(quoted from post at 22:52:50 08/19/17)
(quoted from post at 10:47:02 08/18/17)
(quoted from post at 11:13:44 08/18/17)
(quoted from post at 13:33:09 08/17/17) A small/slow drip at either of those two places (control valve shaft or hole behind unloader valve) may not be of concern, as there are no seals on either, just close fit metal spool to bore.
Should oil always be flowing from the back pressure valve no matter what position the lift is?
ertainly not a "flow", but maybe a drip. Flow in hold, lower, but no flow in lift.
Ok, I put a gauge in the pump outlet. When lifting a bush hog the pressure went to about 1200 psi. Right at the end of lifting it read about 1400 psi then went back to 1200 and stayed there while the lift was in the raises position.
When lowering the lift the pressure dropped to 0 psi until it reached a preset point then it increased to about 800 psi to hold the weight at that position.
At the lowered position of course it went to 0.
Is this normal except for the pressure reading should be higher?
I am trying to figure out how the hydraulics operate (oil flow/valves) during each phase of lowering and raising.
When the tractor is first started with the lift in the lowered position the pump is sending oil through what valves? I have read the pressure is about 45 psi in the back pressure valve. Should this pressure stay at this when the tractor is shut off and remain until it is restarted to keep the pump primed or does the pump have to pull the oil from the sump to prime itself again. Seems to me if the latter is the case then there will be air in the suction line from oil draining back to thr sump.
I probably have this wrong. Can someone tell or direct me to a where I can find out how and where the oil flow at each cycle of the lifting, hold and lowering of the lift?
Thanks
Cgun