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Bobcat 843 Hydraulic Controls Malfunction

smitty66212

New Member
Joined
Jan 22, 2017
Messages
1
Location
Kansas City
Hello, brand new to the forum and just bought my first skid steer ever, Bobcat 843. I bought it with hydraulic issues, but not really sure what I was getting into.

The left foot (lift) is not working at all, doesn't cause lifting arms to move. The right foot (tilt) will work the cylinder when there isn't a bucket on it, if bucket on it, it will not lift the machine off ground when you tilt down. When you curl the tilt to the fullest, then the loader arms will lift up, when nothing is touching left foot peddle. Also, when you pull the right steering lever in towards your thigh (auxiliary function), the loader arms will lift up and no foot peddles are being pressed.

Where do I start to diagnose this, could this be the control valve spools leaking across circuits, or could this be a relief valve issue?

Appreciate any help, I am determined to fix this myself even if it takes me a few months. I want to learn about these machines.
 

franklinute

Well-Known Member
Joined
Dec 1, 2010
Messages
94
Location
Winchester, TN
I would start by checking that the seat bar is all the way down and that it engaging
the release arms that allow the foot controls to work. The auxiliary hyd lever will operate
toward you thigh but will also operate away from your thigh and can lock in. Be sure that
is in the middle. Raise the cab and be sure the linkage is in good order and that the poly
bushings are in good shape. If all that is good then I would proceed to the control valve.
 

Vetech63

Senior Member
Joined
Aug 10, 2016
Messages
6,465
Location
Oklahoma
You have at least one bad cylinder piston packing. The control valve is an open centered closed port design. When you mash the pedal for one control, the oil getting past the bad packing is feeding the other circuit. Not sure on the steering as that is operated by piston pumps driven off the back of the engine, and the small gear pump on the back of those is the implement pump. I would bet you have cylinder packing material in some of the load checks, reliefs in the hydraulic system.
 
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