I recently bought a '99 Jeep Cherokee XL diesel at a good price from a friend. I know the car has been regularly serviced, never been off road and had no issues.
As fate would have it the injector pump started leaking badly a week after purchase. A visit to the diesel specialists made me nearly fall over backwards. $1800 - $3600 depending on what needs to be done to the pump. When I suggested I will do it myself I was given dire warnings about the complexity of the pump and all the specialised equipment necessary to remove and replace the pump, let alone pull it apart and re-calibrate.
I like the car and it's in good nick so I want to keep it but I don't want to double my purchase price with one repair.
I did a lot of research on the net including this list. It seams that leaking seals is a common problem with these and most other older injection pumps so there is quite a bit of info out there though very little on the Jeep. This lead me to find out what other cars have our pump fitted and as luck would have it the common VW Jetta does. They have a big following so there's plenty of info including an excellent 7 part Youtube video showing how to replace the seals in situ.
and another at:
There is even one showing a guy using biodiesel to swell the seals though I thought this looks like a temporary fix only.
I bought a seal kit from an injector specialist for $16.50 which comes with a lot of seals though I only used the two large ones. I didn't replace the large round 'o' ring as shown in the 7 part video but I've got it if it starts leaking.
The biggest problem I could see with this job was that I didn't have access to any electronic wizardry to set the fuel volume as they do in the videos. The lower plate slides back and forth setting fuel volume and is extremely critical. Pros use a very expensive bench mounted calibrator to set this but that requires the pump to be removed (and $1800 - $3600). I've heard of people doing it by trial and error by tapping the slide back until the black smoke stopped bellowing from the exhaust but this sounded a bit crude. My solution was a tin of builders bog. I figured if the sliding plate went back in exactly the same place then all would be good, and it worked. Before pulling the top off the pump I cleaned it thoroughly with brake cleaner then applied some wax (car wax will do) to the front edge of the slide plate to create a release from the builders bog. I then applied the bog to the front of the pump (see photo). The idea is to create a stop so that the sliding plate can be bolted down in exact position it was before. I found it necessary to nip the bolts gently then use a large screwdriver to firmly lever the plate forward against the bog while I tightened the bolts. Don't use too much force or you will break the bog. BTW, when you have finished the job it won't be too hard to chip away the bog. I've left mine in case I spring leaks in any other seal and need to remove the slide plate again.
Another little problem is that pesky tamperproof bolt holding the plate and cover down. Evidently you can buy the correct socket but I found a 7mm socket hammered over the head works a treat. It's up to you if you want to replace it with a new bolt.
So I'm feeling pretty chuffed about repairing a very expensive leak for under $20 and 1 hour of my time.
Cheers,
Mark
How to fix an injector pump leak for under $20
2001 Jeep XJ TURBO DIESEL
