I have been extensively chasing an lx565 boom issue. It will lift and lower perfectly sometimes, other times it will lift slower than normal, when it does this, I know it’s going to act up. The acting up: when I release the pedal after it lifts slower than normal, the boom will start to settle down immediately. If I go to lift again and press the pedal lightly, it will drop first, until I push the pedal harder to overcome the force of it dropping, and it will lift then (all in the matter of a couple seconds or less of course). I can rock the pedal back and forth a bunch and it will correct itself. There’s no consistency to this. Warm or cold it will act up. It seems that if I take the boom all the way up and to relief, it will then settle when I bring the boom down and release. Often does the same on deadheading the boom down. But not always, that’s the hard part. I have had times when I was lifting, and it was doing its slow lift, then it snaps out of it and speeds up. So now I know that when I release pedal, the boom will stay put, and it does. It’s not something simple, well maybe it is, but I’ve gone through a lot of scenarios. The load check valves (spring poppets) can’t be an issue, I understand the slight dip before lift issue when it acts up, but I completely removed the load check and now it would always “dip before lift “ but not always settle. So they aren’t an issue. I don’t believe the main relief pressure valve is an issue because the tilt does not behave in this way, it’s strictly in the lift function. I also replaced it with an aftermarket one that didn’t fit quite right, but didn’t change the symptom either. I was thinking the lift relief cartridge on back of control valve, right above lift spool. I took that out. Took it apart and inspected, with no signs of wear or debris. I did count the turns on the relief pressure and dialed it right back in exactly. I borrowed a cartridge off a friends ls160, and my machine acted the same way, and theirs performs as it should. I don’t feel it can be internal cylinder seals because it’s intermittent. They don’t randomly seal and other times leak. The spool locks work as should, they’re either unlocked or locked. There’s cavity plugs in the front, I inspected all those seals, look good. It has to be something mechanical that is malfunctioning at times. One suggestion was a worn grove in the spool valve bore. And sometimes at top pressure, it will shift the spool into this worn grove allowing oil to bypass in both directions, until a snap the spool back and forth a lot and it snaps back into its factory bore. I just am not sure I can convince myself of this, but maybe others have seen this to be true? If so I’m kinda screwed because I’m not buying a new control valve for this machine. I tried two other lx565s I know of in the community. The crazy thing is both do the same dang thing. So clearly this is a common problem, but no dealer can tell me the solution. Any help would be appreciated. Thank you!!
Unfortunately it’s probably the spool. Take it out and get a look at it. I have cleaned up a few spools that would stick and with new O-rings, they worked fine.
I’m under the impression this spool does not have orings. Most of these in my experience is a bore fit and metal to metal. The spool itself is not sticking outside of center if that’s what you’re referring to. I can visibly see it returning to center and lining up with tilt spool every time I release pedal. Not saying you’re wrong! I’m just not thinking it’s a lack of centering issue. Appreciate your input!