Repairing my Hd7g pump.

Well, as it is my policy to share anything I learn about these things with everybody, with no commercial angle involved, I'll show some steps I'm taking dealing with my problem of no start/ overspeed, stalling on my tractor. I've determined that the control sleeve in the injector head is binding on the injector plunger, causing the plunger to not return to it's inactivated position, thus, short-stroking the injector stroke and causing the no-start. A good indication that this sleeve is binding/sticking is, when cranking the engine over, the bellcrank on the control sleeve shaft will cycle wildly. It is being dragged up and down with the plunger as the cam operates it(the plunger). You might get by with cleaning this area through the control sleeve actuator port. This problem began 6 months ago when I started the engine, it ran up to wide open throttle. I pulled the shut-off handle and it died. I took a considerable amount of coaxing to get it ot restart, it then running fine after that. The next time I started it, same thing but considerably more trouble getting it to restart. Last weekend It took me hours to get it to start, but once it did, it ran fine and I worked it for 2 hours and it ran perfectly. Anyway, the problem is that the control sleeve is gummed up. I pulled the head off the injector pump today and I can see clearly a dull appearance on the plunger shaft indicating slight galling. The clearances between these parts is so critical that no they must be mirror smooth. I'll disassemble this assembly and polish/lap the offending parts and I should be back in service. Now, getting all the injector lines off of this old gal was much more difficult than pulling the injector head. Also, these 50 year old fittings on the injectors are full of old diesel gum and rust, and they leave debris on the injector ports after they're removed. I'll suck that crap out of there and hopefully they have their screens . While I'm doing this, I'm removing my fuel tank and steamcleaning the inside and then acetone treatment. The return line system from the injectors has some sort of rubber 0ring or seal, I'll have to find a source for them. Almost 50 years old I figure she deserves some love. All in all a heckofa day and 5 hours of pole barn roofing I'm beat. 

Thanks again, Ian. Yes I believe the grommets can be made out of the right-sized hose. As bad as the old ones looked, it's surprising they never leaked. The little bridge piece that retains the control shaft was cracked into three pieces, cracked right where the screw bosses meet the "bridge' part of the piece. I'll have to fabricate a new one from steel spacers and a tiny piece of tempered aluminum. Had I known that I could access the trouble area through this port, I possibly could have avoided removing the injector head. The control sleeve area is in kind of a no-mans-land insofar as lubrication is concerned, and it's not surprising that this area is susceptible to airborne corrosion elements. At any rate, now I know exactly what's in there and how to recognize the symptoms of this problem. I've been building my pole barn for what seems like forever so I'll have a place to keep my three old tractors out of the weather. That would stop a lot of condensation and rodent-damage to my machines. Cheers.

doctorcorey

The heads on the PSB's on our grader have an oil feed via a stud with a square section o-ring (which I gather is unobtanium).  I'm not sure what gets oil.  And seems some did away with that feed by a list of head numbers and useage that I tripped over.

You might pick up that piece from a wrecked pump via an injection place?

Best of luck with it


Edited by Ian Beale - 14 Aug 2017 at 4:44pm

Yes, definitely the challenge is to get and then keep everything absolutely clean. The plunger on my pump had those shadow marks from the various cylinder ports etched into it, likely from sitting for a long time without running. Just enough corrosion to feel a slight drag with a fingernail. Enough to cause binding. It's funny, but when these parts were practically dry they would move smoothly, but add some diesel to them and it would cause drag due to the inadequate clearance being taken up. I polished the plunger and cleaned the housing to death, and now it all moves nice. Then straight into a ziploc bag. I would warn anyone polishing one of these valves to avoid touching the sharp edges of the plunger with any tool or compound. IOW, no chamfering! These sharp edges are critical to the self-cleaning  ability of this valve.  BTW Dennis, did you stay with that home made "joystick' shovel control setup from that 7g you bought? I always wondered if that can be made to work very well. Lastly, Ian, my pump has that plug in the housing at the rear base of the injector head. Some sort of port or orifice but I need to look at it more closely. That is where that exploded view of the psb pump showed a filter in that area. I believe that the control sleeve is diesel lubricated by the bleed off from the plunger port. It's just been a lot of years since I've worked on injector pumps, and with the prospect of ruining irreplaceable parts, makes one a bit nervous and over-cautious.

This might be a furphy** but I've heard that it is possible to change the PSB pumps over to American Bosch 100 series.  Any truth in that?

Mind you other comments seem to suggest that the parts situation isn't a great improvement for them either.

** Translation - http://www.urbandictionary.com/define.php?term=furphy

An early outdoor version of the watercooler rumour.


Edited by Ian Beale - 15 Aug 2017 at 6:29am

Coke-in-MN wrote: hate to burst your bubble - them buildings give the varmints a dry place to do their bad things to your good stuff.   Plan on putting bait stations around the perimeter with wax block bait. anything finer they carry off and store for later

I found that that coyote pee spray works pretty good but initially smells awful. Getting my machines out of the rain and UV light is my main concern, though our otherwise useless Dachshund is a pretty good varmint abuser.

When I removed the injector head some weeks ago (due to sticking, gummed up plunger and control sleeve), the little 'button' that rides between the cam follower and the injector head plunger remained in the follower bore. I used some 30 year old bearing grease to 'glue' the button to the plunger during re-installation and it ran fine. No retainer piece  was seen.  Now last weekend my machine wouldn't start and I determined that the plunger was not stroking. I removed the injector head once again and found a piece of the old retainer floating around in that cavity above the cam follower. I think I've been experiencing a sticking cam follower, likely caused by debris from that destroyed retainer clip buggering up the follower bore. Once I got the engine running it will run all day. I'll continue flushing that area and using some high-pressure lube administered directly through the shut-off window. Of course, there are virtually no parts available for this pump, save for buying a whole pump that probably has been stripped of the vitals. I imagine that a lot of these parts were sitting in old men's toolboxes, sold after they passed away for scrap or discarded by the auction winner. 

You might check with taylor diesel in north little rock arkansas the are a bosh dealer and have been for a LONG time i heard they still had parts for the old pumps