Phil M Posted May 16, 2019 Report Share Posted May 16, 2019 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 Quote Link to post Share on other sites
colin3511 Posted May 16, 2019 Report Share Posted May 16, 2019 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 Quote Link to post Share on other sites
elclem1 Posted May 17, 2019 Report Share Posted May 17, 2019 5/16 copper pipe. Quote Link to post Share on other sites
Mark Ogram Posted May 17, 2019 Report Share Posted May 17, 2019 The return is 3/16", I am in the process of replacing mine with copper/nickel pipe. Mark. Quote Link to post Share on other sites
BlueTR3A-5EKT Posted May 17, 2019 Report Share Posted May 17, 2019 (edited) 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 Quote Link to post Share on other sites
Waldi Posted May 17, 2019 Report Share Posted May 17, 2019 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 Quote Link to post Share on other sites
astontr6 Posted May 17, 2019 Report Share Posted May 17, 2019 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. Quote Link to post Share on other sites
deryckp Posted May 17, 2019 Report Share Posted May 17, 2019 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 Quote Link to post Share on other sites
Phil M Posted May 17, 2019 Author Report Share Posted May 17, 2019 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 Quote Link to post Share on other sites
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