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I now have a new fuel tank. It fits very well but I am having trouble sealing the fuel outlet. I tried with the original connector with the old olive on the end of the pipe. It has worked well for many years. Now I am having trouble getting it dry and leakproof. I tried a new olive on a spare length of tube and it was very difficult to slide it on. I am not keen to remove the pipe from the car  and work on it on the bench, which would mean breaking open a dry joint further along the line. 

I have enough room to trim off the end of the pipe with the old olive but will  then find it difficult to slide on the new olive. If I polish it  or lubricate will it affect the sealing. I tried some Heldtite sealer on the thread but it seemed to make it harder to turn.  I was not keen to put it on the olive itself.  I may have left it too long while I tried to manoeuvre the tank into place.

How can I make the olive fit and still seal properly ?

Richard & B

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+1 for liquid PTFE.

Had an issue with a pals AC Mechanical Fuel Pump, (Not on a TR) and tightened absolutely to the limit, still had a slight weep.

Liquid PTFE fixed it, and we were down to desperation measures.

John.

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Could it be that the depth of the new fitting is different from the old one and therefore the olive is not seating properly, or perhaps the internal face is a different curvature?

In which case you don't have much choice other than to use a new pipe/olive.

Jerry

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Richard,

you say its a new tank but by the rest of your message it looks like you have added fuel now? - yes?

An old trick was to lay a fine cover of solder over the weeping olive, especially where you can seen the wear marks. (Use a mini file to get the correct shape if needed.) This puts a new surface on the olive, solder is very compliant and will seal petrol.

Don't try it near the tank though if fuels been added !

Bob

 

 

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As Jerry says, I would first check if the olive is deep enough and the counter surface is suitable for on olive (it should have a small conical machined ridge).

Waldi

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This afternoon I managed to remove the old olive and clean up the pipe. The old connector now slides on easily. So I now have a fresh space on the pipe for a new olive. I am reluctant to use a sealer on the actual olive. Last time I tried Heldtite on the threaded part only and there was a leak. Tomorrow I will try a new olive with no sealer and see if by tightening it can be made to match the new threaded outlet shape. If not it looks like sealer all round.  How far should the olive slide down the pipe ?

Thanks Richard & B

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:mellow: I am not a time served fitter or mechanic, but I was always told to never use an olive twice

:mellow: I think a lot of sealing problems come from the confusion between imperial and metric measurements, in particular around the 1/4 in. and 5/16in. These are 6,35mm and 7,93mm and all too easily are replaced by 6mm and 8mm, in one way or another, ‘cos ‘’that will be about right’’

james

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Richard - if the new olive is a nice but moveable fit on the pipe, push the pipe as far as it will go into the outlet socket and then do up the gland nut - this will centralise/maximise all the fit tolerances and it will find it's best fit

Cheers Rich

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14 minutes ago, DaveN said:

Permatex aviation form-a-gasket .no.3 or Loctite 577.

the Permatex is difficult to find but the Loctite 577 I got from eBay. 

I use this stuff either side of traditional gaskets 

not used it with olives tho

 

Permatex 80019. Aviation Form-A-Gasket No 3. (118ml/4oz tin) @ £16.00

https://www.ebay.co.uk/itm/293805633147

 

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I find using a soft sealant on a component intended to seal metal to metal is not a sound practice. The principle of a soft metal olive is it will compress during the first tightening, sealing the gap between pipe and olive. The second “ leak path” is stopped once the olive seats in the female counterpart and is kept under tension. 

Waldi

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55 minutes ago, Waldi said:

I find using a soft sealant on a component intended to seal metal to metal is not a sound practice. The principle of a soft metal olive is it will compress during the first tightening, sealing the gap between pipe and olive. The second “ leak path” is stopped once the olive seats in the female counterpart and is kept under tension. 

Waldi

New olive.  The only sealant might be liquid PTFE.

1/16” minimum protruding pipe beyond olive.

On the fuel pipe it is probably worth having a good 1/2” protruding through the olive so the pipe stands proud of the bottom of the tank.   Will stop the outlet getting any dross from the base of the tank being drawn into the fuel line.
Cheers

Peter W

 

 

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I ordered the Permatex from eBay but it never turned up as they said it was out of stock!! Even the 577 took a while.

The 577 is good on threads and olives.

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I have had problems to previously with fitting and sealing the outlet pipe. I think the following is important to have the best chance.

Always use a new olive.

Ensure the pipe is straight where the olive sits and push the olive along the pipe 1/2 inch or so (see below).

Ensure the pipe goes into the boss so that it protrudes a 1/4 inch or so into the tank itself. This will ensure the olive can get a good grip on the pipe and a firm seating in the boss dome.

Do not overtighten first of all as you may distort the olive. Tighten sufficiently and then check for leaks with enough fuel to cover the outlet pipe in the tank.

This worked for me. You shouldn't need any sealant, it is dry fitting - olives & pipes.

Rob

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4 hours ago, RobTR3 said:

I have had problems to previously with fitting and sealing the outlet pipe. I think the following is important to have the best chance.

Always use a new olive.

Ensure the pipe is straight where the olive sits and push the olive along the pipe 1/2 inch or so (see below).

Ensure the pipe goes into the boss so that it protrudes a 1/4 inch or so into the tank itself. This will ensure the olive can get a good grip on the pipe and a firm seating in the boss dome.

Do not overtighten first of all as you may distort the olive. Tighten sufficiently and then check for leaks with enough fuel to cover the outlet pipe in the tank.

This worked for me. You shouldn't need any sealant, it is dry fitting - olives & pipes.

Rob

+1

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Thanks for all the advice.

This afternoon the sun came out for a couple of hours, so I was out in the garage.  I cleaned off the pipe and used  a new fitting and and a new olive.  I noticed that the pipe was trying to slip downwards, because it was still fitted to the chassis. So while it was still unattached I marked the best position with a piece of plastic tape wrapped round it. As  I finally got the right angle the threaded bolt caught the thread and I was able to turn it by hand twice. The pipe was trying to slip out but I was able to hold it in with one hand up to the taped mark and tighten the bolt with a spanner with the other hand . It did not have to move far to lock the olive and I tried a small amount of petrol. It seemed dry but in the morning I will check again.

All this while it was cold and damp. One day I will need a proper ramp and not just balancing the car on an hydraulic jack  and lying on the garage entrance  half on the damp ground !!

Thanks Richard & B 

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1 hour ago, Richardtr3a said:

One day I will need a proper ramp and not just balancing the car on an hydraulic jack 

 

36 minutes ago, Hamish said:

You need some axle stands for Christmas !!!

+1

It's never a good plan to get under a car which is supported by a jack alone. People have been killed that way. 

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The good news is that the new olive on a clean bit of pipe seems to have worked. It is now dry overnight and I can start fitting the carpets and panels back in. Thanks for the advice and when I start the engine I can back the TR out of the garage and look for the olive that I dropped. It is lucky that I bought a pack of five.

The engine has not started since the summer so I have new petrol and fingers crossed.

Christmas wish list has been adjusted.

Richard & B

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Good news Richard. It is a better repair than trying to use sealant which is basically a fix for something that is not correct (my opinion only off course, no offence meant)

Cheers,

Waldi

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7 hours ago, Richardtr3a said:

The good news is that the new olive on a clean bit of pipe seems to have worked. It is now dry overnight and I can start fitting the carpets and panels back in. Thanks for the advice and when I start the engine I can back the TR out of the garage and look for the olive that I dropped. It is lucky that I bought a pack of five.

The engine has not started since the summer so I have new petrol and fingers crossed.

Christmas wish list has been adjusted.

Richard & B

Great news Richard, that’s good perseverance. Well done.

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Sometimes these problems never go away. The olive is dry and there is no fuel showing.  I tried to start the engine without any signs of life. So I checked a float chamber .

I have been hand priming  the fuel pump and there is nothing coming through. This morning ,if the rain holds off, the rear part of the pipe run will come off for inspection, and maybe the front pipe as well. Where will it all end ?

Richard & B

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