Hi.
I am helping a friend with a B7500 tractor that has had a front loader in perfect working condition.
He just bought a brand new in Kubota crate, front snowblower with hydraulic motored directional chute.
We followed the hyd hose instructions many times, hooking the new blower to the 4 existing loader valve body connections.
The blower lifts and lowers perfectly.
The hydraulic motor to rotate the snow chute only moves the chute in one direction. When trying to go the opposite way, the hoses flex like a blockage.
....And the hoses stay flexed from high pressure when you let go of the joystick
Next, we swapped the two hoses to the chute. It now will go the opposite direction, but now won't go the opposite way that it did before. So, the chute motor is OK
Next, we assumed the "old" male quick disconnect fitting on the "suspect" valve body connection was not letting fluid pass into the new female quick fitting on the new blower hose. So we eliminated both quick fittings by using two swivel unions. The chute still only goes one way.
Next we put an inline pressure gauge at both chute hoses. On the circuit that does work OK, the gauge shows 1500 as you rotate the chute, then quickly drops as you let go of the joystick. On the "bad" side, the gauge goes up to 1500 but stays at full pressure as you let go of the stick.
So we thought plugged return. We pulled that spool out of the valve body, and everything looks clean.
We then swapped all 4 of the hoses to see if the "suspect spool" could raise/lower the blower, and to see if the chute would now go both directions. The chute now works perfectly both directions, but the when you push down on the blower to lift the front tires off the ground, it stays up, and won't let that lift cylinder to retract, so the tractor gets stuck up in the air.
The crazy part: We took the blower off. We put the front loader back on. The bucket raises and lowers perfect, and the curl/rotation of the bucket works perfect.
... BUT..if we swap those 4 hoses, the curl still works perfect, but when you lift the tractor wheels off the ground by lowering the bucket, the front wheels stay off the ground when you try to raise the bucket. ??
We got out the bucket intallation manual to see if the original bucket valve body hoses were hooked to the tractor correctly when the tractor was new. Like the "pressure beyond" and "pressure", and "return", to the transmission side, and to the fluid block. They match the book.
How can the bucket attachment work perfect, but we keep getting symtoms of a blocked return line on other test hookups?
I am helping a friend with a B7500 tractor that has had a front loader in perfect working condition.
He just bought a brand new in Kubota crate, front snowblower with hydraulic motored directional chute.
We followed the hyd hose instructions many times, hooking the new blower to the 4 existing loader valve body connections.
The blower lifts and lowers perfectly.
The hydraulic motor to rotate the snow chute only moves the chute in one direction. When trying to go the opposite way, the hoses flex like a blockage.
....And the hoses stay flexed from high pressure when you let go of the joystick
Next, we swapped the two hoses to the chute. It now will go the opposite direction, but now won't go the opposite way that it did before. So, the chute motor is OK
Next, we assumed the "old" male quick disconnect fitting on the "suspect" valve body connection was not letting fluid pass into the new female quick fitting on the new blower hose. So we eliminated both quick fittings by using two swivel unions. The chute still only goes one way.
Next we put an inline pressure gauge at both chute hoses. On the circuit that does work OK, the gauge shows 1500 as you rotate the chute, then quickly drops as you let go of the joystick. On the "bad" side, the gauge goes up to 1500 but stays at full pressure as you let go of the stick.
So we thought plugged return. We pulled that spool out of the valve body, and everything looks clean.
We then swapped all 4 of the hoses to see if the "suspect spool" could raise/lower the blower, and to see if the chute would now go both directions. The chute now works perfectly both directions, but the when you push down on the blower to lift the front tires off the ground, it stays up, and won't let that lift cylinder to retract, so the tractor gets stuck up in the air.
The crazy part: We took the blower off. We put the front loader back on. The bucket raises and lowers perfect, and the curl/rotation of the bucket works perfect.
... BUT..if we swap those 4 hoses, the curl still works perfect, but when you lift the tractor wheels off the ground by lowering the bucket, the front wheels stay off the ground when you try to raise the bucket. ??
We got out the bucket intallation manual to see if the original bucket valve body hoses were hooked to the tractor correctly when the tractor was new. Like the "pressure beyond" and "pressure", and "return", to the transmission side, and to the fluid block. They match the book.
How can the bucket attachment work perfect, but we keep getting symtoms of a blocked return line on other test hookups?
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