mclean
Well-Known Member
Put a used Jones thumb on a cat 312 excavator. The cylinder hisses when extending?
Its all -12 hose and fittings, there is an adjustable relief valve between a/bb hoses just after the valve block. Goes away as the psi is dropped.
Hisses at an idle, screams at operating rpm.
Cylinder moved freely when It was loose.
Blead the fluid and there were some bubbles.. But noise stayed.
When I was bleeding fluid, I noticed there didn't seem to be any hold psi on the extend circuit.
Any ideas?
Its all -12 hose and fittings, there is an adjustable relief valve between a/bb hoses just after the valve block. Goes away as the psi is dropped.
Hisses at an idle, screams at operating rpm.
Cylinder moved freely when It was loose.
Blead the fluid and there were some bubbles.. But noise stayed.
When I was bleeding fluid, I noticed there didn't seem to be any hold psi on the extend circuit.
Any ideas?