873 lift arm wont stop

[dodgeking3171]

Hey guys, Newer to the forums. The neighbor down the street has a bobcat 873. I havnt looked at it yet nor am I much of a newer bobcat man. The problem is that when they lift the arms and let off the valve, the arms keep going up. I havnt looked at it myself much. They took it to a local dealer and they say they "cant figure it out" This is a 2 speed machine and like i said i havent looked at it myself but what could this lead to? im my mind its the control valve easy and simple. but i figured id ask if there was anywhere that they share another valve that could bypass and keep the loader arms going up. Neighbor says the control valve is about 5k so hes hoping its not that haha

 

[Tazza]

It could be a control block issue, but for the dealer to not know what the issue is, sounds like it may be more than that.
If it has hand controls, it could be an actuator issue holding it to the arms keep lifting.
Could be a broken spring in the control block, could be something binding up keeping it from going back to neutral too.

 

[dodgeking3171]

It could be a control block issue, but for the dealer to not know what the issue is, sounds like it may be more than that.
If it has hand controls, it could be an actuator issue holding it to the arms keep lifting.
Could be a broken spring in the control block, could be something binding up keeping it from going back to neutral too.

this loader is a hand control. but i have no experience, are they all pilot controls? or is there a linkage? you say the actuator could be holding it open so i assume they are pilot controls.

 

[jerry]

this loader is a hand control. but i have no experience, are they all pilot controls? or is there a linkage? you say the actuator could be holding it open so i assume they are pilot controls.

Have them try a loop hose from coupler to coupler on the aux hyd. A friends 853 did this and we cured it temporarily that way. I know it is a different machine but doesnt cost anything to try. The odd thing was that the engine did not labor or act as though the aux was engaged. To cure it they took the solenoids out and cleaned them. They had the tilt cyl seals go twice before that and parts of the seals went into the system which I think caused it.

 

[jerry]

Have them try a loop hose from coupler to coupler on the aux hyd. A friends 853 did this and we cured it temporarily that way. I know it is a different machine but doesnt cost anything to try. The odd thing was that the engine did not labor or act as though the aux was engaged. To cure it they took the solenoids out and cleaned them. They had the tilt cyl seals go twice before that and parts of the seals went into the system which I think caused it.

If the loop works just leave it on till time allows fixing it. My friend's would boom would go up and not stop and would not come down until the engine was stopped.

 

[dodgeking3171]

If the loop works just leave it on till time allows fixing it. My friend's would boom would go up and not stop and would not come down until the engine was stopped.

If the loop works will the machine work otherwise? Where do the two systems intersect at? Im a old school loader guy and I dont see where they would meet

 

[jerry]

If the loop works will the machine work otherwise? Where do the two systems intersect at? Im a old school loader guy and I dont see where they would meet

Yes my friend ran his about 2 months with the looped hose on it till the weather was better. The aux and lift and tilt get their oil from the hyd pump, the drive is basically a closed loop with only makeup oil added at charge pressure from the hyd pump. I know it doesn't sound right but I got the idea here at this forum so we tried it and it worked. His bucket at times would also tilt even with the machine off, it was a goofy deal. If you have a hose and couplers it is a easy was to eliminate the aux circuit as a problem.
But then again we pretty much operate on dumb luck and guesswork here in northern mn.