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TR2/3/3A TR3 weeping at fuel pump, again

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TexasKnucklehead

Jedi Knight
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Recently I had to remove my fuel pump, and re-opened the can of worms issue with weeping fuel at the pump “olive” feed line to carbs (at the pump). I spent significant time re-reading posts pertaining to fixes and wishful thinking fixes. I previously unsuccessfully attempted the “double half compression” fix. Rubber washers, O-rings and gaskets also proved futile. As noted, the engine doesn’t need to be running for this leak because 1) the fuel level in the tank is higher, and 2) the carbs are higher and the fuel in the line can leak down.

The line from the tank is 5/16” and the line to the carbs is ¼”. But the odd thing is the same threaded fitting will fit into either (input or output) fitting of the fuel pump. I replaced the line to the carbs with a 5/16” steel line and used a standard 5/16” compression fitting and no longer have that dribble of gas. Of course, that meant bending the larger line to fit (and more reading posts to find the correct routing).

In my picture you might observe several things. The three left threaded fittings will thread into either input or output of the pump (5/16). The right two have 1/4“ lines, the left two have 5/16” lines. The center two are “original” (left) input and (right) output of the pump. The rightmost is 1/4“ new steel line. The leftmost is 5/16” new steel line.
The differences in the “olives” are obvious, but using the proper sized line with a new compression sleeve seems to work fine. I used the threaded portion that came on the new line. I’m inclined to think I have over complicated this, but know I don’t want gas leaking down the road (before I get it there).

Does this all make sense?
 

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These fittings boggle me. If you under tighten, they leak. If you over tighten, they leak. Sometimes a brand new one leaks, but a worn out old one doesn't. I had the same dribble in the same location you did. After changing lines and olives to no avail, I used a little permatex 512 around the olive...and it worked. Beats me why, though!?

John
 
Yup, everything you've said makes sense. The pump openings are sized to take 5/16" line & nuts; and Triumph used a special nut on the outlet to allow 1/4" line to the carbs. This was a fairly common arrangement back then; I've even seen those special nuts on the wall at my FLAPS.

The reason they are so prone to leak is because modern compression sleeves are a different shape than the originals, which effectively makes them shorter. The originals were flat on the side that the nut bore against, but the modern ones are tapered so they slip inside the nut to some extent. And the threads in the pump fittings aren't quite deep enough to allow the nut to clamp firmly against the shorter sleeves. I've even seen the pump body broken from trying to force the nut in farther.

I solved the problem on my car by turning a nut with an extended unthreaded section at the tip (similar to the hard brake line nuts). It might be that you could accomplish the same thing by carefully filing away the last half thread or so of the original nut; but mine was so badly chewed up that it seemed better to just make a new one.
 
Tex, are you working on your steering column at rhe same time?
 
Working on my steering column? Ha. Ha. Ha. You may recall my car was under 20' of storm surge and all parts need worked on.

I know my restoration plan is probably not the best, but I'm working on whatever suits me at the time, when I have the time. Since I started and ran the engine several months back, I feel like I have to restart it on occasion, to keep it lubed and rust free. Since my engine and chassis is complete, my priority is supposed to be the tub, and only enough to get it blasted and primed, but I get side tracked easily. The tub will be off and on again.

Randall, I see the differences in the old vs new compression fittings, but it doesn't seem the new will not compress far enough -at least not with the 5/16 line and fitting. Perhaps with the 1/4" fitting that is true. Maybe the 5/16 line simply assures the compression fitting is seated better?

I know not, but I'm happy the leak has finally stopped.
 
Tex,

I had the same problem and tried many "fixes" but unsuccessfully. Finally, I simply put a dab of gasket maker (using a small brush) on the side of the olive that goes into the threaded fitting, making SURE not to get any on the front part that goes into the fuel pump (to avoid cloging). Then I slowly and carefully tightened the threaded fitting into place.

That was a year ago, and I've had no leaking since.
 
LexTR3 said:
Tex,

I had the same problem and tried many "fixes" but unsuccessfully. Finally, I simply put a dab of gasket maker (using a small brush) on the side of the olive that goes into the threaded fitting, making SURE not to get any on the front part that goes into the fuel pump (to avoid cloging). Then I slowly and carefully tightened the threaded fitting into place.

That was a year ago, and I've had no leaking since.
Click to expand...

Three chears for the sealant! You just have to be careful to keep it on the outside of the tube.

John

PS...saw there was more flooding in Houston...hope the Triumph stayed dry this time...
 
LexTR3 said:
Tex,

I had the same problem and tried many "fixes" but unsuccessfully. Finally, I simply put a dab of gasket maker (using a small brush) on the side of the olive that goes into the threaded fitting...
Click to expand...

Do you recall what gasket sealant did you use? I too have tried many fixes, including making one "original" olive from two modern day equivalents, and now its time for some sealant.

But I'm thinking that if there is a fuel filter inline between the pump and the carbs, what is there to worry about...

Thanks
 
I have lots of experience with weeping ferrule type compression fittings,and for a quick,usually permanant fix,a couple of wraps of teflon tape does the trick if the ferrule is not very distorted from over tighening.Then,dont over tighten.You can trim excees ,the part on tube not ferrule after wrapping,or precut tape width.
If you get thin 1/2 wide about 4-5 turns, the the thicker 3/4 type will probably be fine with 2-3 turns, streching the tape as wrapping.
have Fun
Tom
 
Mike,

I used Permatex Ultra Black Gasket Maker, but only a VERY SMALL AMOUNT. You don't want any of it to get into the opening of the pipe or the pump. Best to use a small artist's brush to apply it.
 
Hey Ed,Although the gasket maker worked for you,I dont like gasket maker on ferrules,because if you need to take apart again its a mess.
The advantage of Teflon is it is instant result,no dry time,no mess.Wrap,tighten and turn on.
It also has the advantage of not having to be clean,or more important dry.You can even use if fitting is dribbling from leaking shutoff valve.
have Fun
Tom
 
Tom,

You are probably right about that. I would have tried Teflon, but someone else on this forum who has been great help warns against using Teflon anywhere on these cars.

If you use just a little gasket maker behind the olive, and into the ferrule, there's not too much mess. Plus, even if you open it up for some reason, it's possible that whatever is in there will continue to serve if you when you screw it back down.
 
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