690 E LC stutter

[jbzoner]

I'm hoping that someone on this forum can provide some insight. I have a '95 John Deere 690 E LC that has a "strange" stutter/flutter- heck if I know what to call it... On the main boom (the one closest into the operator station), when descending without a load- there is almost a 'step' function as the cylinders compress. I can hear the bleed off from the hydraulics, and it's inconsistent, matching the bouncing of the arm coming down. To put it another way- when going down, the bouncing of the arm is enough to shake the entire machine, even well bedded and stable. On uneven ground- yikes!

The problem is NOT consistent. Only occurs when system is warm (about after 25 minutes of operation). I have replaced the spool filter (and cut it open- nothing of note).

Been to talk to the dealers and mechanics in the area- no help.

Any ideas?

[Nac]

Maybee to holding valve on the cylinder is sticking

[dayexco]

dumb question, could you have a slug of air in that circuit? a hoist circuit really wouldn't be a circulating circuit, possibility of air trapped there?