When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Anyone know of a source for master cylinder residual pressure valves. I need one for the rear drum side for my front disk rear drum ‘70 442 master cylinder. I just got it back from White Post with a note on the receipt that it needs one. Why they didn’t just put one in is a mystery. My quick web search only turned up the external types.
I’m talking about the valve in the output port of the master cylinder behind the brass fitting. I think these hold roughly 10 psi in the line when the brake is released.
Unfortunately these are built into the M/C. I can't say that I've ever seen them for sale separately. The reality is that you probably don't need it, but you do need the tapered seat if that's also missing. Might be worth a trip out to White Post to ask them why they didn't put it back in. They should have a source for that sort of part, given that they purchase all M/C rebuilding pieces. Besides, It's a nice drive.
Update: I came across this photo of a Raybestos Element 3 M/C rebuild kit (not for this application, however). Look what's shown in the kit. This is the first time I've ever even seen those parts in a kit. Maybe there's a source.
Good suggestions. I was thinking about calling White Post on Friday. It’s about an hour and a half from me. I’ll look closer at Raybestos kits too. I just got the Master Cylinder back from White Post around 7 PM so I was seeking solutions. I’ll pursue your suggestions.
Good suggestions. I was thinking about calling White Post on Friday. It’s about an hour and a half from me. I’ll look closer at Raybestos kits too. I just got the Master Cylinder back from White Post around 7 PM so I was seeking solutions. I’ll pursue your suggestions.
Thanks
Scott
FYI, our local OCA chapter (Capitol City Rockets) typically does a tour of White post in November. Always interesting stuff being worked on.
The bad news. This was for a reproduction 5470409 master cylinder I bought from Camaro Central and I discovered today that it doesn’t have the brass fittings in the output ports but rather machined “reverse flares” which are integral to the casting. Ugh! That’s why White Post didn’t put one in for the rear port.
Scott, to be honest, I'd run without. Many new M/Cs for drum brake cars no longer have the RPVs. They are less important when the M/C is mounted higher than the wheel cylinders (unlike vehicles with the M/C under the floor). I don't have an RPV in the front brake circuit on my 62 F85 and have had no issues in four years of driving it hard.
I appreciate your reply. Since you haven’t had any issues I’ll run the repro. I’m a bit disappointed by the lack of proper port machining but that’s the nature of reproduction parts.
I appreciate your reply. Since you haven’t had any issues I’ll run the repro. I’m a bit disappointed by the lack of proper port machining but that’s the nature of reproduction parts.
Thanks
Scoo
Where are you in MD exactly? We alternate chapter meetings between VA and MD. The next meeting is Sunday in Ashburn, VA.
I’m in Columbia. I used to go to your show at the Montgomery County Community College. We’re in MD do you meet?
Scott
It varies. Lately in the Glen Echo area. The All-GM show has moved to Ashburn because Montgomery College wouldn't even talk to us about using the lot in 2021.
FWIW, there's the aftermarket inline valves which is what I ran with a late model master cylinder. But since this is a repop MC I assume you're going for stock-appearing?
FWIW I'm thinking the original DISC BRAKE master cylinders did not even have those valves installed in them. Only on 4 wheel drum master cylinders.
I dismantled about 6 original Delco disc brake master cylinders a little over a year ago. I pulled them from cars in a local salvage yard......Cutlass's. 1 '70 "EB"-stamped master cylinder and the rest were '71/2 "BE"-stamped masters. I don't think ANY of them had that/those valves in them. I'm familiar w/the valves as I pulled them from a "CT" and a "DP" drum brake Delco masters recently as well.
Most, if not all, of these master cylinders appeared to be original and not rebuilt.
Interesting observation on the lack of RPV valves on the drum output ports of the stock master cylinders you pulled from disk/drum cars. I’m going to run the reproduction as is based on Joe’s reply and yours. I’m also aware of the in-line valves from Summit and others but would prefer the stock appearance. If I have any issues with the repro, I’ll just go back to the 5470409 replacement GM unit.
I’ve had the car since 1996. Took it to shows at first. Then got the racing bug courtesy of my friend Wayne Shipley. Picked up another 455 and built a 488 and with a Muncie Supercase 4 speed, Moser rear, etc. and ran FAST Class from Englishtown to MIR with the Super Cars folks. http://www.supercarraces.com/oldsrecords.html Now I’m changing it back to stock again.
I was wondering which master cylinder style you are going to use....but I went back and read where you must be using the 5470409 "rectangular" style/shape MC.
