801 Hydraulics

[DRD in Pa]

I have an 801 series tractor that has a hiccup in the lift. I have replaced the orings in the lift cover and honed the lift cyclinder and replaced the seals with no improvement.When I look in the side cover hole with the engine running there is a squirt of oil coming out of the unloader valve above the control valve every time it hiccups.When I shut it off with a load on the lift it leaks down slowly with oil leaking out of the unloader valve.I did replace the unloader oring with the original.I have heard this a common problem with these tractors but it is annoying and I would like to repair it if not to expensive.

 

[JMOR]

(quoted from post at 15:47:30 06/01/11) I have an 801 series tractor that has a hiccup in the lift. I have replaced the orings in the lift cover and honed the lift cyclinder and replaced the seals with no improvement.When I look in the side cover hole with the engine running there is a squirt of oil coming out of the unloader valve above the control valve every time it hiccups.When I shut it off with a load on the lift it leaks down slowly with oil leaking out of the unloader valve.I did replace the unloader oring with the original.I have heard this a common problem with these tractors but it is annoying and I would like to repair it if not to expensive.

When I shut it off with a load on the lift it leaks down slowly with oil leaking out of the unloader valve". Humm.....when shut off, the components holding pressure of raised lift are ram cylinder safety valve, check valve, ram cylinder, hydraulic control valve......notice that the unloader valve is not included in this list. Since both the hydraulic control valve and the unloading valve dump out via the baffle plate, it isn't likely that you can determine the source of the oil by that observation. At any rate, the unloader valve is not involved in holding up the lift in a tractor engine off situation.