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- Mar 1, 2010
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Replacing the DieselPipes on a 1998 KZJ95 ‘Colorado’
I have been running the ‘95’ for six years and I knew that the diesel pipes were corroding towards the rear where they are not protected by the plastic undertrays.
The pipes are steel with a sort of varnish covering, which was split and peeling off. It was one of those jobs that I intended to get around to one day
.Anyway, while I was working on replacing the diesel tank in my 100-Series I was a bit concerned to see drips on the tarmac under the ‘95’. It looked as though I was going to be replacing two tanks now.
Investigation showed that the Spill Return pipe had rusted through above the tank and had been leaking over the tank and rear axle. The feed pipe looked almost as bad but being a suction pipe didn’t have any internal pressure.
I had replaced the tank guard four years ago and it was in good shape. It was, however, in the way so I removed it. This allowed me to have a good look at the tank which still had paint in places and seemed to be OK.
All I needed to do then was replace the pipes .
There are three pipes at the top front of the tank. The Diesel Feed and Spill Return we know about. The third is from a one-way valve in the tank that vents into a filter-like unit that’s held in a black plastic housing. It can be seen in the picture. The pipe looked OK so I left it alone, it’s the one on the left.
The diesel pipes take a tortuous path to the front. Once under the front passenger seat where they are protected they are OK, so I decided to cut them there. They are the upper pair in the picture . . . . Don’t go cutting the Brake Pipes by mistake
! The pipes are held in plastic clips that are bolted to the body. Spray oil and patience got the 10mm nuts free eventually. They are on captive 6mm studs that I didn’t want to shear off. Fortunately, none did.
Having undone the rubber hoses at the tank and cut the pipes near the front, I removed them and decided on what to do next. They are a three-dimensional shape which is not very easy to copy. I measured the diameter and found that the rusty steel feed pipe matched 10mm copper heating pipe. The spill return was close to 8mm microbore copper pipe but was actually a bit smaller diameter at 6.5mm OD.
I had both types of pipe in my plumbing stock so that is what I used.
The 8mm bent quite easily without kinking when using my small pipe benders – the sort used for brake pipes that fortunately accommodated larger diameters as well.
The 10mm was more difficult and kinked badly whenever I tried to bend it with the bending tool. I thought that I needed a larger former in the tool so cut the cage out of an old bearing and extracted the inner track. It fitted the 10mm pipe so I turned up an adaptor and fitted it to the tool . . . No luck, the pipe still kinked.
Eventually I had to use the tried & tested method of bending by hand around both thumbs (with gloves on) by stroking it and slowly forming the bend it went without kinking. Tight bends were not easy though. Heating the copper pipe didn’thelp. If you know Uri Geller – get him to help (yes, I know he’s dead
).I found the best way to replicate the original shape was to cable-tie the new pipe to the old as the bending progressed. Finally I had two complicated shapes on the ground.
Fitting the new pipes was relatively easy once they had been threaded up and over the rear cross members. I used the original rubber pipes and had no difficulty getting the 8mm pipe into the spill return rubber pipe. New clips were used of course.
Naturally there is a plastic clip above the N/S shock mount, in amongst the axle and difflock breathers and the wiring loom. There is no room for a socket so care, a dexterous hand and a 10mm spanner got the nut on after a bit of a fiddle. Designers should be made to work on their cars
.Further down – under the rear passenger seat – access was easy.
I didn’t get the bends quite right but they are not a bad fit. Being copper it’s easy to adjust them by hand – unless you need to lose a bit of length as here.
I joined the new pipes to the old with rubber fuel pipe and stainless clips. I put two clips on the spill return because of the difference in diameter. It has worked fine so far.
I used stainless 10mm flange nuts with ‘Optimol TA’ anti-seize paste on all theplastic clips. I hope I don’t have to undo them again but if I do it shouldn’t be a problem.
Of course, once you start looking you always find more jobs . . . .
Now I need to replace the rear output seal on the Transfer Box .
It was one of the easier jobs and not too frightening to tackle. The truck passed its MOT and I have had no more fuel leaks since doing this.
I hope it helps someone .
Bob.
