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Air in fuel line (from a new member)


New Member
Oct 8, 2022
Country Flag
Hello all. We are trying to get our 1998 Colorado, KZ-TE ready for a long trip to Morocco. It had serious rust issues at the back when we bought it – chassis, anti-roll bar and wheel arch – which, after the initial shock, we got down to sorting out with lots of cutting and welding, sand blasting and painting. So now it’s not looking too bad and passed the mot with a comment of ‘very well maintained car’!!!

We have also had problems starting the engine (cranks for too long a time). Sometimes no fuel gets to the engine at all. We think we traced the problem to a corroded steel pipe (the main fuel line) coming out of the tank. Most of the time there is no fuel leak, but sometimes a small pool of diesel appears under the pipe when stopped. The only way to start the car is to bypass the hand primer on the fuel filter (hand primer doesn’t seem powerful enough when there is too much air in the pipes) and suck the fuel out of the tank using a hand pump, then reattach the inlet hose to the filter.

As an emergency patch to get us back from France, we dropped the tank and reattached the rubber hoses connecting the steel pipes from the tank to the steel pipes on the body (the return steel pipe and the vent pipe from the tank actually broke at the grommet securing the pipes at the tank) and we patched up the main line as best we could to get us home.

Now we are back we want to replace the fuel tank feed pipe and vent assembly hence a new main fuel pipe and return pipe. There are 7 screws attaching the circular assembly to the tank, but we don’t have confidence we can remove these screws because they are so corroded.


  • What happens if we can’t remove the feed pipe assembly? If we have to trash the screws to take it off, will we be able to put the new part in to the old tank, or does it mean a new tank? Very wary about working on a tank full of diesel vapours
  • What other parts do we need? A new tea-bag-like filter comes with the assembly from Roughtrax. Is there a fuel pump in the tank as well?
  • We haven’t found the assembly for the vent pipe (separate circle from the main fuel line and return line assembly) so will keep the original, epoxy patched up metal pipe, as that seems to work at the moment.
  • The rest of the fuel lines up to the engine bay seem ok-ish, so for the moment we will keep the originals
  • Is it possible there is an air inlet also at the hand primer, seeing it doesn’t seem to work too well? We are thinking of attaching clear hoses each side of the fuel filter in the engine bay, and seeing if there is more air on the outlet side.
  • It seems easier to start when we are parked downhill. I’m guessing this is because the fuel stays in the pipes through gravity, the air bubble stays at the high point, and the fuel doesn’t drain back into the tank. Is this logic sound?
  • What are we missing? What advice have you got / experience that will help us out?
We have found some good threads on this forum, but this is our first post.


Mark & Claire


Well-Known Member
Oct 11, 2013
Country Flag
Primer heads can develop leaks on these older motors, as you have listed.
As you suspect fuel is running back, insert a one way valve in the feed hose between filter and pump. Not the complete cure, but a remedy maybe until you can get to the actual root of the problem.
Don't worry about diesel vapours if you are thinking terms of a fire, diesel is not highly inflammable, you would need to heat sufficiently it to get it to catch light, in fact if you throw a match into a puddle of diesel the match will be snuffed.