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
Double check and make sure you didn't cross lines when you removed the lift cylinders. Lift will always take precedence over lowering if the lines are hooked up wrong.
Thanks for the input, unfortunately that's not it, the hoses had so much memory they stayed pretty much in place when I took the cylinders out. I straightened the hoses out to see if it would be possible to hook them up in reverse, but they are different lengths and wont reach. Has anyone ever come across one of these valve bodies that had an internal crack?
I'm struggling to get the lift cylinder ram out, any suggestion?
Remove both hoses. Sometimes you have to use a come-a-long or even a ratchet strap to pull the rods out.
ive seen control valves with (what we assume) is internal cracks, only way to solve an issue is replace the valve. i'd pull both the aux stems and electrically test, they should be making a buzzing noise when they are activated. one of them may be stuck "on" and causing some of your issues