Leaking Injector Pump

[Nemos]

We have a Perkins 4108 with a Lucas CAV injector pump that is leaking from the throttle shaft. The pump only has about 1000 hours on it and removing the pump is difficult because of the heat exchanger. There are some postings on the site that say you can just change the o-ring seals on the throttle shaft, but don’t give a description of how to do that…

Any advice on this would be much appreciated.

Thanks

Norman

[Maddog]

Get it re-built. All that needs to be said.

[perchance]

I agree with Maddog. Injector pumps and injectors are best left to the guys with the proper tools , expertise and a shop.

[beetle]

I just went through this, and I went whole hog and repowered (something I was planning to do anyway, the cost of the injection pump rebuild accelerated the process).

That pump leaking where the throttle linkage exits the pump body is indicative of main shaft seal failure - not a guarantee, but a likelihood.

To confirm, you need to pull the pump from the engine: remove the heat exchanger, disconnect the copper hi-pressure lines from the pump, and extract the pump (on my engine I had to invent a very long, strong tool to reach in behind the pump to get at an allen screw, as I didn't have Perkins Special Tool PD.130A). Scribe two lines across the connection between the pump body and engine before unbolting the pump (this is handy for re-attaching the pump to the motor later on). Do NOT move the engine pistons at all if you're pulling the pump (timing problems will result).

With the pump in hand, if diesel fuel drips out past the shaft as you rotate it with your fingers, then you have a leaking main shaft seal - rebuild the pump. I was quoted, on average, $1,000 to do this from the various shops that rebuild those pumps.

- rob/beetle

[JiffyLube]

It might cheaper to buy a new injector pump than rebuild.

[shakey doug]

G,day Norman,

If the throttle shaft seals are leaking they are easy replaced. First thoroughly clean pump top area only use lint free cotton rag. Note clearance between throttle control arm and pump body for correct re assemble clearance,then remove throttle cable to one side.Inboard from throttle control arm you should find the throttle high & low speed adjusting screws, undo the next screw going inboard 1/4 AF, DO NOT UNDO SCREW & LOCK NUT ON VERY TOP OF THROTTLE BODY,now push STOP arm forward to run position,then pull throttle shaft out- if stuck also remove bolt in the same position as the one all ready removed on the stop lever side of the body, hold top of body when removing throttle shaft some shafts have 2 ''O'' rings others only have 1.Ring kits avaliable for less than $50 or go to a engineering supply shop and match sizes in a fuel compatable material such as viton. Reassembly is straight fwd ,checking STOP lever in run position and throttle lever to body clearance is correct, bleed air out of throttle body before start up.
Most times it longer to get access than to do the job depending on model we had a real run on seals a couple of years ago with reduction of sulpur in fuel.

Good Luck, Shakey.

[Nemos]

Shakey;

Thanks.

There were a number of posts on the web that indicated you could do this – but I think you are the first person to describe it in detail.

What does “1/4 AF” mean?

The logic of trying to do this before pulling the whole pump seems clear to me…if it doesn’t work we can always pull the pump.

Thanks Again.

Norman

[shakey doug]

G'day Norman,

I have described the procedure for the most common cav dpa type pump as fitted to perkins 4.108 motors. 1/4'' AF is a spanner/ socket size.

Cheers, Shakey.

[osirissail]

Originally Posted by JiffyLube

It might cheaper to buy a new injector pump than rebuild.

Not possible with Perkins. The original company went out of business years ago. Ford and Sabre purchased the name and inventory. Only rebuilt pumps are available and usually on an "exchange" basis. You turn in your pump and they give you a rebuilt from somebody else.

[downunder]

Around 10 years ago when Australia moved to low sulphur fuel most of older motors had fuel leaks related to fuel pump seals that need changing for the low sulphur diesel.

[beowulfborealis]

Did you say "Lucas"?

May God have pity on your soul...

[Nemos]

Unfortunately, pulling the throttle shaft was a no go…it turns out it is held in place by one of the screws that hold down the governor. Had to take the whole hydraulic governor off. Rebuilt it on a bench but can’t get the throttle shaft back in with governor back on the pump…

Oh well….I tried!

Next step is to pull the heat exchanger and remove the pump for a swap out….can someone fill me in on that “special tool” that is needed to get the screw behind the pump out?

Thanks

Nemos

[Dynamo1181]

I bolt is an allen head . Seems like it was a 5/16". I cut a 1' piece off my allen wrench and put one end into a 1/4" drive socket that fits the 5/16 allen piece. I use 2 10" extensions on the drive and socket to reach behind the pump to engage the bolt. Worked well for me, I just dont remember the exact allen wrench and socket size.
A

[beetle]

Originally Posted by Dynamo1181

I bolt is an allen head . Seems like it was a 5/16". I cut a 1' piece off my allen wrench and put one end into a 1/4" drive socket that fits the 5/16 allen piece. I use 2 10" extensions on the drive and socket to reach behind the pump to engage the bolt. Worked well for me, I just dont remember the exact allen wrench and socket size.
A

Yep, that's about what I did. I have an allen wrench set that fits the electric drill, connect that to an adapter from hex-drive to 1/4" square socket drive, connect that to a 4" socket extension, connect that to a 6" socket extensions, connect that to a 1/4" socket handle - slide the contraption in behind the pump and with a flashlight you can peer in behind the pump and jiggle the allen wrench into the bolt - apply force.

Was easier to do with the starer motor and exhaust manifold removed first.

- rob/beetle

[Nemos]

You had to do all of that - even with the exhaust system heat exchanger removed? Oh my gosh….!

Why did you have to take off the starter motor as well?

Before I do that, does anyone know why the accelerator shaft won’t go back in the governor? If I could just get that back in, I might not need to swap out the whole pump….

Nemos