Cat 962H no hydraulics

[wee_gus]

hi guys looking for a bit of assistance, currently have a cat 962H 2008 vintage with 14k hours in the workshop.
Very poor hydraulics on the loader and bucket functions, each function only moves 10-20 mm when try to lift, tilt or dump. Will also not lower.
We have checked various valves etc but are now stumped.
Pilot pressure is good and so is pump margin pressure according to cat spec
Pilot 300Psi
Margin 295PSI

we did get loader to lift and dump twice randomly but hasn’t done it again.
We feel the pump is good as it did this but we aren’t 100%

 

[Quattromike]

What is the pump on this, is the load sense line burst/leaking/nipped somewhere

 

[wee_gus]

What is the pump on this, is the load sense line burst/leaking/nipped somewhere

It’s a variable displacement piston pump that’s run off the top of the transmission, no access would need to remove the cab to access pump.
We have checked but can’t see anything. Only thing we did find was a very slight score on the duplication valve but we don’t think this would effect it as essentially it’s a balance valve

 

[JD450A]

Check Valves?

 

[CPS]

Was it cold when the loader lifted? Does it have a Aux line ?

 

[Quattromike]

Is it just the loader that not working, is there any other services that you can operate at the same time to see if pump swashes up? Is the motor labouring when you're operating the loader functions or not pumping?

 

[wee_gus]

Check Valves?

No check valves

 

[wee_gus]

Was it cold when the loader lifted? Does it have a Aux line ?

Yes hydraulics cold, no aux

 

[wee_gus]

Is it just the loader that not working, is there any other services that you can operate at the same time to see if pump swashes up? Is the motor labouring when you're operating the loader functions or not pumping?

Just loader as this runs of separate pump, just about all systems have their own pump. When I operate the levers it goes into high idle

 

[Bri963]

hi guys looking for a bit of assistance, currently have a cat 962H 2008 vintage with 14k hours in the workshop.
Very poor hydraulics on the loader and bucket functions, each function only moves 10-20 mm when try to lift, tilt or dump. Will also not lower.
We have checked various valves etc but are now stumped.
Pilot pressure is good and so is pump margin pressure according to cat spec
Pilot 300Psi
Margin 295PSI

we did get loader to lift and dump twice randomly but hasn’t done it again.
We feel the pump is good as it did this but we aren’t 100%

Just had a similar issue with a 938. Check the linkage and cable to the self-levelling sensor on the bucket linkage, as that was what caused the issue on ours. May be the actual sensor, they can cause all sorts of unexpected issues.

 

[wee_gus]

Just had a similar issue with a 938. Check the linkage and cable to the self-levelling sensor on the bucket linkage, as that was what caused the issue on ours. May be the actual sensor, they can cause all sorts of unexpected issues.

What sensor did you have was it the rotary type?? How did you pinpoint it to this?

 

[Bri963]

Rotary type, the linkage had fallen off, due to a missing nut.

 

[wee_gus]

Rotary type, the linkage had fallen off, due to a missing nut.

Will get the cover off tomorrow and have a look

 

[V8Druid]

my two penn'orth ... when I had the load sensing line issues a while back, it was giving very similar symptoms. eventually traced to a rubber crumb in a 0.6mm orifice in the LS line, where it was fed from the main valve block - stripped, cleaned and LS line renewed, cured the issues .. been fine since (touch wood) ...... Drema would move a little at a time, in all load sensed motions, then go again, etc., etc.. ...... took a lot of finding

 

[Canal Navvy]

Once saw a jcb with similar odd behavior that was caused by the nut that holds the piston to the rod coming loose inside one of the lift cylinders

 

[Quattromike]

Did you find out what the issue was on this @wee_gus

 

[Bri963]

Guess we’ll never know.

 

[V8Druid]

Guess we’ll never know.

why? where's Gus ?

 

[Bri963]

Good question.