Locking Gas Cap

[Mike F.]

Found this cleaning out boxes. Is this an over the counter part that I can junk or would it have any value to someone? I'm guessing it's from 1975?

[Ken A.]

Re: Locking Gas Cap

GM otc gas cap.

[Bill L.]

Re: Locking Gas Cap

Hi Mike:

I dug out my locking gas cap (It came on my 66 BB Coupe when I bought it 18 years ago --) the cap I have has the exact same numbers on it as yours -- an identical item. I am not sure of the origin -- it is not factory -- that much is true but possibly a dealer item i.e. clearly aftermarket--- Personally, I think they are kind of neat and I use mine (when not getting my car judged ---- :O)

You might take a look at this thread ---

https://www.forums.ncrs.org/showthre...ocking-gas-cap


Regards
Bill

[Joe L.]

Re: Locking Gas Cap

Mike-------


It looks like a GM over-the-counter locking cap, most likely GM #3994340. This one is for 1970-74 Corvette applications as you will note there is no venting hole through to the top surface of the cap. The 1963-69 locking caps had such a through hole. Similar caps were also sold in the aftermarket. However, the GM sourced caps used a key that was embossed "Briggs & Stratton". The otherwise sourced caps may or may not have used such a key.

This cap is missing its gasket. However, a new one can be fabricated from a piece of stock, preferably buna-N material, and affixed using 3M weatherstrip cement.

I do not recommend the use of these caps "on the road" as they usually leak gasoline. However, they are EXTREMELY USEFUL when leaving your car parked unattended at a show or overnight at a hotel when you're away from home. Install the locking cap in these situations and the standard cap while driving. I do it religiously. By the way, for "parked-only" use it does not matter if one uses a 63-69 locking cap or a 70-74 locking cap.

[Ralph S.]

Re: Locking Gas Cap

You can open those caps with a quarter ( Coin ) try it !!!! That was common knowledge back in the day. put it in the key slot and turn it to open.

[Bill L.]

Re: Locking Gas Cap

The cap I have has the same part number on it as Mikes cap but per Joe---the one I have has the vent hole on the top ---

Interestingly enough --- my vented cap has the same small piece of tube showing on the back side that Mikes cap has --- AND the hole on the top ---the hole on the top vents through the tube on my cap....

I noticed the tube is on Mikes cap but no vent hole on the front ---

Also note Per Joe's guidance -- that the key on this one has A988 and the word GAS on one side and Briggs & Stratton on the opposite side----just an FYI --- the key for the gas cap has the same exact channels as the key for the glove box and tire lock on my 66 ----

Regards
Bill

Back of Cap.jpgFront of cap.jpgB&S Key.jpg

[Gary R.]

Re: Locking Gas Cap

Same cap as came on my '72 when I bought the car in Oct 1979. B&S key. I had it on my table at Carlisle for $50 for years and never sold it until 3-4 years ago when someone was going around stealing C2-C3 gas caps in the middle of the day. Sold it in 30 seconds and had guys in line to buy it!

[Joe L.]

Re: Locking Gas Cap

You can open those caps with a quarter ( Coin ) try it !!!! That was common knowledge back in the day. put it in the key slot and turn it to open.

Ralph------


Yes, that can be done BUT:

1) The vast majority of folks out there don't know it;

2) Those that do know it, in most cases would not bother;

3) Even if someone did so, all they'd be able to get away with would be the locking cap with no key and they would not get away with a, perhaps original, standard cap. Also, it would be a lot tougher for someone to remove the locking cap on a show field which is where a lot of original caps "disappear".

[Jim T.]

Re: Locking Gas Cap

I have GM locking gas caps like this on my 1968 (vented) and 1970 (sealed) Corvettes. One Halloween in 1974 in Dallas some one or more than one decided to egg and use tomatoes to damage cars in the apartment parking lot. Tomatoes were found smashed on each of my locking gas caps. I believe the locking gas caps kept the tomatoes out of my gas tanks. I firmly believe the kids were later caught pissing in another apartment dwellers gas tank. That cost them some money.

[Joe L.]

Re: Locking Gas Cap

Same cap as came on my '72 when I bought the car in Oct 1979. B&S key. I had it on my table at Carlisle for $50 for years and never sold it until 3-4 years ago when someone was going around stealing C2-C3 gas caps in the middle of the day. Sold it in 30 seconds and had guys in line to buy it!

Gary------


I've seen NOS examples of these GM locking caps with a B&S embossed key sell for Big $$$$$ on eBay. I've never figured out why, though.

[Joe L.]

Re: Locking Gas Cap

The cap I have has the same part number on it as Mikes cap but per Joe---the one I have has the vent hole on the top ---

Interestingly enough --- my vented cap has the same small piece of tube showing on the back side that Mikes cap has --- AND the hole on the top ---the hole on the top vents through the tube on my cap....

I noticed the tube is on Mikes cap but no vent hole on the front ---

Also note Per Joe's guidance -- that the key on this one has A988 and the word GAS on one side and Briggs & Stratton on the opposite side----just an FYI --- the key for the gas cap has the same exact channels as the key for the glove box and tire lock on my 66 ----

Regards
Bill

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Bill-------

I think the same bottom flange of the cap was used for both the vented and non-vented caps. For the non-vented, the "vent hole" on the flange was non-functional.

[Bill L.]

Re: Locking Gas Cap

Yep Joe --- it looks lie that is exactly what they did with these -----

I need to take your advice and replace the gasket on mine though!!! I still like having it for when I travel ---- and park the car outside overnight --- just a bit of a deterrent ---

But I also like that these are a slice of 60's & 70's nostalgia too!!!! :O)

Regards
Bill

[Mike F.]

Re: Locking Gas Cap

If anyone would like the gas cap, just pay the postage.

[George L.]

Re: Locking Gas Cap

I will take it.

George Linares
418 W. Chestnut St.
Hoopeston, IL 60942

Thanks,
George

[Ray K.]

Re: Locking Gas Cap

These locking gas caps were originally sold over the Chev parts counter as an accessory item. The part number for 1963 -69 is #985919, these do have a vent hole. Mine is in a red, blue , & white Chevrolet box. The accessory number for 1971 - 72 is #994179 which was offered later on under a part number of #3994340 with a catalog application listed as 1971 -74 Corvette.

Ray