C-2 Gas Sender Seal

[Allan J. Wicklund]

Interesting occurrence! We needed to drain the Fuel Tanks on my friends Airplane to complete it's annual inspection. (We needed access to the internals of the Wings.). So what to do with 40 or so gallons of Aviation fuel. My 67 is almost empty, let's Fill it up with 100+ Octane and use it up. (Normally I only run around with 1/2 a Tank just to minimize the weight). The next day the Seal around the Sender was dripping! Most likely from the Tank being full for the first time since installation last year. It is a Quantas.

I Drained the Tank and dropped the Sender. All looks fine and normal. Reinstall and it Leaked worse! Any thoughts are appreciated. Al W.

[Mike M.]

Re: C-2 Gas Sender Seal

renew the rubber O-ring/seal . coat it with silicone paste to facilitate proper ease of sealing. don't think there is anything in av gas that would have caused the leak but could be wrong. mike

[David Dawdy]

Re: C-2 Gas Sender Seal

I used to put 100 LL in my 67 400hp all of the time with no adverse effect. It sure ran a lot better than the 93 octane option!

[Stephen L.]

Re: C-2 Gas Sender Seal

Make sure the gasket is leaking and not the fittings on the sender itself. The leak is probably just a coincidence with filling the tank.....

[Wayne W.]

Re: C-2 Gas Sender Seal

I have had little luck re installing without a new O-ring. Try a new one.

[Allan J. Wicklund]

Re: C-2 Gas Sender Seal

I'm ordering a new one in the morning as soon as LICS opens up. It just seems to me that there is not enough compression of the rubber gasket. I'll also oreder a new Retainer Ring. Thanks to all! Al W.

[Mike M.]

Re: C-2 Gas Sender Seal

the retainer ring must be centered in the tank's retaining flange. if ot, the o-ring won't get max force. agree with wayne wobble-head that a used o-ring rarely seals. use of silicone paste also helps prevent chaffing of the o-ring. mike

[Joe L.]

Re: C-2 Gas Sender Seal

Allan------

The seal and retainer (cam) are still available from GM under GM #3825206 and GM #3774937. However, if you order them from a GM dealer that doesn't stock them, you will have to buy a package of 10 of each of them. There may be a Chevrolet dealer in your area that does stock them, though, in which case you could just go down and pick them up.

If the cam is not fully rotated into final locking position, there will not be enough compression on the seal to prevent a leak. It's not so easy to achieve full rotation of the cam. The silicon lubricant that Mike speaks of will help. Special tool Kent-Moore #J-23346 will help even more.

[Joe R.]

Re: C-2 Gas Sender Seal

Hi Allan:

Before you take out the leaking unit, dry it carefully and watch to see exactly where the leak is coming from. I have had leaks from the seals on the two terminal posts, and I was able to fix those by carefully tightening the nuts while holding the post with some vise grips to keep it from turning.

One time I also induced a leak while removing the hose because I put too much stress on the soldered seal at the point where the pipe exits the sender plate. That can only be repaired by first removing the sender.

[Allan J. Wicklund]

Re: C-2 Gas Sender Seal

Thanks to everyone for thier responses. I ordered the new rubber Ring and Flange this morning. It will be here tomorrow and installed Weds. As Joe points out, I need to look beyond the obvious. It's 18 Degrees here on Long Island and I need to be out in the garage like I need a Hole in the Head! But, when my car ain't right, I ain't right! LOL I'm going in on the 26 to have my left Hip replaced and this getting uo and down is Tough!!! Thanks to all, Al W.

[Joe R.]

Re: C-2 Gas Sender Seal

Hi Allan:

Good luck working in the cold to diagnose this. If you have compressed air available, that helps a lot to rapidly dry the affected area so that you can watch to see where the leak is. Fortunately, the three suspect areas are fairly well separated (O-ring seal, terminal stud seals, and solder around the pipe exit). In my case it was fairly easy to see the source of the leak.

[Wayne K.]

Re: C-2 Gas Sender Seal

Allen,

Best of luck with the hip replacement. I just wanted to echo what Joe Randolph said. I too thought I had a leak that would require the replacement of the tank seal when if fact it was eliminated by tightening up the two nuts Joe referred to.

Wayne

[Allan J. Wicklund]

Re: C-2 Gas Sender Seal

My suspicion grows! It was just too cold to go at it today. I'll post my findings. Thanks, Al W.

[Gerard F.]

Re: C-2 Gas Sender Seal

Allan,

Hopefully your sender unit is not like the imported one on the left in the picture:


They have a totally different terminal seal mechanism than the original (on the right). It is more like a pressure fit rather than a screw down seal.

I had one on my 67, it lasted about 6 months. One day I noticed a gas smell in the garage and some wetness at the terminals. So I tried to tighten the terminals like one would do on the originals.

That did it, drip, drip, drip in the face. And then I almost took a slug of gas in my haste to siphon the tank. Glad no one was in earshot of the incident.

What a piece of junk. Refurbed my original and put it back on the car. Still works great.

Jerry Fuccillo
#42179

[John H.]

Re: C-2 Gas Sender Seal

In the plant, they soaked the O-rings in a pan of engine oil for a couple of hours before using them to make sure they didn't damage the O-rings during installation.