Fitting a new fuel line

Click on the images to enlarge

On the way back from a recent short break the Mini started using fuel a lot faster than normal. I took a look and could not see any signs of a leak but what I did find was that under the bonnet someone had done an amateur job of hooking the fuel line up to the fuel pump.

I had informed the body shop that I'd fitted a new copper fuel line and that all they had to do was connect the rear end to the fuel tank when they put it back in the boot, and to cut the front end to size, and fit a new flexible hose to the front between the fuel line and pipe.

old pipe in place

If you look at this photo you can see that they just stuck some rubber hose on the pipe, bent it at a right angle and fed the hose down towards the fuel pump and connected that at a right angle too. Although I could not detect any leaks I did notice that there were no clips on either end of the rubber pipe (I put the jubilee on the pump end later) and the rubber pipe had no markings so I could not determine if it was rated for fuel.

The fact that the fuel line now came up into the engine bay almost as high as the carb, then went back down to the fuel pump was not ideal. It had too much play and was moving about when the engine was running. So I decided to nip to my nearest motor factors and purchase some 1/4" rubber fuel pipe and some jubilee clips. I then nipped to the DIY store to buy a pipe cutter. A pipe cutter is an inexpensive tool that can cut pipe smoothly without leaving the jagged edges that a hacksaw would leave. It wont cause a spark and it can be used where room to manoeuvre is limited.

rear pipe in place

Working with petrol can be dangerous so I took extra care. First I jacked up the rear left of the car and placed an axel stand under the jack point lowering the car onto the stand but keeping the car jack in place for extra support. Working under the car I loosened the jubilee clip that was securing the rubber fuel pipe from the petrol tank to the rear end of the copper pipe. With an empty fuel can nearby with a funnel in it, I pulled the hose off the pipe and aimed the fuel into the funnel. When I sensed that the fuel can was getting full I reconnected the rubber pipe to the end of the copper pipe. I only had one fuel can so I emptied the fuel into our other cars petrol tank, which was only half full. I repeated this process three times after which the fuel ran to a drizzle only emptying about a litre of fuel into the fuel can.

draining the fuel tank

Please be careful when working with fuel. It is not the liquid that is dangerous but the fumes that it gives off. Any spillages soon evaporate so don't worry. Make sure you work in a well ventilated area and avoid splashing because its nasty if it gets in your eyes! Wear protective goggles if you have some.

I took the fuel tank cap off to help any remaining fuel flow out of the bottom then I put it back on. I left the back end disconnected and placed the fuel can somewhere safe. I lowered the rear of the car to the floor and chocked the rear wheels before jacking the front left of the car up.

With the front of the car up in the air I disconnected the rubber fuel pipe from the fuel pump and wiped the end with a clean rag. I took a deep breath and blew through the pipe for as long as possible. This flushed out any fuel in the pipe. With the front end higher it helped the fuel run out the back end.

I then left the car for a couple of hours while I ran some errands and had a bite to eat.

a pipe cutter

Now hopefully any fuel left in the pipe would have evaporated by now although there was little risk of the pipe cutter causing a spark. Its still better to be safe than sorry. I screwed the pipe cutter to size and fitted it over the copper pipe and tightened it up. The process is to rotate the cutter through 360 degrees, tighten the knob some more, rotate again, tighten, and repeat until it cuts through the pipe smoothly. It can take a few minutes but it leaves a neat smooth cut with no jagged edges that could damage the rubber hose that you slide over the end of the copper pipe later.

new fuel pipe and clips

You have limited room to work behind the Mini engine and bending copper pipe with your hands in a confined space can be a pain. Relax, take your time and the pipe should bend. You are aiming for a smooth curve so that the pipe bends slowly until it is an inch or two from the fuel pump end piece, at the same height, facing it.

new pipe and clips attached

Next I cut the new rubber fuel hose to size with metal snippers which made a nice straight cut. Sliding it onto the copper pipe in a confined space was a pain but I got about half an inch on. I slid a jubilee clip over the open end and secured the rubber pipe to the copper pipe. I slid the second jubilee clip on next and slid the other end of the rubber hose onto the fuel pump end piece. I secured it in place with the second jubilee clip.

With the front end lowered to the ground once again and the rear end jacked up, I reconnected the rear rubber hose to the copper pipe and secured it in place with the jubilee clip. I'm tempted to insert a fuel cut-off switch either here or in the boot at some point in the future (as suggested to me by someone on the mini forum).

With the car lowered to the floor I tipped the petrol from the fuel can into the fuel tank. I then got into the car, pulled out the choke and turned the engine over. It came to life after about 10 seconds. The fuel pump has to pull the fuel through the pipe from the tank at the back of the car all the way to the engine at the front.

the pipe that was removed

I only had about a litre of fuel so I drove to the nearest petrol station and put a tenners worth in. That barely registered on the fuel gauge and as I drove back the gauge started going down again. I parked the car on the drive with the engine idling and checked everywhere but there appears to be no leaks and the engine is idling ok. It looks like I may have a faulty sender unit in my petrol tank. I'll have to investigate further. At least now I'm happy that I don't have an extra foot of fuel line in my engine bay that was not needed. You can see in the picture how much extra copper and rubber pipe was removed.

Note: The main fuel line running under the car is Kunifer which contains copper but is not pure copper.

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