Replacing injection pump throttle shaft bushings/seals ?

[john8662]

Well, I'm driving my 82 short pickup because it's a backup vehicle. Upon doing the maintenance long overdue by the prev owner I have been discovering things.

One thing, while I had the air cleaner off I noticed diesel fuel on the valley. I'm thinking, great, now I get to R&R the pump due to leaking seals. Yep, sure enough, the leak is at the throttle shaft.

So, thats why it's a real bear to start first thing in the morning...

So I call around the two local diesel shops, both shops want half of the cost of a rebuild just to do the service.

But, the parts cost 5-10 bucks.

So, has anyone done this procedure. I don't mind pulling the pump. Or, am I better off letting someone else mess with it, if so, I've got other pumps to "try" and see if they're any good.

I'm on the cheap cheap right now...

[dieseldummy]

This sounds like what I've just discovered with my "spare" 6.2 pump I put into commission... I tore down a junk pump once and put it back together. It wasn't very hard. If you can get parts I would recomend giving it a try. That's my plan at least. That -4911 you've got is a good one, just keep off the go peddle to control the smoke. :eek:

If you've got a place that will sell the parts let me know. Nobody in my neck of the woods will even talk about selling just parts...

Justin

[BobND]

2 generic 30 cent "O" rings will fix the throttle shaft leak, if you can't readily get the genuine Stanadyne parts.

The exception to that is if the throttle shaft bushings are worn really bad. Then, new bushings need to be installed, and finished to size with a special reamer. It's rare, though, if "O" ring replacement won't stop the leaks for a LONG time.

The "O" rings can be replaced with the pump in place by removing the top cover, and undoing and removing the throttle shaft. With any luck, you can get by with re-using the top cover's square cut "O" ring gasket.

Be sure to note how the governor parts go together!

Also, the advance cam on the LH end of the throttle shaft needs to get put back exactly as it was. Taking a reading with an angle gauge before teardown will allow you to get it back where it was. The cam also limits throttle shaft endplay, IIRC around .005" to .010", you can measure what you have before disassembly with a feeler gauge, and put it back where it was.

When putting the top cover back on, you are supposed to use a special tool (wire clip) to hold the fuel shutdown lever in position while installing the cover. If the lever is in the wrong position, it could jam the governor wide open, and prevent shutdown!

Simply connecting power to the shutdown solenoid (and putting a ground jumper to the other terminal that is normally grounded by one of the cover screws) will pull in the shutdown solenoid, and move the lever to the best position for cover installation.

I have a "Motors Truck Repair Manual" 1979-1985 that details the procedure, including fastener torques. Got a library nearby that might still have one of those?

(I have a Stanadyne dealer who's more than happy to sell the pump seal kits over the counter {under $30.00 each for the last handfull I bought}, and often there are people selling them on ebay.)

[john8662]

Justin,

You've got mail!

BobND,

Thanks for the writeup! I'll need to see if my pump has any slack in the bushings. Another pump I took apart to just play with didn't have any slack at all, but I remember removing the pump for the leaking shaft problem.

I'll bet you're right in that the o-ring just needs replacing, especially if there isn't any detectable play in the shaft. I wouldn't want to have to ream the new bushings for the clearance of the shaft, which I don't know what that clearance would be.