Boom trouble

B

Buchanantreeservice

Location
Johnstown
Hi I just bought a 1997 gmc asplundh c7500 no owners manual so I'm figuring it out on my own till it gets here but I bought a hydrolic pole saw and I hooked it up to try it out and disconnected it now my boom wont raise does everything else but won't raise using the controls in the bucket the deck control works to raise it. It was low on hydrolic fluid but I filled it up and still nothing any suggestions what it may be?
 
Make sure that the emergency shut off valve is all the way up. If it doesn’t work freely, free it up. If the valve is slight pushed in, you will get some pressure, but not enough to raise the boom.
 
RTS said:
Make sure that the emergency shut off valve is all the way up. If it doesn’t work freely, free it up. If the valve is slight pushed in, you will get some pressure, but not enough to raise the boom.
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Yes it's up the whole way if I have someone work the lower control at the turn table when the top section of the boom is about to break over center I can control in the bucket I can go the whole way up and over and lift it all the way back up and over it will lift as long as no one is in the bucket but as soon as there is weight it won't lift
 
It was low on hydro fluid and has reduced power (can lift an empty bucket but not an operator) have you checked for visible leaks? Could also be an internal leak in the cylinder
 
There's no signs of leaks at the cylinders or lines but can hear air or a whistling noise in controls in the bucket but hit the stop it goes away but as soon as u pull it it restarts. It does everything else while I'm in the bucket it rotates and moves it just wont lift I have to have someone lift it at the turn table it's just the lifting that is acting up
 
Buchanantreeservice said:
There's no signs of leaks at the cylinders or lines but can hear air or a whistling noise in controls in the bucket but hit the stop it goes away but as soon as u pull it it restarts. It does everything else while I'm in the bucket it rotates and moves it just wont lift I have to have someone lift it at the turn table it's just the lifting that is acting up
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Doubtful that it is air, but it may be hydraulic fluid running through. I assume the boom worked before testing the polesaw? If hydraulic fluid is running and the boom worked before then its possible your tool switch is stuck in the tool position instead of the boom, could be stuck internally. You could also have a bad seal in the bucket controller letting fluid bypass.

If it is the switch being stuck I wonder if you could hook the saw back up, with the switch in the boom position, and check for saw function. If the saw runs then the fluid is being diverted to the tool instead of the boom.
 
Make sure the emergency shut off works freely, the are known to seize up. It only has to be down a fraction in order for it to restrict flow.
As mentioned above it could also be in he tool selector valve. If it is not sitting in the detention all the way, it also could restrict some pressure.
 
Jehinten said:
Doubtful that it is air, but it may be hydraulic fluid running through. I assume the boom worked before testing the polesaw? If hydraulic fluid is running and the boom worked before then its possible your tool switch is stuck in the tool position instead of the boom, could be stuck internally. You could also have a bad seal in the bucket controller letting fluid bypass.

If it is the switch being stuck I wonder if you could hook the saw back up, with the switch in the boom position, and check for saw function. If the saw runs then the fluid is being diverted to the tool instead of the boom.
Click to expand...
Yes it ran fine until I tested the pole saw and I hooked the pole saw up again and it worked but the bucket still won't lift using the bucket controls
 
Is the upper boom control lever bottoming out when you pull the lever? Make sure that it is not hitting the hoses when you pull back on it, thus not allowing it to go all the way.
 
The levers have bends in them & are locked into place with a lock nut. The bends have to be at 3 & 9 o’clock. Running out of options. You have it narrowed down to one function in the upper controls; the upper boom unfold and it can only be a few things. You can try calling Altec support..(877) 462-5832
 
RTS said:
The levers have bends in them & are locked into place with a lock nut. The bends have to be at 3 & 9 o’clock. Running out of options. You have it narrowed down to one function in the upper controls; the upper boom unfold and it can only be a few things. You can try calling Altec support..(877) 462-5832
Click to expand...
Thank you I should know more Monday when I get back to job it's on a jobsite
 
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