Kubota KX36-3 low hydraulic problems.

[JTP]

Hi All,
Looking for a bit of advice please?

When traveling, the whole arm Assy won't lift or function at all until I stop the travel and the hydraulics will kick in and the arm will function properly.
I have no leaks that I can see and have replaced the main

 

[V8Druid]

duplicate @Regy53

 

[Mick-the-fitter]

Looking at the specs for this machine, when travelling, you won’t get a lot of movement in the boom bucket or dipper, it used a variable plate piston pump to give flow, if using lots of services at the same time the flow would be divided, and if pressure is needed even more of a flow reduction will occur( it’s one or the other! Or a little of any at one time) larger machines do this too!

 

[V8Druid]

Looking at the specs for this machine, when travelling, you won’t get a lot of movement in the boom bucket or dipper, it used a variable plate piston pump to give flow, if using lots of services at the same time the flow would be divided, and if pressure is needed even more of a flow reduction will occur( it’s one or the other! Or a little of any at one time) larger machines do this too!

odd that it used to cope though Mick??

 

[Mick-the-fitter]

You say you had a new pump? All of it including the gear pump ( pilot pump)?

 

[Mick-the-fitter]

Q: do you have the fast track version? And does it work?

 

[JTP]

Hi Mick, yes the gear pump was replaced too, the attached photo is the old Assy that was replaced with a reconditioned Assy.

My one is not the fast track version so can't check that out.

However, the travel has been slowing down a bit as well since I started having the pressure issues.

 

[V8Druid]

Hi Mick, yes the gear pump was replaced too, the attached photo is the old Assy that was replaced with a reconditioned Assy.

My one is not the fast track version so can't check that out.

However, the travel has been slowing down a bit as well since I started having the pressure issues.

couldn't have a better set up that that to get the pressure gauges onto all those Stauffs

 

[Mick-the-fitter]

Ok try something, crowd the boom (up) dipper(in) and bucket, a bit tricky but if you can push both track levers to go forward while hold ing boom back, bucket in and dipper back, what happens?

 

[JTP]

Ok, held the joysticks back in the boom up, bucked in and dipper in positions and pushed the track levers with my knee. The digger travels forward while doing this.

Am interested in what were you looking to happen when doing this? If you are willing to share your knowledge?

Cheers.

 

[doobin]

Ok try something, crowd the boom (up) dipper(in) and bucket, a bit tricky but if you can push both track levers to go forward while hold ing boom back, bucket in and dipper back, what happens?

Left hand yellow!!!

 

[V8Druid]

Ok, held the joysticks back in the boom up, bucked in and dipper in positions and pushed the track levers with my knee. The digger travels forward while doing this.

Am interested in what were you looking to happen when doing this? If you are willing to share your knowledge?

Cheers.

dumping all flow and pressure into the travel circuit - when engaged ... nothing bleeding out to any other services'd be my guess ... once engaged, the Main PRV'd cease relieving and push all flow to the circuit being operated

 

[Mick-the-fitter]

Ok give me 5

 

[Mick-the-fitter]

I think I have an idea, do you mind doing some more tests first? And do you know any one who can measure pressures for you?

 

[Mick-the-fitter]

Lift the boom off the ground, track straight both tracks, use the dipper or slew, then let go and use the boom or bucket( start with the bucket uncrowned and while tracking both crowd in)

 

[Mick-the-fitter]

I think from my Kubota training days, it sounds like your ARV’s are set higher than your Main relief valve, meaning your tracks are running against a higher pressure relief than your main service relief.

 

[V8Druid]

I think from my Kubota training days, it sounds like your ARV’s are set higher than your Main relief valve, meaning your tracks are running against a higher pressure relief than your main service relief.

or the main relief has lost its setting - busted spring .. or some debris in the seat keeping it slightly open ?

 

[Mick-the-fitter]

Yes quite right, oil used for the boom, dipper, bucket and slew is losing pressure.