Fuel Tank Leak

[Dennis W.]

I had what I thought was leaking differential. It was odd, though, because the leaked fluid was very dark and thick. It turned out that the fuel tank had been replaced and they used roofing tar paper as the insulating material between the tank and the supporting cross members. Gasoline leaked out of the tank onto the tar paper pulling the tar out of the tar paper. This dark, gasoline-tar mixture dripped onto the spare tire carrier running forward to drip onto the differential and onto the floor!

The hose clamps were replaced when the tank was replaced the first time. Stainless screw-type clamps were used (obviously new clamps). Question - What type of clamps should be used?

Thanks - Dennis

[Joe L.]

Re: Fuel Tank Leak

I had what I thought was leaking differential. It was odd, though, because the leaked fluid was very dark and thick. It turned out that the fuel tank had been replaced and they used roofing tar paper as the insulating material between the tank and the supporting cross members. Gasoline leaked out of the tank onto the tar paper pulling the tar out of the tar paper. This dark, gasoline-tar mixture dripped onto the spare tire carrier running forward to drip onto the differential and onto the floor!

The hose clamps were replaced when the tank was replaced the first time. Stainless screw-type clamps were used (obviously new clamps). Question - What type of clamps should be used?

Thanks - Dennis

Dennis------


The original fuel line clamps were all flat steel, spring-type clamps. However, that does not mean that's the only type that will work. Stainless steel screw type clamps should work very well. In fact, if you can't seal the lines with the screw clamps, I can't think of anything else will work better.

[Geoff C.]

Re: Fuel Tank Leak

Roofing tar paper is slang for Asphalt Saturated Felt or Fiber products. In case you did not know, that is what was originally installed on these assembly line. You are right gasoline does dissolve asphalt based products; both are hydrocarbons (i.e. organic compounds). They are however rather impervious to water (an inorganic compound) & apparently accordingly to GM did also act as a sound deadener i.e. anti-squeak. Twenty gallons weights > 120 pounds, and the steel tank all strapped down – not really that massive a mounting system – 2 3/8 bolts + 2 straps. Hmmmn does it really move around & squeak without these. I’ll guess: yes. Personally, I have always thought this mounting on 63 up to 82 Corvettes was scary, but it could be scarier – Z-06 with 36 gallons of 110 unleaded behind your seat.

I still have the GM box with GM part # 6260631 identified by the noun name as “Anti Sqk”. GM group 3.022 long since discontinued. Yes it look just like roofing tar paper with the exception of the parallel lines on one surface (to assist roofers – so they do not have to measure frequently, overlap properly & can cut neat pieces). (PS In the past I have done a couple of roof’s.)

Below is a photo of this over the counter service part. I would not even sell this part; it is just too educational. Well, maybe I’d sell it to my friend Joe, (at GM list from back then) – cause he would never sell it. Or I’ll will it to him – if he becomes indigent & has to domicile under one of those Kalifornia 5 level 10 lane freeway interchanges.

I never kept track of the number of boned out Corvettes these anti squeaks were present upon.) Back then they were just fun parts cars; not garage furniture.

Ask 10 ncrs judges and you may get different opinions regarding:

1. thickness
2. width
3. length
4. number of pieces per gas tank support
5. number of pieces per rear cross member.

I surrender; beats me; makes my head hurt.

[Geoff C.]

1. thickness
2. width
3. length
4. number of pieces per gas tank support
5. number of pieces per rear cross member.

I surrender; beats me; makes my head hurt.

[Joe R.]

Re: Fuel Tank Leak

Geoff,

Could you post that again as I didn't get it the first time.

JR

[Joe L.]

Re: Fuel Tank Leak

Roofing tar paper is slang for Asphalt Saturated Felt or Fiber products. In case you did not know, that is what was originally installed on these assembly line. You are right gasoline does dissolve asphalt based products; both are hydrocarbons (i.e. organic compounds). They are however rather impervious to water (an inorganic compound) & apparently accordingly to GM did also act as a sound deadener i.e. anti-squeak. Twenty gallons weights > 120 pounds, and the steel tank all strapped down – not really that massive a mounting system – 2 3/8 bolts + 2 straps. Hmmmn does it really move around & squeak without these. I’ll guess: yes. Personally, I have always thought this mounting on 63 up to 82 Corvettes was scary, but it could be scarier – Z-06 with 36 gallons of 110 unleaded behind your seat.

I still have the GM box with GM part # 6260631 identified by the noun name as “Anti Sqk”. GM group 3.022 long since discontinued. Yes it look just like roofing tar paper with the exception of the parallel lines on one surface (to assist roofers – so they do not have to measure frequently, overlap properly & can cut neat pieces). (PS In the past I have done a couple of roof’s.)

Below is a photo of this over the counter service part. I would not even sell this part; it is just too educational. Well, maybe I’d sell it to my friend Joe, (at GM list from back then) – cause he would never sell it. Or I’ll will it to him – if he becomes indigent & has to domicile under one of those Kalifornia 5 level 10 lane freeway interchanges.

I never kept track of the number of boned out Corvettes these anti squeaks were present upon.) Back then they were just fun parts cars; not garage furniture.

Ask 10 ncrs judges and you may get different opinions regarding:

1. thickness
2. width
3. length
4. number of pieces per gas tank support
5. number of pieces per rear cross member.

I surrender; beats me; makes my head hurt.

Geoff------


Definitely a wonderful, historic piece. First one I've ever seen. As long as you're committed to keeping it unused, I'm happy with that. Otherwise, I'd be glad to buy it from you (for even more than the old GM list price). To me, the important thing is keeping these old parts "forever young". I've got over 33,000 in the collection now but there's always room for "one more".