After replacing hydraulic pump seal & o-rings hitch not raising correctly - JD 850

[winston1]

Re: After replacing hydraulic pump seal & o-rings hitch not raising correctly - JD 85

If you have no loader, no other hydraulic except 3 point I would see no reason you should have any flow restrictions. If you had flow restrictions you should hear a relief valve going off or notice tractor engine loading up.

 

[oldnslo]

Re: After replacing hydraulic pump seal & o-rings hitch not raising correctly - JD 85

Pump getting hot quick would indicate that it is either leaking severely internally or mechanically binding. Since this model has the side loading plugs you have to make sure they are installed in the correct positions. They should allow high pressure oil to get behind them and push these plugs against the gears. Installed incorrectly they could be letting the high pressure oil go back to the inlet.

Also check and confirm that the gear teeth have not enlarged the gear case allowing oil to slip past the ends of the gear teeth.

 

[dfkrug]

Re: After replacing hydraulic pump seal & o-rings hitch not raising correctly - JD 85

the only thing I find strange is that once I put that back plate on that presses
against 4 new o-rings it gets a heck of a lot harder to spin by hand. .

I have never had a good pump that was easy to spin by hand, so this is good.

You need to get a pressure gauge on the system to see what you are getting when it
fails to lift.

New seals will not fix internal pump leaks past scratches in the gears and score marks
in the body of the pump. I lean toward this being the problem, as OLDnSLOW notes.

 

[Smedium C]

Re: After replacing hydraulic pump seal & o-rings hitch not raising correctly - JD 85

Well I thought I had it fixed but seems not. It was lifting fine for a bit then stopped going all the way up. Felt the pump and it was pretty hot. Unsure what to think at this point.

When I had it apart last night the sides of the housing didn't look like they had been worn out. Maybe a scratch here and there but not bored out.

I did submerge it in hydraulic oil today and and spun it with a drill. It looked fine, pulling in from one side and pushing out the other from low rpms to high. Didn't see any bubbles or anything that would indicate that oil was being forced back out the inlet.

Dfkrug thank you for clarifying it should be tough to turn. Had me a bit worried because the difference is night and day after changing the seals.

I guess I'll start looking for a gauge.

 

[dfkrug]

Re: After replacing hydraulic pump seal & o-rings hitch not raising correctly - JD 85

Maybe a scratch here and there but not bored out.

Also look at the tips of the 2 gears. Some housings are steel, and some are Al. You

really don't want any significant scratches in there. Post a photo if you can.

 

[Smedium C]

Re: After replacing hydraulic pump seal & o-rings hitch not raising correctly - JD 85

Wow, so after pulling and tearing the hydraulic pump apart again it's a lot worse than I remember it being.

At this point I'm assuming the pump is done. That's what was causing the bypass and allowing oil to return to the inlet?

So, to avoid future repeats of this, was this something I did along the way to cause the boring out of the housing? The new seals were too much for the old pump, reassembled incorrectly, etc? Very costly mistake on my part if it was.

Also, how do the gears look? If y'all wouldn't mind, could you point out what I should be looking for on the gears so I'll know next time? They do look worn on the edges. Other than that I'm not sure what I'm looking for.

Thanks again for the help.

 

[winston1]

Re: After replacing hydraulic pump seal & o-rings hitch not raising correctly - JD 85

Pictures can be deceiving but what I think I see is worn housing, worn gears. When all this happened I have no idea. Are you thinking all the wear took place after you installed the new seals? I think a new pump is your answer at this point.

 

[Smedium C]

Re: After replacing hydraulic pump seal & o-rings hitch not raising correctly - JD 85

Yeah, that's what it seems like. Before I replaced the seals it was functioning but leaking quite a bit. When I first took it apart I ran my fingers through it and it felt smooth with just a couple knicks. Now it's very scratched and there's definitely a groove/indentation where the gears would be. I'm not sure how this all would happen from changing out seals/rings is why I ask. Looks like I'll be speaking with Hoye in the morning.

 

[winston1]

Re: After replacing hydraulic pump seal & o-rings hitch not raising correctly - JD 85

Almost looks like in ran dry.

 

[normde2001]

Re: After replacing hydraulic pump seal & o-rings hitch not raising correctly - JD 85

Almost looks like in ran dry.

My thoughts exactly. Was it primed, (filled with oil) before installing?