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MG Midget and Sprite Technical - Fuel line leak

My 1500 midget has developed a small leak in the fuel line near to the fuel tank. I noticed it the other day when it was quite warm and I had been for a half hour drive through heavy traffic. When I got home, there was a very fine mist of petrol (bloody dangerous considering I was smoking at the time. . . better give that up) spraying out under pressure, it stopped after a minute of me turning off the ignition.

I have inspected it today and despite me leaving it running for a fair while, I cant find the leak anymore, it has fixed itself :-s.

Clearly I am going to have to replace the section of fuel line, either from the fuel tank to a rubber section just before it turns upwards toward the engine bay, or a small section and join it with rubbers and jubilees) Do people recommend buying ready moulded sections of fuel line (rather expensive) or making a section with pipe benders etc (I have no experience of this whatsoever)

Also, If I disconnect the metal pipe from the rubber pipe heading upwards from the bottom of the tank, will it p1ss out petrol?

All help gratefully recieved

Dave
d j kirk

I find that a bit odd! Not the leak, more how it has manifested itself!

If your 1500 is standard then it will have an engine driven mechanical pump which will create a suction in the pipe from the tank when the engine is running and a pressurised "spray" from a leak in the pipe would be odd, on the "partial vacuum" side of the pump.
You might get a drip from the pipe depending on how big the hole is, and with the engine stopped there would definitely be a drip from the hole in the pipe, fed by gravity from the fuel in the tank above.

Anyway, if the pipe has rusted through I would replace the whole section and be done with it.
If you don't it may leak somewhere else later.

Just my opinion!

John
JB Anderson

Either of the options that you are thinking of will work equally well (replace the entire metal line with a new one, or cut out and replace only the corroded portion with a new piece of metal tube, making the join with a short piece of rubber fuel line and clamps).

The nice thing about the fuel line is that it is such a simple tube (only one fitting, where it goes into the tank itself, the rest is just tube). Compared with brake lines or clutch, with all of their specially formed flares, this is a good one to learn on.

Use 1/4" diameter tube, and for fuel you can change from the original steel (prone to rust, as you have found, but very low cost), to either copper (really easy to bend, but more costly than steel) or copper-nickel (a little bit more expensive, but as strong as steel and super corrosion resistant).

If you choose to replace the whole thing, then my advice is to remove the current one completely, and use it as a guide while you bend your new one to shape. With a little bit of patience, and some spring clamps or tape, you can work your way along and make a perfect replica (which is nice, if you want to make the new one look "factory").

The only "difficult" part is straightening out the coil of new tube, and using the patience to bend the corners carefully to avoid kinking it (a kink is usually grounds for dismissal, and start over with a new piece).

To avoid kinks, it is wise to make all of the bends with a hand held tube bender (they are cheap, and easy to use, and make your bends look perfect).


hope this helps,
Norm


Norm Kerr

you might need to check about patching in rubber where metal was I think it's OK but it might not impress a MoT tester even if it is allowed

I can't picture the pipe you mean but I expect gravity will apply to its position and whether petrol unloads

be very careful about rubber fuel hoses I've had many fail in the last 6 years, if you use rubber I can only recommend the Goodyear 6mm x 3mm (from Halfords)

many parts at the moment have rubbish rubber
Nigel Atkins

The spraying out of petrol is intriguing. Somehow pressure in the tank would have to exceed the partial vacuum of the pump. This would require a sealed tank and sufficient build up of heat to expand the petrol inside it.You might want to check you have a vented cap.
F Pollock

This thread was discussed between 30/06/2012 and 01/07/2012

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