bosch pump priming

1 Puller · Jan 2, 2010

I have a 600/900 with a Bosch 12p20112 pump. Has not run for a while. Changed fuel filters and now cannot get the pump to prime. I have fuel going in the pump & out the return & out the bleeder on the pump drive end. I now have the injection lines off and getting nowhere. Anyone have any help?
Thanks for the help.
Mike

DJM75 · Jan 2, 2010

if its the same as the one on my 830 its an inline and those plungers get stuck if you dont use them too often because it is the diesel that lubricates them. Take the window off the side and you should see them try and get them to move up and down. hope this helps.

mEl · Jan 2, 2010

Try removing the long cap on the front of the pump toward the radiator with the 3/4 flats and see if you can get the rack to move, it is probably stuck in the shutoff position. The end of the rack should stick out far enough to get hold of it and gently try to move it back and forth. Don't sledge on it but tapping it with a few little taps may help. Put the throttle in the WO position, that will put the rack movement spring loaded toward the front. It should move very freely against a little spring pressure. Let us know how it goes. mEl

1 Puller · Jan 3, 2010

Thanks for the help guys. The plungers, fuel rack, and the check valves were all stuck. Looks like it was run on green oil before. I don't know how long it had sat before I got it. It is now running and runs great.
Mike

Addies · Jun 7, 2011

Take off the positive off the 044 pump and fill the surge tank 1st with the lift pump.

bosch pump priming

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