Ive got a 8042 skytrak, about 9800 hours never had any cylinder work to it. The main boom cylinder that extends and retracts the boom makes a high pitch noise when in use. Would anyone know if this is a signal of a problem to come?
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8042 skytrak cylinder noise
- Thread starter bahlborn
- Start date
willie59
Administrator
Yep. 9000 + hours and no work been done to boom, wear pads may be gone. Better remove that rear boom cover and see if there are any wear pads left in there. :yup
wildhorse trnr
Well-Known Member
If the wear pads are intact(which at 9000 hrs. are probably in need of R/R), dead head the cylinder in both directions(once the unit is warmed up) and see if you notice the noise then. Also, try it at low mid and high engine speeds. You should hear the unit bypassing at when you deadhead it.
bcubes
Member
The high pitched noise you are hearing is the counterbalance (holding) valve. The high flow of oil out of the cylinder causes the valve to open and close at such a high rate it produces a squealing noise. This is normal and is not an indication of failure.
willie59
Administrator
Does it make the squeel noise in both directions of telescope, in and out?
willie59
Administrator
Hmm, man, I'm not sure. This is one I'd just about have to be there hearing what it's doing to have any good thoughts of what's going on.
icestationzebra
Senior Member
I have seen two causes for the cylinder squeal. The first cause was counterbalance valve chatter, which is really the valve opening and closing really fast. You normally notice a vibration. Not much you can do except replace the valve.
The second cause was hydraulic oil with poor friction additives. Lull got hit with this in '91 and the remedy was to add a friction modifier to the oil. If you have never changed the hydraulic oil this may be the problem.
I distant third would be bad cylinder seals.
ISZ
The second cause was hydraulic oil with poor friction additives. Lull got hit with this in '91 and the remedy was to add a friction modifier to the oil. If you have never changed the hydraulic oil this may be the problem.
I distant third would be bad cylinder seals.
ISZ