Need Help Priming Hydraulic Pump

[BigFatJoby]

I have a New Holland TC45D that recently decided to blow the hydraulic pump shaft seal and leak 4 gallons of hydraulic oil into my engine. I bought a pump rebuild kit, swapped out the parts, reinstalled the pump, topped off the hydraulics and drained off the extra hydraulic oil in the engine. My problem is that now I don't have any hydraulics. The pump does not have a bleed screw. The hydrostatic drive and my power steering both work (different pumps?) but my 3PH and FEL are both dead at the moment. I ran the engine for a minute and tried to cycle the controls but I was afraid to run the pump dry for any longer than I had. I backed the tractor out of my garage and up a slight hill hoping that the new oil will drain downhill into the pump and i'll have a primed pump in the morning. Other than what I have already done, does anyone have any suggestions? Thanks in advance!

 

[TedLaRue]

BigFatJoby,

I had my hydraulic pump apart, and I didn't have to prime it afterward (but my tractor is different from yours).

I think you'd have to park on a pretty steep hill to get fluid to run from the hydraulic oil sump to your pump! The pump is designed to suck the oil out of the sump, and when you park it over night, I'm pretty sure fluid doesn't remain in that intake line. It probably does remain in the pump, though.

I assume you coated the pump gears with hydraulic fluid as you were reassembling it?

Do any lines attach to the top of the pump (or maybe even the side of the pump)? If so, could you disconnect the line and pour a little fluid into that port?

 

[3RRL]

One thing that I have done and it works very good, is to pressurize the hydraulic tank from the fill or vent. I use and air hose and carefully add some slight pressure to the reservoir... not too much though. I used a rubber tipped air gun that sealed off against the fill tube, while the engine was running. Then had my wife work the fel controls a couple time and she caught on.
One thing, after you do that, take the rubber tip out of the reservoir very slowly or you will get a shower of hydraulic fluid!
Don't ask how I know that.

I used an adapter on my fill/vent.

 

[BigFatJoby]

3RRL- "One thing that I have done and it works very good, is to pressurize the hydraulic tank from the fill or vent." I actually read something along those lines last night as I was trying to get everything back together and running. I tried that but no luck.

TedLaRue- My sump actually appears to be fairly high in relationship to my pump. Maybe not as high as I was hoping though because I still had no hydraulics this morning. I do have the return line on the top of the pump so this afternoon when I get home from work I'll disconnect those two bolts holding it on and slowly add some hydraulic oil with the engine running at idle. Hopefully I'll be able to catch the overflow and shut the engine off before I lose too much fluid once it catches it's prime.

 

[TedLaRue]

I do have the return line on the top of the pump so this afternoon when I get home from work I'll disconnect those two bolts holding it on and slowly add some hydraulic oil with the engine running at idle.

Are you sure that's a return line? I would expect the pump to have a suction line input and a pressure line output. The pressure line goes to control valves which have a return line to the sump.

If that line goes to your hydraulic oil filter, or if it has a larger diameter than the other lines, it's probably the suction input line, which would be an ideal place to prime the pump.

I'd recommend removing that line, pouring some fluid into the pump there, and then replacing the line before starting the engine.