Hey all,

A couple of weeks ago, my truck decided to spring a leak at the governor shaft of the injection pump. Now that I have some free time, it is time to go ahead and pull the pump in order to fix that leak. I have been doing as much research as possible, and have watched the pump removal videos from Chrysler countless times. Additionally, I bit the bullet and bought the necessary tools to make the job a little easier - specifically the wrench used to remove the lower pump mounting nut. Having said that, I have a few clarifying questions before I remove the pump, as messing with the injection pump makes me a little more nervous than messing with most other things on my truck (1990 W250, non/ic, bone stock).

1. In order to lock the pump timing before removal, I simply back out the 10mm nut near the front of the pump, remove the special washer, and re-tighten the nut. This will ensure no change in timing once the pump is pulled, other than re-aligning the factory timing notches when re-installing the pump. Is this correct? In regards to timing, is it necessary for me to take the truck to an injection shop to verify timing afterwards? I do not have a dial indicator.

2. What is the best way to avoid dropping the drive key into the timing cover? Having just capped my KDP a month or two ago, I really don't want to pull the cover again if I can help it.

3. Do I need to find TDC before removing the pump (using the TDC lock pin), or does it matter?

My biggest concern overall is messing up the timing. I feel pretty confident in my abilities, and have done substantial amounts of reading in regards to the injection pump and its components. I appreciate all of the guidance, and look forward to your responses. Thank you all in advance!

 

You should not have to have the motor at TDC or have it timed afterwards.
The timing gear will stay engaged to the cam gear and with the key the pump can't be reinstalled out of rotation. Do not turn the motor thought as you need it to be in the same spot for pump reinstallation of thr key way. With the pump reinstalled and the mark on the side of the pump where it was when removed timing hasn't changed.

Yes pull out the special washer and tighten the 10mil bolt and the pump will not move.

I've got no experience (yet) with removing the pump with the cover on but have read of stuffing big rags in the openings so if anything did fall it wouldn't fall inside.

Hopefully others will chime in.

I'm looking at pulling my pump again possibly as either it's gear shaft seal blew or my fuel pump diphram blew, either way there is like 8 gallons of diesel/oil mix in the crankcase.

 

Few things I would do. Index where the pump is on the rear timing cover. Typically there is a line that matches another line and sets the timing on the pump. You can rotate the pump which will advanced the timing or retard the timing. A paint marker and drawing a single line will make a great reference for when you need to put the pump back in.

Lock the nut so that the timing on the pump doesn't advance or retard. The nut keeps the shaft from rotating on the pump. Go to a hardware store and get a PVC pipe that will fit the hole. I think it's a 2 1/2" or a 3" pipe.. one of them will fit snug in the hole so if the bolt does fall out it'll be caught by the pipe. Of course you'll have to cut the pipe the fit and what not. Stuff rags around it for extra safety but the pipe trick works fine. Sometimes it's good to keep it in TDC so if the woodruff key is loose it doesn't fall down in the gears. TDC should have the key at 12 o’clock. Either way the pipe will catch it if it was loose with.

Make sure the tranny is in neutral, we had a truck roll forward in gear just a hair and it was off timing by a tooth on the gear. Timing is so easy to do on these trucks, you literally connect the lines. Just a time consuming process to tear it all down.

That's pretty much it... take your time and go slow.

If for any reason you think you messed up the pump.. or you were messing with the rollers and shaft springs/distributor shaft then don't put the pump back into the truck and crank it.

Put the pump on the bench with the nut on and crank it by hand slow. I've only seen it done once and the guy at work put the pump in without testing it first and that was that.

 

I pulled mine off and put it back on without worrying about where TDC was, or locking the pump in position. Once the gear is pulled off through the front, I don't think it's an issue with dropping the key then...it's when you put it back on that it can get a little cockeyed. I had to bar my engine slightly to get the keyway aligned again...something about the pump shaft turning or the beveled gears that drive the pump sliding around...but I had a little worry getting it lined up and seated again properly...it was just a hair off, and that's enough.

Use a mirror to look down into the front to see if the key is lined up with the keyway. Pay attention to the number of threads exposed on the nut before you remove the pump...it should look the same way when you put it back on and begin to tighten it...if there's less, then you got something wrong, and the key is being crushed.

I put some grease on the key and that held it to the shaft. The key has a few divits in it to keep it stuck to the shaft too. It wasn't the hard part. I also had my PS pump out, because that was needed to get to the lower bolts on the IP...and I suspect that if the key dropped into the front cover, I could see it there. Not sure. I quite literally had it in and out about 6-8 times trying to find the slot for the key in the gear...at some point I stopped worrying about dropping the key.

Stuff a rag in the front cover hole if you're worried about dropping the nut into the front cover area.

The timing marks on mine weren't clear, so I adjusted it some so it sounded "like it did before."

For whatever reason someone had hammered on the far side of the pump at some point and that loosened some screws, which let a cover leak out a o-ring seal...and that's why I had the silly thing off. I also changed the front seal...which after taking a hammer and screwdriver to it to crush the seal so I could remove it, surprised me that it worked still. But, things turned out OK, and I just went at it slow, and kept trying.