70 Corvette Headlight/Wiper Door Vacuum Relay Valve

[Ronald R.]

Does anyone rebuild these? thanks Ronnie

[Terry M.]

Re: 70 Corvette Headlight/Wiper Door Vacuum Relay Valve

Does anyone rebuild these? thanks Ronnie

Bob Demmel. Find his info in the member's listing from the above drop-downs.

[Edward D.]

Re: 70 Corvette Headlight/Wiper Door Vacuum Relay Valve

You could just replace it with a new NOS valve. Its p/n 5638427 and although it was discontinued some years ago (Joe L could probably tell you when) they come up with regularity on eBay. I bought two last year for reasonable prices, around $75 each as I remember. Beware of the Chinese repros all the parts suppliers sell. Some work OK but others do not. Also the plating of the top diaphragm cover is wrong on the repros.

[Joe L.]

Re: 70 Corvette Headlight/Wiper Door Vacuum Relay Valve

You could just replace it with a new NOS valve. Its p/n 5638427 and although it was discontinued some years ago (Joe L could probably tell you when) they come up with regularity on eBay. I bought two last year for reasonable prices, around $75 each as I remember. Beware of the Chinese repros all the parts suppliers sell. Some work OK but others do not. Also the plating of the top diaphragm cover is wrong on the repros.

Edward------

As far as I can tell, the GM #8638427 was discontinued without supercession in 2010.

Also, the part available from GM for about the last 5-10 years before its discontinuation had a silver plated top section.

[Richard F.]

Re: 70 Corvette Headlight/Wiper Door Vacuum Relay Valve

I recently purchased 4 of them from Full Throttle (this is not an endorsement) they all tested perfect, I installed 3 of them and they all work perfectly. They were priced fairly and Full Throttle was very helpful.

The top plate stamping is slightly different for a 1970 (I believe it may be correct for 1971- up) the plating is the correct type, the color code is too perfect as they relieve the plastic so the color sits in, and it does not have the Delco print on the plastic.

But I'm Happy!

[Ronald R.]

Re: 70 Corvette Headlight/Wiper Door Vacuum Relay Valve

I have those, they are nice but loose points. thanks RDR

[Dick W.]

Re: 70 Corvette Headlight/Wiper Door Vacuum Relay Valve

Edward------

As far as I can tell, the GM #8638427 was discontinued without supercession in 2010.

Also, the part available from GM for about the last 5-10 years before its discontinuation had a silver plated top section.

And the configuration of the now discontinued GM part was incorrect. Very easy to spot when you raise the hood

[Tom A.]

Re: 70 Corvette Headlight/Wiper Door Vacuum Relay Valve

Terry's recommendation of Bob Demel is right on. Bob does great work and is a Texas chapter guy. You won't be sorry.

[Ron G.]

Re: 70 Corvette Headlight/Wiper Door Vacuum Relay Valve

I agree with Terry and Tom they are both correct and Bob Demmel is definitely the guy. However, the only deviation may be in the configuration of the crimping of the two pie plates. Only a trained eye will notice.

[Bob I.]

[Terry M.]

Re: 70 Corvette Headlight/Wiper Door Vacuum Relay Valve

Yes, he is. There was considerable work put into developing an unproved, but undetectable, relay valve. His product is better than original.

Now that I have put that out there I hope he has the materials to meet the demand.

[Patrick H.]

Re: 70 Corvette Headlight/Wiper Door Vacuum Relay Valve

Now that I have put that out there I hope he has the materials to meet the demand.

If not, we'll have to contact his materials guy to make more.