Metering Unit Return Fuel Pipe to Tank

[Phil M]

Hi,

My return fuel pipe from the metering unit to the tank has sprung a leak on the bend just as it comes out the MU.  On my car the pipe is a single rubber pipe based pipe all the way to the tank which has an outside material braid. The replacements from Moss and Rimmer are in about six pieces and not all available, my question is can anyone  tell me the  internal diameter of the pipe,  the length needed to run the length of the car, what spec it should be and a suggested supplier.? I have trawled the other threads and down a blank. 

Many thanks Phil

[colin3511]

Hi Phil, 

The complete fuel kit has the return line in it. I would have thought you could purchase just the return copper pipe. Try TRGB. You will need the short flexible pipe to cover the last 8" or so to attach to the metering unit. 

Colin

[elclem1]

5/16 copper pipe.

[Mark Ogram]

The return is 3/16", I am in the process of replacing mine with copper/nickel pipe.

Mark.

[BlueTR3A-5EKT]

21 minutes ago, Mark Ogram said:

The return is 3/16", I am in the process of replacing mine with copper/nickel pipe.

Mark.

+1

Use 3/16" brake pipe for the fuel retun MU to tank.  When  I used to make these I would  put a single bubble flare on each end to ensure the joining rubber tube did not slip off.

 

Cheers

Peter W

Edited May 17, 2019 by BlueTR3A-5EKT

[Waldi]

Mine are 3/16” OD coper as well.

I think the original design did not have clamps, but I installed them at each joint.

This is to avoid the rubber connections leaking fuel,  should pressure build up from a blocked return line.

Waldi

[astontr6]

14 hours ago, Phil M said:

Hi,

My return fuel pipe from the metering unit to the tank has sprung a leak on the bend just as it comes out the MU.  On my car the pipe is a single rubber pipe based pipe all the way to the tank which has an outside material braid. The replacements from Moss and Rimmer are in about six pieces and not all available, my question is can anyone  tell me the  internal diameter of the pipe,  the length needed to run the length of the car, what spec it should be and a suggested supplier.? I have trawled the other threads and down a blank. 

Many thanks Phil

Hi Phil,

I replaced that short piece of pipe when my power unit was rebuilt. The original was a piece of black nylon 66 0.229"/  5.8mm bore pipe. My car is a 1973 CR type and the major part of the pipework is plated steel tube. My metering unit has a screw in fitting on the flange which is a UNF thread but the male part sticking out is a gas pipe thread!!! This is all original and had me fooled for a while??? The male part on the steel return is UNF. you will find that Triumph modified this pipe on later cars as per my set up. I also clipped mine so there is no chance of it coming off. The nylon pipe was obtained from a local hydraulic pipe/fitting company who also supplied the black injector tubes. Make sure you keep the fittings safe.

Bruce. 

[deryckp]

I also sprung a leak from the rubber section over the rear drive shaft. Although the pipe was of considerable age, I also thought that the current ethanol content of the fuel had not helped, so I looked for an ethanol proof replacement. Moss listed a 3/16" bore ethanol proof rubber pipe, but did not actually have any.

I eventually found some at a classic motorbike place in the west country who gave excellent service. I think they were called something like Feked.

 

Cheers,

 

Deryck

[Phil M]

Gents, Thanks for your advice, I have taken it on board and oerdered a complete fuel pipe set ( 3/16 copper) from TRGB, the guys there are always helpful and offer advice from the mechanics as well.

Regards