Fuel sending unit gasket replacement.

Edster

Founding Member
Aug 13, 2000
500
1
19
League City, Texas
I noteiced my sending unit gasket was leaking. So I tried to tighten it and wound up drench in gasoline. I put everything back together (after I got the mess cleaned up!).
I was wondering if anybody has tried using an o ring with any success.
If so what size and thickness was used.
Thanks
 
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The proper seal is an o-ring, a square type, specially resistant to fuel. Just stick it in place with a little grease and install the sender. I'm not sure how you could "tighten" this seal, when installed the retaining ring should be turned to the lock. Basically, it's either installed or it's not installed.
 
Yea, I just did this about two months ago and its a square ring as proviously mentioned but I heard a sad story from my neighbor that you should hear.
The guys brother in law was changing his in their garage at night so he had his light down there with him and as the remaining gas came out it was ignited by the light bulb and he lost his house and car. Sounds elemetary I know but it can and did happen.
 
Yea, I just did this about two months ago and its a square ring as proviously mentioned but I heard a sad story from my neighbor that you should hear.
The guys brother in law was changing his in their garage at night so he had his light down there with him and as the remaining gas came out it was ignited by the light bulb and he lost his house and car. Sounds elemetary I know but it can and did happen.

Yeow! I get really impatient when using an old electric fuel pump to suck all the fuel out of the tank. I also work in well-ventilated places, with fire extingisher, etc. Next time I won't feel so impatient.
 
I am looking for an 'O' ring vice the square one that is currently sold as most are too "tall". This the the reason I am searching for an alternative. Since the currently available gaskets are too tall they tend to roll over when tightening therefore leaking. I've had experience w/ this before not only this car(two gas tank swaps) but a 64 falcon as well. I distinctly remember the gasket being a square 'O' ring but not as tall as what is now available at most Mustang parts places.
 
Smear some vasoline petroleum jelly on the gasket. It will then stick in place and move when you install the lock ring.

Thats some good advice. I was planning on trying some RTV. I had just installed a new one after painting the tank, I filled it with gas yesterday to only find out it leaks! Ruined the paint, just one more thing to add to the list!
 
Are you sure that the retainer or the tank isn't bent or something?

I have heard that the grease trick works well too.

I agree with what was said about RTV. I don't think it will hold up to fuel and will be dissolved.
 
Are you sure that the retainer or the tank isn't bent or something?

I have heard that the grease trick works well too.

I agree with what was said about RTV. I don't think it will hold up to fuel and will be dissolved.

Yes but I believe that the o ring shifted when I installed the sending unit. RTV will hold up enough to act as an "adhesive," long enough to install it correctly, same as grease or vasoline would. Thats my thinking anyway. Ive installed one before with no problems, this newer sending unit came with a different shaped gasket then the previous one, but as long as the seal is good it shouldn't leak
 
I ordered a new gasket from CJ's Pony Parts as they had free shipping if ordered last weekend. I looked at the photos and noticed the gasket had a flat, dull appearance as compared to the gasket that came w/ the tank which was shiny and slick. I imagine the densities were different as well. I reckon this will make all the difference. This situation reminds of the MIL SPEC standard/numbers from my Navy days. Too bad you can't get the same info in the private sector.