I have a bobcat 773G with foot controls that's giving me a hard time. The problem seemed to start when one of the lift cylinders had a piston seal go bad and started to bypass. I removed both lift cylinders and replaced the seals, tested them and put them back in the machine.
When I started the machine, everything seemed to work except the boom would not lift unless you would roll the bucket back at the same time. so I pulled the valve body out to pull it apart and see what was going on.
Everything seemed to look ok, with the exception of a little piece of the lift cylinder seal stuck on the aux spool when I pulled it out. Thinking this must have been keeping the spool out of center and causing my problem I reassembled the valve body with new spool seals and o-rings.
When I started the machine, another problem, now with the seat bar down to unlock the pedals, but before I press the "press to operate" button The tilt is locked (as it should be) but the boom will operate in reverse direction of normal (heel lowers, toe raises) When I press the button to unlock the bics, the drive and tilt work normally but the boom will raise in either direction you move the pedal. The only way to get it down is to just slightly move the pedal back and forth in both directions (not more than a quarter of the travel, if you move it more then that it will raise)
also the tilt cylinders will leak down when the machine is off, but not when running
The machine does not have a bucket position valve, power bob-tach, or diverter valve
I've replaced both bics lock valves, the bics stem and coil, and the bics check valve, made no difference. bics coil is getting 12 volts when activated
checked all four cylinders again, all fine
Plugged lines going to lift bypass valve, made no difference
put a hose in to connect aux. quick connects, no difference
removed bics valve and checked all three load checks, all seem fine
removed all three spools again to check for any more debris, couldn't find any. aux spool centering springs ok, cleaned lift spool float detent and replaced springs and balls
swapped the port relief and anti-cav valves for lift/tilt, made no difference
swapped aux stems, no difference
I'm hoping someone on here might have some insight or ideas because I'm running out of them, other than the valve body has a crack internally, but that seems unlikely to me
serial number 517614715
When I started the machine, everything seemed to work except the boom would not lift unless you would roll the bucket back at the same time. so I pulled the valve body out to pull it apart and see what was going on.
Everything seemed to look ok, with the exception of a little piece of the lift cylinder seal stuck on the aux spool when I pulled it out. Thinking this must have been keeping the spool out of center and causing my problem I reassembled the valve body with new spool seals and o-rings.
When I started the machine, another problem, now with the seat bar down to unlock the pedals, but before I press the "press to operate" button The tilt is locked (as it should be) but the boom will operate in reverse direction of normal (heel lowers, toe raises) When I press the button to unlock the bics, the drive and tilt work normally but the boom will raise in either direction you move the pedal. The only way to get it down is to just slightly move the pedal back and forth in both directions (not more than a quarter of the travel, if you move it more then that it will raise)
also the tilt cylinders will leak down when the machine is off, but not when running
The machine does not have a bucket position valve, power bob-tach, or diverter valve
I've replaced both bics lock valves, the bics stem and coil, and the bics check valve, made no difference. bics coil is getting 12 volts when activated
checked all four cylinders again, all fine
Plugged lines going to lift bypass valve, made no difference
put a hose in to connect aux. quick connects, no difference
removed bics valve and checked all three load checks, all seem fine
removed all three spools again to check for any more debris, couldn't find any. aux spool centering springs ok, cleaned lift spool float detent and replaced springs and balls
swapped the port relief and anti-cav valves for lift/tilt, made no difference
swapped aux stems, no difference
I'm hoping someone on here might have some insight or ideas because I'm running out of them, other than the valve body has a crack internally, but that seems unlikely to me
serial number 517614715
Bobcat 773g lift problem
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