Perkins 4.108 Injector Pump Leaking Fuel

[Mike Sibley]

I have a fuel leak from the injector pump on my Perkins 4.108. The leak appears to be at the point where the throttle control rod enters the pump housing at the top of the pump. I assume that it is a worn O ring or something similar, but don't really know. Unfortunately, the heat exchanger is located above the pump and denies easy access. Has anyone had a similar problem or know what the needed repair involves?

[Chief Engineer]

You are wasting your time if you don't pull the heat exchanger and access the side of the engine. I know it is a pain in the heinie but in the long run you will be better off.

Best to let an injection shop do the rapair.

[shakey doug]

The new low sulphur diesel has been causing problems with older pump seals here in Aussie ,the Chief is right remove heat exchanger makes life so much easier. There is a seal kit availiable for your dpa pump a service shop will have in no time at all.

[Maddog]

I had the same problem on a 4-107. Basically the same engine. I bit the bullet and replaced the whole injector pump. The improvement in performance was noticeable, no more leaks. Have your pump rebuilt and be happy.

[daedaluscan]

Its a CAV pump, the same body that I have on my Westerbeke W50

I had the same thing and ended up getting the pump rebuilt - end of problem but $900 later...

[Maddog]

Check out S&W Diesle in Willmington, CA. Rebuilt pump for $500 w/ core exchange. Ask for Bob or Armando.

[Mike Sibley]

OK, I accept that I will have to spend some serious money to get the problem fixed. I was hoping there was a simple and inexpensive solution, but it sounds like having the pump rebuilt is necessary. I guess the first step is to drain the antifreeze and remove the heat exchanger. I suspect that I can figure out how to do this. I guess the next step is to remove the injector pump. For some reason, I think that this involves several opportunities to really mess things up and make the job much more time consuming and difficult to complete. I guess I would need to first remove each of the individual high pressure lines and all the other steel fuel lines connected to the pump. Also, I suspect that there is a potential problem in getting the pump reinstalled so that the proper timing is preserved. If anyone has gone through the process, any words of wisdom or helpful suggestions would be greatly appreciated. I am not a mechanic, but am stupid enough to give anything a try.

[Chief Engineer]

Have faith my friend...there are enough of us here to walk you thru it.

Do you have a shop manual?

[Mike Sibley]

I have a 1983 Perkins Workshop Manual for 4.108, 4.107 and 4.99 Diesel Engines. However, it is not especially detailed regarding removal of the injector pump. And it seems to be written in a strange language that probably makes sense to British diesel mechanics, but not to me.

[daedaluscan]

I did this three weeks ago on my W50. Same pump basically.

Access was the real problem but it is a straightforward job.

Remove all lines (4 injector, two low pressure from the secondary filter)

Remove throttle and stop linkage

MARK the timing, best way is to scribe a line from the pump flange to the mounting plate. Mine actually had a line on the pump flange and a movable arrow plate on the motor. I simply lined these back up when I reinstalled.

Remove the three flange bolts and slide the pump backwards. The splined drive had a single King spline on mine so it could only go in one way.

Reinstall, bleed and start. I did all this at anchor in Sausalito which added a bit of stress.

I was offered the option of just fixing the dripping shaft seal which would have been way cheaper, but after all that effort and since I am off to the S Pacific I went for the full rebuild. I have a friend in the UK who has actaully done this himself on his tractor, but I would not recomend it as cleanliness is vital and the potential for error is high (Changed the shaft O ring)

[Maddog]

Originally Posted by Mike Sibley

I have a 1983 Perkins Workshop Manual for 4.108, 4.107 and 4.99 Diesel Engines. However, it is not especially detailed regarding removal of the injector pump. And it seems to be written in a strange language that probably makes sense to British diesel mechanics, but not to me.

HAH! it took me a minuet to figure out, "Slacken the Bolts". Good thing when I reinstalled the unit I "Un-Slackened" them.

[donradcliffe]

I was able to do it without removing the heat exchanger, but had to make a tool to remove the 3rd bolt behind the pump, which is actually an allen head bolt. Took a long drill extender bit with a hex on one end and ground to fit, plus some flats on the other end. Have fun!

[Maddog]

Originally Posted by donradcliffe

I was able to do it without removing the heat exchanger, but had to make a tool to remove the 3rd bolt behind the pump, which is actually an allen head bolt. Took a long drill extender bit with a hex on one end and ground to fit, plus some flats on the other end. Have fun!

Roger that. I had to do the same thing. I found long hex extentions at Harbor Freight that attached to my 3/8" drive. Still it was no fun. Why did they put that Allen on the back side? Was it just to make us suffer?

[daedaluscan]

British diesel mechanics are British and this type of language is learnt at birth. I moved to Canada 30 years ago and still confuse the hell out of people when I talk about motors and cars. Even when I am saying the same word they don't understand my accent!!!

[Chief Engineer]

ring spanners and prickers and sprayers?

Originally Posted by daedaluscan

British diesel mechanics are British and this type of language is learnt at birth. I moved to Canada 30 years ago and still confuse the hell out of people when I talk about motors and cars. Even when I am saying the same word they don't understand my accent!!!