What is it ?????

[Rey S.]

On the back side of the tach in my 72 is a vacuum valve/solenoid switch of some sort. I wish to replace it with one I am sure will work. It has
two spade type electrical connections and 3 vacuum ports, Of which one appears to be "in" next too the two spade connecters and one "out with a tee hook up". Does anybody know what I am talking about? If so what is it called?
Thanks -- Rey

[Alan S.]

Re: What is it ?????

Hi Rey,
How are you?
The part you describe is the Wiper Door Solenoid Valve Switch.
It controls the vacuum signal to the wiper door relay.
Take a look at UPC 12, Sheet B9 in the AIM.
Regards,
Alan

The port pointed directly away from the 'can' is a vent and originally had a small foam filter on it.

[David J.]

Re: What is it ?????

I have seen it called two things. Tach solenoid or wiper door solenoid. It's purpose is to act as a relay, effectively changing the mechanical movement of an electromagnet to a valve that switches control vacuum to the balance of the wiper door circuit. It's very easy to test. I'll see if I can dig up my schematic.

[David J.]

Re: What is it ?????

Here's a couple of pics which will explain what it is and supposed to do. Very easy to test with a vacuum pump.

[Rey S.]

Re: What is it ?????

Alan ---- I am well and ready for Xmas. Thanks for the info, explains a lot in a few words. So now I am guessing it has nothing to do with the Tach other than some place to hang it!

[Rey S.]

Re: What is it ?????

Hi David -- Yup that's the part I had in ??? Now I just have to find a replacement, Should be a little easier now that I know what is called.
Thanks Rey

[Joe L.]

Re: What is it ?????

Hi David -- Yup that's the part I had in ??? Now I just have to find a replacement, Should be a little easier now that I know what is called.
Thanks Rey

Rey-------

The part number was GM #5638276 but it's long-since GM-discontinued. However, I believe a reproduction is now available. How good they are I do not know.

[Rey S.]

Re: What is it ?????

Joe ---- Thanks for the info. There are a couple of "not the same looking" reproductions out there. Where they are made is a question.

Rey

[Joe L.]

Re: What is it ?????

Joe ---- Thanks for the info. There are a couple of "not the same looking" reproductions out there. Where they are made is a question.

Rey

Rey------


Yes, the "reproductions" are not configured like the originals. However, this is a difficult-to-see part when installed. While the difference in configuration might be an issue for judging, I would think that functionality is the most important thing. Of course, as I mentioned, I do not know if they function properly and are durable.

In a way, I'm really surprised that this part is even reproduced. This is a Corvette-only part and, at that, covers only 5 years. So, if it does work properly, I'd say 68-72 folks are really lucky to have it available, correct configuration or not.

An original is shown above, a reproduction below:

GM #5638276.jpg

[David J.]

Re: What is it ?????

Rey,

Please forgive me if I am too inquisitive here. I do not know the situation you are in with it. Have you tested the solenoid? Many times it will give symptoms of failure only to actually be another component in the circuit. There is also a thread over on CF from someone that actually repaired his.

If you do need another one, I have had good success over the years on that auction site obtaining these at a decent price. I currently have 3 extra ones in my spare parts collection including a NOS one.

[Rey S.]

Re: What is it ?????

Hi David,
Thanks for the picture. I found what looks like an exact replacement listed for 90$ over at Volunteer Vette. For me that started out to be the good news. The bad news is that they said theirs was made in China and they have no clue as to reliability and they been out of stock for over a year and have no idea when or even if they would get any more.
So off to Zip and get one of the "don't look the same" replacements also made in China, at least they are only 1/2 the price of a (?) real one. I want to replace it as I don't want to deal with an electro/mechanical part that's 44 years old and been subject to a lot of environmental issues leaving reliability in question. I thank all the members that responded with a lot of info on this item.
Rey

P.S. David -- What is the "CF auction" site you referenced in your reply?

[Jim S.]

Re: What is it ?????

Rey ,

There is a "Twice the Price" alternative on Flea bay :along with others @ $165.00
1968,69,70,71,72 Corvette Door Solenoid GM Part # 5638276

You might also try a PM to Peter Lindahl to see if he has one ,

Jim

[Patrick H.]

Re: What is it ?????

I want to replace it as I don't want to deal with an electro/mechanical part that's 44 years old and been subject to a lot of environmental issues leaving reliability in question.

Given the sheltered life that this solenoid leads, and the quality of repro parts, if yours tests good I would virtually guarantee it will last another 44 years with no issues. I would not guarantee that for a new one. Many original ones from under the hood still work fine, and they're subjected to far worse environments.

[David J.]

Re: What is it ?????

Given the sheltered life that this solenoid leads, and the quality of repro parts, if yours tests good I would virtually guarantee it will last another 44 years with no issues. I would not guarantee that for a new one. Many original ones from under the hood still work fine, and they're subjected to far worse environments.

Sounds like the voice of experience. Very sound advice.

Although I'm new to this forum, I've been around vacuum components for quite a while. If this is not allowed here, forgive me for this and I'll remove it. I've been rebuilding wiper door safety valves, and headlight relays for some time. What I've found is although the Chinese components may look the same, the actual material composition is most often inferior. Additionally, the critical dimensions are also way out of whack. When it comes to close tolerance things like vacuum seals, problems arise.

Many years ago, I gave up on all the import junk. I have found the best way to replace parts is to rebuild the original if at all possible.

P. S. Rey, CF is the Corvette Forum, and that auction site is ebay. (Sorry little CF slang)