47-55.1 Mustang gas experts??? How fix this leak..... Not the O'ring

[paintman]

Hey guys! First off Merry Xmas to all of you! So I have you standard Mustang gas tank that keeps on leaking around the bung where you hook up the fuel sender wire. It is not leaking around the flange/O'ring. Is there anyway of stopping this leak without removing the entire sending unit? Or do I have to bite the bullet and remove the sending unit> If so, should I just buy a whole new sending unit or is there a way to fix this leak from the inside? I am not familiar with how this little bung is sealed off. Is there a nut and gaket of some sort on the inside? Thanx!

[dsraven]

pics would reaaaally help. clean it all off and dry it so we can see exactly whats leaking/wet.

merry Christmas to everybody!

[mr48chev]

Looking at this tank unit from CJ Pony (with creds to them for the photo) it doesn't look like there is much of a way to fix a leak around the tube where it goes though the plate.

Possibly a guy could find an epoxy that wouldn't be affected by gas or take it off and solder it.

[dsraven]

if it is leaking around the electrical stud there is not really a fix because the stud on this style of sender simply goes through the sender with a small rubber gasket and then the wire is placed over the back side and it is rivetted. if it isn't rivetted tight enough it could leak around the base of the electrical insulator i suppose. that sucks if you gotta yank it out and replace a new sender.

[paintman]

Yep, it's leaking right around that brass rod that the nut threads onto. It appears to be some kind of rubber insert with the rod in the middle of it.

[dsraven]

like mr 48 says, if it is leaking around the tube there ain't no fix except like he advises. personally I would solder if possible but it may not wanna stick to plated steel.

[dsraven]

it is really just an insulated electrical connection through the steel plate. you don't really have anything to lose by yanking the sender and trying to make some sort of fuel resistant bulkhead connector work. as long as it doesn't interfere with the rest of the mechanism.

like this

https://www.efihardware.com/products...head-terminals

[paintman]

I know whats going to happen...........I'll replace the entire sending unit only to have fixed the original leak, but then have the damn thing leak around the O'ring. LOL!
Big mistake putting a bottom feed Mustang tank in my truck.

What the hell where the Ford engineers thinking????? Take a container and design it to hold a flamable liquid, punch a hole in the bottom, and then expect not to leak.

[cmayna]

If it's the post which the sending unit wire is connected to, that is leaking, then I'd just replace the sending unit. If it's leaking at the 3"+ diameter mounting flange of the sending unit, then you just need to find a way to seal it. If the latter, I assume you are using a O-ring at the flange?

Craig

[Shinysideup]

What is a "standard mustang tank"?

[cmayna]

Originally Posted by paintman

I know whats going to happen...........I'll replace the entire sending unit only to have fixed the original leak, but then have the damn thing leak around the O'ring. LOL!
Big mistake putting a bottom feed Mustang tank in my truck.

What the hell where the Ford engineers thinking????? Take a container and design it to hold a flamable liquid, punch a hole in the bottom, and then expect not to leak.

If it's leaking around the O-ring my question to you is, is it a new O-ring? Did you apply some blue Hylomar gasket dressing to the O-ring first? What tool are you using to tighten the lock ring in place?

No, not a mistake putting in a m00stang tank as long as you can adapt a filler neck which will work with your truck. I've restored 2 vintage m00stangs and have replace tanks for a few friend's rigs.

[cmayna]

Originally Posted by Shinysideup

What is a "standard mustang tank"?

The size of the tank is dependent on the year. 65-68 stangs use a 16 gallon tank. 69-70 use 20 gallon tanks.

[cmayna]

Paintman,
Though I originally agreed to just replace the sending unit if infact it is leaking around the wire post, I have fixed this leak before but it does require removing the sending unit and having good luck on your side, thus why I previously said to just replace it. Just make sure if you are installing a 16 gallon tank, that the sending unit matches the capacity.

[65blackfleetside]

Having a 66 Mustang convertible for 23 years I think I went through 2 tanks and 4 or 5 sending units. This is what I learned:
1. There is a big difference in the quality of sending units and tanks available. I think I found the best sending at Virginia classic mustang. Ethenol destroys these cheap sending units and o rings fast. Not sure if you have non ethenol fuel available in your area? but try and run it as much as possible.

[paintman]

Originally Posted by 65blackfleetside

Having a 66 Mustang convertible for 23 years I think I went through 2 tanks and 4 or 5 sending units. This is what I learned:
1. There is a big difference in the quality of sending units and tanks available. I think I found the best sending at Virginia classic mustang. Ethenol destroys these cheap sending units and o rings fast. Not sure if you have non ethenol fuel available in your area? but try and run it as much as possible.

I here what yer saying! If I remember correctly I bought the sending unit from CjPony. You would think it would last at least a year or two.

[cmayna]

paintman,
Does your m00stang tank have a drain plug? Hopefully it does. If you do infact drain the tank to remove the sending unit, when you go back and put fuel into the tank add just 4 gallons initially (assuming it's a 16 gallon tank). Check your gauge to see if it reads 1/4 full.

[paintman]

Originally Posted by cmayna

paintman,
Does your m00stang tank have a drain plug? Hopefully it does. If you do infact drain the tank to remove the sending unit, when you go back and put fuel into the tank add just 4 gallons initially (assuming it's a 16 gallon tank). Check your gauge to see if it reads 1/4 full.

Actually, It's the bigger, 22? gallon tank.

[cmayna]

Ahhhh, a '70 tank then. Then divide that by 4 to get 5.5 gallons to meet a quarter tank. Just wondering how close the truck's gauge will read 1/4. Stock truck gauges? I assume you then got a '70 sending unit to match the tank?

[DransportGarage]

Originally Posted by Shinysideup

What is a "standard mustang tank"?

The "standard" 65-70 tanks have the sender below the gas line. There are some available that have the sender on top, like this one:

http://www.tanksinc.com/index.cfm/pa...rod/prd502.htm