New Holland T4.75 power star hydraulic problem

[Ncjim919]

The loader jerks really Bad when the oil is hot . I have replaced the pump, loader control valve, relief valve, change filter and oil ,replaced all suction hoses on suction side of pump ,changed the quick couplings and switched the hoses on the lift and replaced the cylinder packing . Installed a flow meter on the lift hose, I have 5.5 gallon a minute at idle and it will drop to around 3.5 when it jerks and go back to 5,5 till it jerks again and pressure stays around 500 when lifting . Pump puts about 11 gallon at 1500 rpm’s . When the oil is cold it does not jerk the warmer it gets the worst the jerking. I have talked to the dealers around here they were no help. Any recommendations you have will be very helpful.

 

[used red MN]

Hello Jim, welcome to YT! Well as you can see not much response here. I would recommend you post this on New AgTalk Machinery Talk
The majority of poster there are active farmers. This tractor may be in the “smallish” range for most modern farms but there is a chance someone there knows something about your problem. Good luck!

 

[rustred]

what pump do these tractors use? and is there a charge pump on the pump? there should be an adjustment for that.

 

[Ncjim919]

It is a gear type pump does not have a charge pump .The pump is mounted on the side of the motor the discharge line goes to the loader mid mount valve and a separate lines feeds the remotes and 3 point hitch .

 

[E.B. Haymakin']

It is a gear type pump does not have a charge pump .The pump is mounted on the side of the motor the discharge line goes to the loader mid mount valve and a separate lines feeds the remotes and 3 point hitch .

I wonder if there's a connection somewhere thats not totally tight and sealed which allows it to suck air into the hydraulic system. I replaced two hoses on my 3010s with woods 1020, one was visibly leaking at the jic male and female coupler on the metal line though. But the jic male was on a swivel that was swagged into the hose, and could have leaked there. Either way new hose and sealer on I have no stutter in bucket curl and no frothing of hydraulic oil

 

[E.B. Haymakin']

It is a gear type pump does not have a charge pump .The pump is mounted on the side of the motor the discharge line goes to the loader mid mount valve and a separate lines feeds the remotes and 3 point hitch .

And make sure it is topped up. When my gear drive 3010s was frothing it made reading the dip stick hard. I got to where I some everyday to be safe

 

[Ncjim919]

I have replaced all the hoses also the new holland dealer said the filter base was probably cracker so I replaced it . I removed the loader and baled hay and you it still does it when I open the door on the bailer. I don’t have any bubbles in the oil that I can see when I check the oil . I put a clear tube on the vent and put a little oil in it to see if the pressures was building up in from any air that was getting in the system . Did not see any build up in pressure . Talk to another new holland mechanic and he said he was at a loose of what was wrong with it . I don’t have any leaked on the steel pipe flanges going to the pump or the rubber hose connection .

 

[mtf]

What about the oil cooler, is it clean and does it have airflow? What is temperature coming in and coming out of cooler? Sounds like oil is getting too hot!!

 

[Ncjim919]

i cleaned the oil cool and washed it out the oil don’t seam to be getting hot the steering and 3 point hitch works fine .I put a flow rate gauge on the loader lift you can see the rate drop when the oil is not just warm . When it drops it will come right back with flow and pressure

 

[E.B. Haymakin']

i cleaned the oil cool and washed it out the oil don’t seam to be getting hot the steering and 3 point hitch works fine .I put a flow rate gauge on the loader lift you can see the rate drop when the oil is not just warm . When it drops it will come right back with flow and pressure

Discussed on these forums many times has been closed center hydraulic systems and open center hydraulics I believe, manufacturers very between model on which system is used. I do not fully comprehend the differences but I do get if return flows aren't returned to the correct locations serious problems result. Next you engage the dealer...I would ask was my loader set up correctly...whether they did mount it or not I would try to eliminate that as an issue.

 

[E.B. Haymakin']

i cleaned the oil cool and washed it out the oil don’t seam to be getting hot the steering and 3 point hitch works fine .I put a flow rate gauge on the loader lift you can see the rate drop when the oil is not just warm . When it drops it will come right back with flow and pressure

According to tractordata the T4.75 that was manufactured between 2012&2014 lists a "fixed displacement" hydraulic system. The T4.75 manufactured till 2017 lists "closed center" as does the Power star 75 manufactured since ,2018. What if it was set up for the wrong system? How old is the unit. Check tractor data and call CNH technical and see if whoever set it all up has it right, whether it was the dealer or whoever, maybe the installers consulted the wrong manuals.

 

[Ncjim919]

My tractor was built in June 2014 it worked perfectly until last summer when I finished cutting hay. Thats when we replaced the pump, relief valve , midmount hydraulic control valve ,rebuilt the lift cylinders, checked hyd coupling and hoses , replaced hyd filter and base , all new suction hoses to the pump and replaced the suction pipe o-rings inspected the flange connection , checked the return line to tractor rear case .

 

[E.B. Haymakin']

My tractor was built in June 2014 it worked perfectly until last summer when I finished cutting hay. Thats when we replaced the pump, relief valve , midmount hydraulic control valve ,rebuilt the lift cylinders, checked hyd coupling and hoses , replaced hyd filter and base , all new suction hoses to the pump and replaced the suction pipe o-rings inspected the flange connection , checked the return line to tractor rear case .

It sounds like you have covered everything, I would imagine with such an extensive rebuild the correct hydraulic fluid was used. Best luck to u

 

[Ncjim919]

I did use new holland oil . Thanks very much. If you think of something else please let me know

 

[Trueheartx01]

I have a powerstar 75 1 1/2 year old loader doing the same, If anyone gets an answer please post. I added a quart although the stick shows full, just to try something. I plan a trip to the dealer before the warranty runs out ato let them check that and whatever may be wrong. If I find an answer, will post.

 

[Ncjim919]

still working on it I have removed the valve on top of the 3 point hitch that is under the seat and replaced all the o-rings ( they are some kind of expensive to) still doing the same thing . I noticed it does it also when I open the round bailer door it is hard to notice it because the cylinder is so small . If you find out what is wrong

please let me know any help is appreciated

 

[Trueheartx01]

Will do, going to take it in to dealer as soon as my trailer to haul arrives, due mid Sept.

 

[Ncjim919]

Ok thank you