Autocrane boom drift

[komatsukid]

Hello, I have a Autocrane 4004eh and the boom drifts down without any load on it. Any ideas where to start ? I’m not much of a crane technician. Thanks.

 

[Elmeche]

You can change the hydraulic hoses of the boom to other valve only for trying. If the boom is not drift => the boom valve is the problem - maybe leak or worn out or dirty. If not => the internal seals in the cylinder.
Of course if there isn't outside leak of oil.
Has the cylinder of the boom locking valves on it?

 

[CraneMechanic73]

Boom up a bit. Find your extend and retract lines going to cylinder. Remove both lines. If the exposed ports keep continuously drip oil, most likely it’s the holding valve. If the oil doesn’t continuously drip from the ports, then it’s your cylinder packing. That’s always been my starting point.

 

[Elmeche]

Boom up a bit. Find your extend and retract lines going to cylinder. Remove both lines. If the exposed ports keep continuously drip oil, most likely it’s the holding valve. If the oil doesn’t continuously drip from the ports, then it’s your cylinder packing. That’s always been my starting point.

Absolutely right, but for novice in this area it is very dangerous procedure depend of the state of the boom cylinder or hold valves. May be he has to use a jack for support and slowly lower a bit and pay attention for hoses not to spill oil in the eyes.

I’m not much of a crane technician

 

[CraneMechanic73]

absolutely be aware and take precautions when working on hydraulics. I was just relaying where the usual start point is on boom drift……

 

[komatsukid]

Thanks for the replies, found out it was to load holding valve. Replaced it all is good! Thanks again.