need part # 3966704 for 1971

[Ralph A.]

Can someone give me a resource for the vacuum reservoir that is mounted under the drivers side front fender. Mine is spit. I would also like some detail instructions on its removal and replacement.
Thanks
Ralph

[Patrick H.]

Re: need part # 3966704 for 1971

Ralph,

I believe that its a "used parts only" piece. You can check with Corvette scrapyards or used part vendors. I know I see the pieces often at Carlisle.

You may be able to remove and repair yours. Depending on the size of the split/hole, you might think of various options. If I recall it is metal, and some MIG welding or JB Weld might work.

To remove it, I think you will likely need to remove both the driver's side splash shield as well as the driver's side gill. The bolts for it are (I think) accessible from the driver's front wheel well. I think you'll have to drop it down below to remove it. Of course, I spent all day under my car but am not near it now to confirm the details.

Patrick

[Joe L.]

Re: need part # 3966704 for 1971

Ralph and Patrick-----

Yes, the vacuum reserve tank is long-since GM-discontinued and not currently reproduced. Actually, there were 2 different tanks used over the 68-72 period. 1968-69 used tank GM #3926295. This tank has TWO ports. 1970-72 used tank GM #3966704. This tank has THREE ports. Otherwise, the tanks are similar. The later tank was used to SERVICE 68-69 models after the 3926295 was discontinued in May, 1972.

Unless the tank suffers from significant internal or external corrosion, they can be repaired by welding or brazing or, even, the JB Weld method that Patrick also mentioned. The cosmetics of the repair, regardless of the method used, might be slightly imperfect, but full functionality can be achieved. Most of the tank is very hard to see, anyway.

Used tanks can be found on eBay pretty regularly.

[Ralph A.]

Thanks for the help Patrick and Joe

This explains why I can not find in the repo catalogs. I have not removed mine yet and now that I can get to it from the underside I will see where the leak is and if it can be repaired.
Thanks again
Ralph

[David B.]

Re: need part # 3966704 for 1971

Hello Ralph

I have an extra 3966704 vacuum tank. It is in good condition with some piting , mostly on the support brackets. I have sand blasted it, primed with self etching primer and top coated with black semi-gloss paint. I will sell it if you are interested. I am restoring my 71 LT-1 and know what you are going through to find parts.

Dave Becknell