added a booster to a Non PB M/c on many occasions with no problem.
I would like to resolve this situation for Gary prior to Orlando but have no spare 509 either known to be good or otherwise at this point.
jer

[Norris W.]

Re: 67 master cylinder

Gary, if you're that concerned, White Post sent the last several MC's I sent them back out the same day they rec'd them. If you next day it to them on Monday, they'd likely ship on Tues, and you could have back by Wed. You'd probably blow an extra 30 or 35 bucks on all that shipping, but it is do-able.

[Jeff Bratton]

Re: needing 507 with dc stamp

i needing a 509 with DC stamp if any one have one please e mail off boards Sjeffharley@aol.com Thanks

[Craig S.]

Re: 67 master cylinder

I knew between Joe and John the correct information would surface!....Craig

[Gerry Proctor]

Re: Uh oh. You know what goes after your memory?

O.K., you're not having memory problems. For both the 1" and the 1.125" master cylinder castings there are different secondary piston well depths. A shallow one for the PB applications and a deep well for the non-assist but, as Joe Lucia wrote, the correct secondary piston would depend on the intended application and you don't always get the right one from even reputable rebuilders. Both 346 and 509 cylinders had applications beyond the Corvette. When I got my brass-sleeved 509 cylinder it had a shallow pushrod well which won't work on a non-assist car. I had to replace the guts right off the bat.

If you go to Stainless Steel Brake Corps Internet site, you can find the four different rebuild kits that cover the power and non-assist applications for both the 509 and 346 cylinders.

So, in theory, if you had a non-assist secondary piston on a power brake application I can certainly see where you would have problems since you'd be missing about an inch of piston stroke. But you'd have the resistance being offered by the power booster to make it hard to tell that your pressing on the pedal wasn't accomplishing anything.

[Norris W.]

Re: Uh oh. You know what goes after your memory?

Thanks Gerry. I thought I remembered it as a Corvette issue from the past. My 69 L88 has power brakes (J56 mandatory of course) and my 69 L89 has manual. I was almost sure I ran into the piston problem with White Post when doing one of these cars in the late 80's, but I can't remember stuff from the late 90's anymore, so late 80's is gettin' REAL foggy now.

[Craig S.]

Re: Uh oh. You know what goes after your memory?

Gary - thx for the tip on SSBC for a supplier of the kits. I have a good kit from Bendix, but it doens't give the inboard piston, and I have some pitting. I have my original delco parts but I would rather install new and unpitted parts..Craig