Allis Chalmers WD45 Hydraulic Oil Pump

Starmetal47 · Mar 27, 2020

Guys I posted a question on this year or more ago that the pump isn't pumping. I got a reply about pulling the pump and something about each little individual piston being stuck or something. Well finally got it off and part and nothing is stuck or rust or missing parts. The ball seals look good to. If anything one of the rollers on one piston that rides on the cam lobe is pitted some, not bad. Other then that nothing. I'm now I'm really stuck. What's my problem? Next question is can I run the tractor with the pump off and not block the hole with a plate? All the oil that was in it drains out. Please help. I have the pump soaking in gasoline now and going to clean it up and wait for y'all replies. Thanks

DrAllis · Mar 28, 2020

There are about 40 parts inside that pump. You haven't removed the four or five control plungers?? or their sleeves ?? are they pointed the right direction ?? There are four Orings on the ends of two sleeves. There are internal linkages inside the rear of the pump that could have an issue like a pin missing, etc. The unloader valve ball and its seat may be shot. In short, there is a lot more to that pump that the pumping pistons and rollers and four check balls/springs. When they are right....they work. There are four adjustment screws to configure the pump to work a certain way. When someone else has been in there and done it wrong, you have inherited a crap sandwich. Yes, a cover can be made to eliminate the hyd pump.

Starmetal47 · Mar 28, 2020

DrAllis....So far all I've done is removed those balls to see if they were stuck. They were fine and undamaged. I put them back. All the pump pistons are fine and go up and down smoothly. I did remove the adjuster screw sleeve and all it's parts and they looked fine too. I removed the cam follower with the bad roller and am going to make a new one on my lathe. I did just hit the starter yesterday while looking at the cam and it does spin and faster then I hand thought. So that eliminated that. The pump was working fine and letting it set one season it just wasn't working anymore. All the linkage was fine. That control linkage assembly at the rear of the pump,does it get lubed with the hydraulic oil or take it's own separate different type oil? I'm about to buy a used pump ebay because I'm getting fed up with it. Thanks for replying.

Joe

DrAllis · Mar 29, 2020

There is indeed internal linkage that could have an issue and it is lubed from the hydraulic oil. Those pumps are so very reliable but are victims of years of neglect from no one ever changing the oil. There is no filter of any kind on the system and dirt is the worst enemy. I've watched my Dad plug in a hydraulic hose and never wipe off the end before doing so. Any dirt on that hose end immediately goes inside the pump and then sump. Good luck with a used pump. It might be just like what you have.

Starmetal47 · Mar 29, 2020

Okay what I've found so far is on the valve assembly, the one controlled by the adjusting screw, the two O rings on the one valve were hard and brittle, and that wavy washer near the end toward the adjusting screw was missing. Working on rectifying that now.

RalphWD45 · Mar 30, 2020

If I was in your shoes, I would box up my pump, and send it to Sandy Lake imp. I think you will be time, and money ahead, to use them. I have with the B allis pump.

Allis Chalmers WD45 Hydraulic Oil Pump

Starmetal47

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DrAllis

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Starmetal47

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DrAllis

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Starmetal47

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RalphWD45

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