I have a 69 Mustang tank in my F1 and the sending unit seal is leaking. I made sure it was in correctly when I put the tank in a couple of months ago. Any ideas on how to seal it? I looked through a bunch of mustang supply places and they all have the same seal I do. I have a Canadian made tank.
are u sure u tightened the three prong nut untill it seated i have installed many of theese no problem ! maybee try a new rubber seal ?
Its as tight as I can get it unless I drive it past the stops. Meaning its at the stops on the sending unit flange. I have a friend that sold a restored 68 Mustang last year and he had the same problem. He put two seals in it and it didnt change anything. IM wondering if theres some sealant I could use on the gasket and install it?
Did you put some grease on the seal before you installed it? I'd maybe give one of those suppliers a call to see if they have seen this before.
Just a quick heads up I have the same tank and had the same problem, if you fool with it enough it will seal properly, believe it or not. I thought I was out of luck for sure but after monkeying around iwth it a while it worked
Every time you take it apart you should install new seal. Get one from Ford and put a little vasoline on it before you install it.
I had the same problem when I installed mine, I had to tighten it a little past those tabs...used a scewdriver and a few love taps from the hammer....no problems...
have you tryed buying the seal from a ford dealer ? i knew a guy who had a resto shop when i needed a seal for my new tank he sent me to ford
The seal is obsolete from a dealer. Hell its almost 40 years old. I asked a local Mustang guy and he told me there all the same. I greased the seal and drove the sealing flange past the stops half a notch and then tapped down on the edges that it slides under to lock. So far so good. I found out my new fuel line was leaking. I tightened it down trying to stop the leak and the clamp ate the hose, so I had 2 leaks. IM thinking the sending unit may have not been leaking or started from the hose now. I had a 3/8 fuel line on it and it wouldnt seal. It set a month or more and was saturated and started dripping fuel down into the sending unit seal. Now IM using a 5/16 line and tightened the sending unit down and made sure the seal is in correctly. Time will tell. Thanks for all the replies.
The seal is still available from Ford. Many cars right through the 80s, and even the Mustangs to 1993, used the same one. Part number is C0AF 9276 A. Tons of stock showing in the warehouses all over the U.S. The kicker is that Ford makes the dealer order them as a package of 10 pieces, even though they are priced individually. So unless the dealer has them on the shelf, they might want you to buy the whole package. cheers Ed N.
I had the same problem with mine. I think part of the problem was that the seal was moving as I was tightening down the lock ring. Someone suggested I use some sealant to hold it in place and that seemed to work. I forget what I used, but it was off the shelf at AutoZone etc and was grey, very sticky and took a long time to dry (if it ever did). I think it was fuel resistent, but not enough to act as a seal. Get a new seal AND a new lock ring. I ordered a new seal and lock ring from American Pony (where the tank came from). They wouldn't let me order just one of each because of $ order miniumums... so I ordered several of each. I went through a few and now have spares for next time i have to open the tank up. Having a few extras laying around won't hurt, especially as cheap as they are... so a bag of 10 from Ford isn't a bad thing. Originally I also had a problem with a leak that turned out to be the nut for the sending unit wire was loose allowing a leak. You can't tighten it with the unit in the tank (the nut on teh inside just spins)
IM at my wicks end! New seal, new fuel line and it leaks again! I thought I had it this time. I had it all greased up and it went together fine. IM ready to throw a moon tank in the bed and say screw it.
Okay its been seven days. Another 2 seals down and a new sending unit. It doesnt leak! but it has a side effect. The truck doesnt run now due to the damn new sending unit not supplying gas! I can fire it up with gas in the carb and it will quit. I tried even using a siphon pump on the fuel line. I can barely get a trickle into the fuel filter. The new sending unti is a cheap POS! The float is a small white plastic ball. My 2 year old could crush it in a second. The whole sending unit is cheaper than the other one I had. The other one has a brass float and a stainless body, everything on it is made better except its leaking on the pickup tube soldered joint. I noticed the fuel sock on the new one is really small mesh wire in plastic housing. The older one is three times bigger. Before you ask yes it has gas, it has about 8-9 gallons in it and I had zero problems with the fuel line and carb before. I primed the fuel into the filter with the suction and started it a few times and its not getting gas. Fuel filter is empty. You can trickle it in if you crank the battery dead or siphon it and then get it started. Now IM looking at buying a third sending unit or buying a whole new setup with a different design. I havent called the mustang supply place yet.
Do you have a vented cap. If not you will have vacuum. You had leak before and did not need vented cap.
I found the problem! The newer sending unit is so cheap the sock/filter screen is loose. It slid up the tube and cut off the fuel supply. It had enough fuel to make you think it should work. This is a crucial thing to check. I will try to get some pics up.
The sending unit is in and the tank is half full of gas no leaks...knock on wood!!! The first picture shows the two floats and how cheap one of the units is made. You can see the cheaper sock in the side. The top sending unit is better made but was leaking around the outlet tube soldered joint. I tried to solder it with flux and silver solder. Didnt work. I swapped the socks as you can see in the picture. The white plastic sock moved around on the tube shutting off the fuel. Not pictured is I made the brass float work on the other wire even though it didnt fit tight. I took some welding wire and made a secure tiedown for it. I hope one person reads this and it helps. Look at how the cheaper sending unit is made. The wire is tac welded and the other is through a hole and even the wire is made better.
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