boom not holding

[Markhodges78]

Do the process you describe but dont start the backhoe.

The weight alone should allow fluid to weep past the piston if that is indeed the problem, and you should see oil coming out the base port as the boom drifts down even without the machine running. If it drifts and no oil comes out that base port....valve is bad. If it drifts and oil also comes out...piston seals are bad.

If it doesnt drift at all......without starting the machine.....then I susmect you have a valve not fully returning to neutral. Which would explain why oil was coming out the base port's hose that was disconnected when you started the machine

Ok When I got home I raised the boom up and hose disconnected hose wiped everything clean put cardboard under machine came back in an hour boom all way on the ground and no oil on card board and no oil at the ram seal to indicate leaking so Im betting its in the valve

 

[Markhodges78]

Im thinking tomorrow I may raise boom and support it while I remove the top hose and put a cap on it that will take the valve out of play and if it holds then we know its in the valve

 

[LD1]

Im thinking tomorrow I may raise boom and support it while I remove the top hose and put a cap on it that will take the valve out of play and if it holds then we know its in the valve

Right now....that top port is the ONLY place the oil went.

Had it bypassed the piston seals....it would have poured out the base end port of the cylinder.

The oil exited the top port, and leaked back through the valve.

 

[Markhodges78]

Right now....that top port is the ONLY place the oil went.

Had it bypassed the piston seals....it would have poured out the base end port of the cylinder.

The oil exited the top port, and leaked back through the valve.

So this would lead me to believe the issue is in the valve correct ?

 

[LD1]

So this would lead me to believe the issue is in the valve correct ?

yes..

 

[ddbackhoe]

This is how the new holland service tech said they check the piston in the cylinder. How would this cause and harm are damage ? It is the function of the machine only difference is the lower line is removed and if fluid come from the cylinder where line was removed it means it逞ｴ getting past the piston. Makes since to me?

Youæ±*e using hydraulic pressure and volume to lift a heavy object. If you inadvertently release the pressure, what happens to the object?

 

[LD1]

Youæ±*e using hydraulic pressure and volume to lift a heavy object. If you inadvertently release the pressure, what happens to the object?

His testing method is fine.

IF he inadvertently releases pressure....same thing happens with hose on or off....load drops. Having the hose off just means oil pours out hose rather than returning to tank