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 .Also removed filter housing and piping to check for cracks 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.
New Holland T4.75 power star hydraulic problem
oldnslo
Super Member
Where are you measuring the flow when drops from 5.5 to 3.5 GPM? In pressure line between pump and valve or somewhere else in the system?
oldnslo
Super Member
Can you move the flow meter to the valve inlet and repeat the test? If flow still drops need to move flow meter even farther upstream until flow no longer drops. That will help point towards the component that is leaking flow. Per specs I see online this has fixed displacement pump so flow is going somewhere, just need to figure out where.
5030
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I have to ask, what kind and brand of oil you are using in the gearbox sump? The gearbox and the pump share the same oil? Hopefully, it's not the low buck TSC crap or is it?
the pump also feeds the remote valves that are open center I think
No it is new holland oil
I don’t notice it as much when I am lifting a bail of hay. With no load on it at higher rpm it still jerks and the hotter it gets the more it will jerk
LouNY
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Is it only on the loader lift?
What about the loader curl or when using the rear remotes?
If it is only the loader lift and it gets better with more load,
I'd lean towards a seal sticking in the cylinder bore from heat swell.
What about the loader curl or when using the rear remotes?
If it is only the loader lift and it gets better with more load,
I'd lean towards a seal sticking in the cylinder bore from heat swell.
I replaced the seals on the pistons but not the gland seal and it still jerked I can replace the gland seal I have them in the kits. Do you think the gland seals will make it jerk so bad . The curl works fine