Stanadyne ijection pump failure.

2x4

Well-known Member
Shop just examined mine from the JD 550G. Shaft has sheared. One ear lobe of the 3 that mount to the housing was also broken out. $1700 to repair mine or $1350 for new pump, they say. Didn't say if they knew why it failed but it had been powering out on an intermitant basis for a while, running fine sometimes, lugging down on a hard pull. Finally it would only idle but die if you tried to lift or angle the blade. Then it wouldn't run at all. Prolly no cheaper alternatives. The broken ear prolly means no core charge credit. Any money-saving ideas?
 
Best idea is to check around online. Buddy thought the other day he needed an injection pump and had priced them locally at nearly $1700. He got online and found one someone had listed selling like excess inventory, or whatever, that was brand new, for less than $400. In the end he didn't need a pump, just had to change injectors, glow plugs, etc. Regardless, a simply look online would have easily saved him around $1300 if that had been his problem.
 
A good money-saving tip would be to clean up the fuel system, and keep any fuel you store or handle CLEAN as very likely moisture and/or debris caused the pump to lock up, and you don't want THAT to happen again!
 
Sounds like retainer flex ring failed and with continued use the retiner pins sheared off, which then locks head/rotor assembly, and shaft breaks. Will be seen on teardown inspection if that's what happened.
 
There is no "flex ring" in that pump. 550G uses a DB2 or a DB4 pump that uses an EID drive instead of the plastic ring like the JDB pumps had.

The story sounds to me of one of bad fuel with low lube.
 
If you need to save money - maybe you need to find someone willing to take the pump apart and fix as needed. You need three things - at least. #1 - a new head & rotor assembly for maybe $400. #2 - a new driveshaft. #23- find out what it failed to start with.

You could work around the broken ear of one of the mounting areas. But you must find out what the pump seized up. That shaft was designed to snap in two if the pump turned too hard. The main part of pump is the "head & rotor" assembly in essence - is a rotating shaft inside a steel bushing with no bearings. Just flat metal to metal with maybe .0002" clearance and lubed only by whatever fuel you are using. Your's galled up and seized. It did so either because the fuel had poor lube (or water in it) . . or . . . a piece of metal debris got into it from somewhere else in the pump.
 
JD has it nailed, you must find out what caused the failure so it does not happen again. Stanadyne has a service letter/pictures of head seizures. With rotor pressed out of head the cause can be found. Not common, but delivery valve spring can break, with end entering port, locking the rotor.
 
Prolly not going to be able to find someone to work on it so will buy a new pump. The work around of the broken ear was done by the last owner. Since it broke thru the eye, they enlarged the partial hole somewhat & ground down a nut to act as a washer, which filled the space nicely, then bolted that ear. With the other 2 bolts holding, it was solidly mounted. But it means someone had the pump off before me, so they could have already been having some problem. It may or may not be the original pump. There was a small amount of water in the glassbox filter but in numerous bleedings, only pure diesel came out the bleed nut at the top of the filter. Had put a new transfer fuel pump on & hand pumped it up & bled it. At the bottom of the fuel tank, the water bleed screw only let out a teaspoon-full. Haven't talked to the repairman yet about the cause.
 
I can build you a pump cheaper than you have been told. Give me a call and I will see what I can do 231/757/0064 Al Baker
 

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