3-Point Hitch jumpy 3 point lift

[MAYOR8020]

i have a tc40a 1212 shuttle shift w/ loader 16la .
sometimes the 3 point lifts and some times it doesent
happens mainly when i have 6' squealer bush hog on.
i took it to dealer and they said the hyd. relief valve was sticking and needed to be shimmed they shimmed it and it worked well.
now it is starting again does anyone have any ideas as to what to do
i am thinking about taking it apart and lightly buffing valve w/ emery cloth fine grit to possibly remove a bur which could be catching
also to add when the 3 point wont lift if i rev it it will lift like @ 2000rpm
also when i lift this way it will come up 1/2 way jump then raise all way up
then it works well ????????????
david

 

[Soundguy]

It does sound like a sticky valve.

if it's under warranty I'd carry it back in and let them fix it again...

If not.. and you know what you are doing with the valving.. by al means.. disassemble and inspect.

When it does lift.. does it seem to be lifting at full strength?

when did you last service the hyd fluid and filter?

Soundguy

 

[MAYOR8020]

its out of warr. when lifting yes it is under full lift capacity but goes up about 1/2 way then stops for a second then its like the valve opens and it lifts all way up then after that the lift works fine
hyd. filter was wac changed @ 50hr and i only have 200 hr. on tractor

 

[jinman]

its out of warr. when lifting yes it is under full lift capacity but goes up about 1/2 way then stops for a second then its like the valve opens and it lifts all way up then after that the lift works fine
hyd. filter was wac changed @ 50hr and i only have 200 hr. on tractor

You only have one pressure relief valve on that hydraulic system. If the 3PH lifts erratically, then the 16LA loader should do the same thing under a full load. If it doesn't, then your problem is in the 3PH hydraulics and not the relief valve.

I'd ask your dealer to measure/monitor pressures or you could do it yourself, but it would cost about $50 to buy the gage, hose, and adapters or quick connects. If you relief valve is holding, the pressure from the pump should remain constant. If the relief valve is sticking open, you should see that very easily as an instantaneous drop in pressure that stays that way. Of course, if you have a leaking lift cylinder, it will drop pressure also at the point it leaks. So what I would do is monitor the relief pressure while operating the 16LA. When the relief lifts, it will stick open or go immediately shut when the joystick returns to neutral. If it goes immediately to shut, then your problem is internal to the 3PH hydraulics.

My point is that you need to know if the FEL has the same problem as the lift. If it does not, then your problem is not the relief valve.