Rebuilt Hydraulic Pump

I would make sure you have Zanes jig. Make sure everything is spot on with the settings.

I was very meticulous with cleaning the insides with keorsene and brake cleaner (on sale for .50 cents per large spray can)

fresh gaskets and make sure your mating surfaces are clean.

if you have plugged up areas in the pump maybe it is due to floaters in the fluid.

I rebuilt my pump with the naa piston and o ring. this combination is better than viagra as my lift arms have been up for the last 2 days with 1" of drop with 500# on them.....think i should drop that implement.

I put in a new exhaust valve assembly in the pump before installing it again.

Here's a story I heard on this board a while ago: Man is driving his tractor doing some work with a box blade. His son, daughter-in-law and grandsons pull into the driveway for a visit. Man shuts tractor off and goes in the house to visit.

After a few minutes of adult chit-chat, the grandsons get bored and go outside to have fun. Grandpa's tractor looks real fun so they start playing on it. One boy on the seat making engine noises, turning the wheel, fiddling with the knobs and levers. Sure enough he pushes the touch control just when his brother is under the box blade.

By the time the youngster can run in the house, get the adults attention, they run out and start the tractor back up and lift the blade, the boy is dead.

You cannot monitor that tractor with the 500# in the air 24/7 for two days. Why take the chance?

I've done it by lifting the implement then putting a piece of lumber under the drawbar a few inches down.. or by running a chain under it and up to a fixed support.. like a crane/boom pole.. engine lift.. sufficient barn support member.. etc.

That way you can measure hang time under load.. and limit the fall of the implement.

Soundguy

For simple testing.. just about any oil would have worked.. and no.. the somewhat disputed 80w90gl-5 oil did not harm your lift.
Most likely.. your relief valve is poped open.. or the control valve is not letting oil to the pump. This assumes that the pto is spining.. and you don't see any obvious problems.. like cracked housing.. etc..

Also.. removal of the lift cover is not necescary to get at the control valve.. the dipstick side cover can be used for that. Does the control valve move smoothly?

Soundguy

Soundguy