Fuel line replacement

[Richard the old one]

I need to replace at least one section of my fuel line as it has rusted out and is leaking. What should I use and is it readily available ?

[Carledo]

8mm microbore copper central heating pipe, available from plumbing suppliers everywhere and cheaper than copper fuel pipe from the motor factors! It's also slightly more malleable.

Steve

[Richard the old one]

Many thanks Carledo for the quick answer I will now be able to crack on with the work this weekend.

[sprint95m]

Microbore pipe is popular for this task but I won't use it, instead I use Kunifer (copper nickel) 8mm bore pipe.
Kunifer is much more resistant to fatigue than copper.


You have to consider the fuel hoses too. There are ethanol resistant hoses available (not cheap though at about £12/metre).



Ian.

[tony g]

the fuel hose that resists ethanol etc is SAE 30 R9 NOT R6

Tony

[Richard the old one]

I went out early this morning and purchased 10 metres of 8mm central heating micro bore pipe so I will be fitting that at some point but the weather is not encouraging me to go out into the cold garage.

Currently the plan is just to replace the last section so I think I will be able to secure it firmly to reduce any fatigue problem. I can see that it could be a problem at the front end as there is quite a long length of pipe going up to the petrol pump and it has to deal with the engine movement.

Am I correct to assume that I would have to go to a Motor Factors to get Kunifer pipe?

I only found the petrol leak as a result of checking the rubber connections. It was not sufficient to leave a pool on the floor and I could not smell an petrol.

This whole exercise started because the car puttered to a halt a couple of times and in my attempt to find the problem I have changed all the ignition bits so a was looking at the fuel side. The car will start and sit ticking over for a very long time but when driven it dies after a couple of miles. I am hoping that the problem is that the pump is drawing air as a result of the hole in the pipe and not pulling sufficient petrol when the car is being driven on the road.

[sprint95m]

Am I correct to assume that I would have to go to a Motor Factors to get Kunifer pipe?

Yes.

I expect that a factors catering for HGVs and other commercial vehicles is the best bet for one to have it in stock?




Ian.

[simonhorton]

I took my old fuel pipe off and renewed all of it
It's relatively easy when you get the old pipe off , as you can bend the 3 seperate sections to exactly the same contours of the old pipe and the correct lengths

Good luck
Simon

[Carledo]

I did the same on the Carledo, with me running EFi, I didn't want to risk putting 5+bar through the original steel! I also had to make up and fit a complete fuel return pipe from the fuel rail to the tank. I took the opportunity to replace all the rubber hose with ethanol proof stuff and all new stainless hose clips at the same time.
I used the heating pipe throughout, in the case of the return pipe, securing it to the shell with rubber insert P clips. It's been in place for almost 5 years now with no hint of a problem. I wish I could say the same for the aftermarket adjustable fuel pressure control valve I used, it's got through 3 of these and I got fed up and went back to the non adjustable standard one!
I can appreciate Ian's belt and braces approach with Kunifer pipe but, apart from 1 or 2 specific applications (the pipes feeding Dolomite rear wheel cylinders springs to mind) I think it's expensive overkill. It's also much harder to bend accurately, especially in larger bores.

Steve

[Richard the old one]

I have removed the old rear section which has the leak and have removed the offside wheel, plus the bump stop and moved the rear section of the exhaust to make it easier to get the new pipe in. Tomorrow I will attempt to bend to shape the new replacement pipe and to fit the same. I can appreciate that micro bore copper that I will be using will be a lot easier than doing the job with kunifer pipe.

The rest of the pipe line seems fine and is well coated in waxoil but I will have another look in the fine weather.

Unfortunately the rubber pipe that I have is only R6 so it will be another task to upgrade in the Summer.

[sprint95m]

It's also much harder to bend accurately, especially in larger bores.

That is a good point......when I fitted the kunifer fuel pipe to my car there was no axle in place !
I routed it down the offside so as to avoid being above the exhaust.




Ian.

[Richard the old one]

I am glad to be able to report that I managed to make up and fit the rear section of the fuel line today. Looking at the three sections that make up the fuel line I was starting with the most difficult shaped section. I was glad that I had a tool for bending the copper central heating micro bore pipe. It took some time and thought to copy the shape from the old pipework but when offered up it fitted into all the pipe clips without much further bending. I had started bending the pipe from the tank end and worked my way to the front but with hind sight it might have been better to start where there were two bends close together and to have worked both ways.

I did curse that the external size of the new rubber hose that I was using was smaller than what I was taking out and as a result I had to hunt for some smaller hose clips.

I did check that the engine would run but I have not taken the car out on the road to see if this has cured the cutting out problem. The leak in the old pipe was at a bend on the highest point in the run just above the rear axle. This meant that it did not leak petrol when the car was standing as the hole was higher than the petrol tank. It was a small area that I had missed when I had treated the pipe with waxoil.