Kubota K008-3 Dipper Arm Slowly dropping

[L7EWB]

Hi Guys, I’ve recently purchased a K008-3 and today I’ve noticed that dipper arm slowly drops while using it, I've topped up the hydraulic oil and cannot see any leaks etc? Any ideas what this could be?

Thanks

 

[Regy53]

usually the ram will be letting by

i take it this is with the machine running, only other thing is maybe a spool not closing fully

 

[L7EWB]

usually the ram will be letting by

i take it this is with the machine running, only other thing is maybe a spool not closing fully

Thanks, it continues to drop if you switch the Machine off also?

 

[Bri963]

Most likely the spool

 

[Mick-the-fitter]

How good are you with spanner’s? We can have a go at diagnosing the fault, using another service!

 

[V8Druid]

How good are you with spanner’s? We can have a go at diagnosing the fault, using another service!

why not support the boom and cap off the bottom ram port, then knock the support out .. would 'prove' the ram seals, if it didn't drop ..... (put an Acrow under it to re-connect if it doesn't drop)

 

[Mick-the-fitter]

why not support the boom and cap off the bottom ram port, then knock the support out .. would 'prove' the ram seals, if it didn't drop ..... (put an Acrow under it to re-connect if it doesn't drop)

Exactly for an internal leak, usually it will be the o ring between rod and piston on that ram, using the boom service to operate the dipper would eliminate check valves and or spool.

 

[Russell]

I thought if the ram leaked internally it wouldnt move too far because of the displacment of the rod itself?
The theory being if more rod goes into the cylinder it would want to (but couldnt) displace the oil and so would stop sagging.
And therefor if a ram drops then the spool must be leaking internally?
Im not arguing, just curious.

 

[V8Druid]

I thought if the ram leaked internally it wouldnt move too far because of the displacment of the rod itself?
The theory being if more rod goes into the cylinder it would want to (but couldnt) displace the oil and so would stop sagging.
And therefor if a ram drops then the spool must be leaking internally?
Im not arguing, just curious.

depends how far it drops, but yes there will be a limit ... unless as said, the oil can escape from the gland end of the cylinder .... if it drops fully then there is an issue with the spools bypassing

 

[CPS]

A ram will drop fully with a bad seal.

 

[V8Druid]

A ram will drop fully with a bad seal.

how can it drop fully with the rod taking up perhaps 30+% of the gland end of the cylinder's volume .. the full cylinder of oil has to go somewhere as it bypasses and can't be compressed into a smaller volume? it might bypass enough to put the bucket back on the deck with the dipper out stretched though

 

[hiluxman]

how can it drop fully with the rod taking up perhaps 30+% of the gland end of the cylinder's volume .. the full cylinder of oil has to go somewhere as it bypasses and can't be compressed into a smaller volume? it might bypass enough to put the bucket back on the deck with the dipper out stretched though

Boom ram on k008 is fitted other way round.

 

[Canal Navvy]

OP said dipper ram so pulling air past the rod seal would sound possible ...might be evidenced by cloudy hydraulic oil

Suggesting seals inside the ram faulty

 

[V8Druid]

Boom ram on k008 is fitted other way round.

ah right ... in that case it deffo would

 

[Mick-the-fitter]

If drawing air in then would leak oil out!

 

[Canal Navvy]

If drawing air in then would leak oil out!

Lip seals?