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Lukens
02-10-2014, 08:02 PM
I've discovered a small leak at the pipe connection to the tank. More of a "weep" than a leak, but enough that I smell fuel in my garage. I've only crawled under the car on jack stands, so I haven't had the best access to it. However, I was able to get a 1/2" wrench on the compression nut and found it to be too big. Before I really booger something up, a few questions:
What size is that nut?
What size is the pipe?
Is there a ferrule on the pipe?
IF I get the nut to move, am I wasting my time trying to tighten the fitting more?
I'm thinking the best fix would be to break the fitting apart, cut the pipe below the ferrule, and put a new ferrule on it. That's assuming I can break the nut loose without damaging the tank connection.
What think ye?

Russ

TR3driver
02-10-2014, 08:35 PM
It's quite possible they aren't all the same, but I'm pretty sure that mine have all been 1/2" AF on that nut. Do you have a post-60K car, perhaps?

Pipe should be 5/16" od (again pre-60K although I don't recall hearing that it changed later). There should be a ferrule, but ISTR it's a special ferrule (like the ones used on the fuel pump and steering box). A modern ferrule may not seal.

I would use a "flare nut" wrench (the kind that wraps around and grabs 5 out of 6 points instead of just two of them), back off the nut and then retighten fairly tight (but not enough to strip anything). If that doesn't stop it (and it probably won't), then it's time to pump out the tank and investigate.

Lukens
02-10-2014, 11:13 PM
Randall, the car's a 45k car. I know what you mean by flare nut wrench. Like I said, I didn't have good access but I could see that my 1/2 open end wrench was just rounding the nut. If all else fails, I might try a basin wrench... unorthodox, but hey. I agree with your idea of backing off and re-tightening. If I can break it loose, some lube might let me get a little extra squeeze on the ferrule. BTW, is a ferrule and an olive the same thing?

TR3driver
02-11-2014, 12:01 PM
BTW, is a ferrule and an olive the same thing?
In this case, at least, yes. Another name is "compression sleeve".

I wouldn't necessarily recommend this, but if all else fails, try wrapping a few turns of string (or better yet, valve stem packing) around the pipe between the nut & sleeve. I've been told that can work at the fuel pump connections (which are also problematic) so it might work here. I went a different route and machined an extended nut that would crush a modern compression sleeve before bottoming in the threads.

TR3TR6
02-11-2014, 12:51 PM
Russ, I had the same problem with the gas fumes and tried tightening it and broke it off. Mine had a small crack in it, it looked like it had been bronze welded at some point. If I had to do it again, I would have cleaned off the area real good and sealed it with JB Weld.

Lukens
02-11-2014, 10:44 PM
Terry, I may go the JB route. I need to get on a lift this weekend and see if I can get the nut off first.
Randall, if I break the nut free, I'll try your idea and put some packing ahead of the existing ferrule.

Thanks for the input.

Russ

Jim TR3A
09-24-2014, 03:26 PM
Terry, I may go the JB route. I need to get on a lift this weekend and see if I can get the nut off first.
Randall, if I break the nut free, I'll try your idea and put some packing ahead of the existing ferrule.

Thanks for the input.

Russ

I had a 78k TR3A fuel smell at the fuel filter input and the union was wet with gas. It was fixed by removing the rubber hose, 5/16 pipe,
pipe nut and ferrule and replacing with a new type hose, motorcycle fuel shut off valve, 5/16 steel brake line, the old pipe nut and a
new 5/16" ferrule from Moss Motors..
Caution... The longer end of the ferrule goes away from the pipe nut. Tighten slowly until resistance is felt then add a little less than
1/2 turn. The union is now dry with no smell.

But, there is still a smell coming from the union at the bottom of the tank to the 5/16 fuel line. It is dry to the touch but smells of gas.
I assume it is the same problem. 9/24/2014.

TFB
09-24-2014, 03:45 PM
In this case, at least, yes. Another name is "compression sleeve".

I wouldn't necessarily recommend this, but if all else fails, try wrapping a few turns of string (or better yet, valve stem packing) around the pipe between the nut & sleeve. I've been told that can work at the fuel pump connections (which are also problematic) so it might work here. I went a different route and machined an extended nut that would crush a modern compression sleeve before bottoming in the threads.

The best valve packing to use would be in my opinion Teflon tape which is Teflon ribbon packing.
Works great for leaking compression fittings.
Tom

mgf
09-30-2014, 11:52 AM
This is just a thought.

My 59 TR3A (TS43919L) had a "weeping" (smelled fumes but no dripping) gas tank which I knew about before I bought it.

Upon removal & close inspection, along the bottom, I observed a few very small weep holes in a straight line along the longitudinal axis of the tank where the moisture (water?) sat in the tank over the years. The 3rd generation of my long time radiator repair shop worked his leading magic on it.

From what you said this is not what you are experiencing but it may have value for others.

mgf

pdplot
10-01-2014, 11:24 AM
This is apparently a longstanding problem with TR3s. When I bought mine new in 1956, it had a gas leak at the tank. I took it back to the dealer in NYC and it was fixed and never leaked again during the 3 years I owned the car.