New (to me) YM240D

[woolyAcres]

The 3-point control lever has, starting from the front, three positions. Most forward is Down, fluid drains from the 3-point hydraulic cylinder, through this valve, and back to the sump. Pulling the lever up part way gets to what I call Hold, fluid from the hydraulic cylinder can't escape (aside from worn parts) so the lift stays up or wherever it was, indefinitely.

Note the way these hydraulic systems work fluid is still arriving in Hold position, passing through another part of the 3-point valve and draining to the sump. (So if a loader valve is upstream from this 3-point valve, it has pressure available for its functions). Last position of the 3-point lever is when it is pulled all the way back to Lift, the drain to the sump is sealed and all incoming fluid goes to lift the 3-point. If you hold this position after the 3-point reached maximum height, gauge pressure will spike and the 3-point's overpressure relief valve will squeal. And - this creates backpressure that the outlet of the loader valve, upstream, is facing. Instead of pushing fluid through that valve's outlet and toward the 3-point at its maximum rated allowable 500 psi backpressure, the loader valve is instead facing a 2000 psi backpressure downstream that is limited only by the 3-point's relief valve.

That's generally how I figured it but without the nuances of what's going on when the lift lever is placed in the 'Lift' position and left there.

There's linkage back there that moves the 3-point control to Lift automatically when the arms droop down. This can cause a minor spike but its only chance this could occur simultaneous with lifting something heavy in the loader. And normal ballast shouldn't require full lift pressure to raise, just some moderate amount of hydraulic pressure. Likewise its seldom that the loader will be working at maximum pressure, that should occur only if you hold a loader valve in Lift (or whatever) position after the loader cylinder has reached the end of its travel. Don't Do This.

So while such spikes can occur, I don't think they're important like moving the Lift and loader controls to the end of their range simultaneously. That's the only condition where pressure in each system, 3-point and loader, is limited only by their separate overload relief valves - causing the hydraulic pump to face a 4000 psi load. Don't Do This and you should be fine.

This seems reasonable. I think a few 'Don't Do This' situations aren't a big deal. That's just part of owning/operating an older tractor.

 

[woolyAcres]

@California-

I've been learning so much about tractors in general and Yanmars in particular. I wanted to take a post to thank you for all the time you've put into this thread and all the others you've participated in. You're very generous with your time and an extremely valuable member of this online community. Thank you. I've often been told you don't really understand something until you can explain it to a 5th grader. You're explanations in this thread and others make it clear that you DO understand things and you're wonderful at explaining things. Were you a teacher before you came to looking after the orchard?

Many thanks,
Peter

 

[clemsonfor]

That's generally how I figured it but without the nuances of what's going on when the lift lever is placed in the 'Lift' position and left there.



This seems reasonable. I think a few 'Don't Do This' situations aren't a big deal. That's just part of owning/operating an older tractor.

There are other dont do situations that you can do if you wanted and probably would not tear anything up the first time you did it but over time might.

Example. You dont shift in and out of gear and engage your pto with the tractor at 2000rpm.
You dont put the throttle in total wide open and just go about your day cutting and whatever no matter what the conditions are at hand.
You should not use your loader or boxblade like a bulldozer.

 

[clemsonfor]

That's generally how I figured it but without the nuances of what's going on when the lift lever is placed in the 'Lift' position and left there.



This seems reasonable. I think a few 'Don't Do This' situations aren't a big deal. That's just part of owning/operating an older tractor.

There are other dont do situations that you can do if you wanted and probably would not tear anything up the first time you did it but over time might.

Example. You dont shift in and out of gear and engage your pto with the tractor at 2000rpm.
You dont put the throttle in total wide open and just go about your day cutting and whatever no matter what the conditions are at hand.
You should not use your loader or boxblade like a bulldozer.

 

[California]

There are other dont do situations...You should not use your loader or boxblade like a bulldozer.

That's one's not obvious, and I've seen posts where someone bent the front edge of the bucket trying to bulldoze, dig, or move a rock etc with the front edge of the loader bucket turned vertical down. Don't Do This. The floor of the bucket should be near horizontal before pushing the front edge against anything. I'm glad I read that before making that mistake.

 

[California]

@California-... Were you a teacher before you came to looking after the orchard?

Nah. Well a little. Only time I was a classroom instructor was teaching auto shop in a vocational high school, in South America. (Peace Corps).

Wrote a lot of political analyses and forecasts as undergrad (PolSci), same in the financial realm later in grad school (MBA). These are examples where it is necessary to explain complex subjects so clearly that nobody is going to argue some other conclusion from the facts.

 

[clemsonfor]

That's one's not obvious, and I've seen posts where someone bent the front edge of the bucket trying to bulldoze, dig, or move a rock etc with the front edge of the loader bucket turned vertical down. Don't Do This. The floor of the bucket should be near horizontal before pushing the front edge against anything. I'm glad I read that before making that mistake.

good way to be cylinders and the top end of the bucket. Maybe it is not obvious. Its a farm tractor loader not a backhoe or bulldozer. Not talking to you (meaning not trying to make you feel dumb or stupid), but if more people that do it...if they would just think things through and what forces are exerted where.

 

[woolyAcres]

@California-

Sounds like you've lead an interesting and rewarding life. I'm glad your now free to pursue what interests you, and I'm especially glad those old Yanmars are one of those interests.

 

[woolyAcres]

So I finally had time and parts today to get the front/dump cylinders rebuilt. The leaking from the front of the one cylinder has stopped. That's the good news. The bad news is there are other new leaks, most notably one of the flex lines didn't take well to being moved. Fluid is 'bleeding' through the exposed metal braid. All those hoses are pretty rough but I was hoping I could at least get it back together and see an improvement. The only thing that looks to have improved is the leaking down the cylinder arm. The loaders ability to lift seems pretty unchanged. I suppose the next step is to rebuild the two lift arm cylinders. They appear to be exactly the same as the dump cylinders but longer. I've got a few left over parts from the front cylinders and I know what to order for the rest of the seals.

I'm fairly convinced that something is wrong with the loader control. When there's any load in the bucket, or force needed to move the bucket, moving the levers does next to nothing- no squealing, no movement, no shuddering etc. It almost feels like the control lever on the controller should move further but it will not. However before dealing with the controller I think I'll repair the rear cylinders first and see what that does. It can't hurt and it's less expensive.

Is there a way to test that my repairs to the front cylinders helped? For instance, leaving the bucket partially rotated and watch for it to drift down.

Again, thanks for all the input so far. I think I'll get it working right eventually. A tractor this age/cost, it going to have some bumps along the way.

 

[woolyAcres]

The truly unfortunate thing today was I managed to sheer off the PTO lever. This is the one that's bound up on the shaft that is used to engage the diff-lock. Well, I've been hitting it with penetrating oil for a week or more and that wasn't having an effect so I decided to put some heat on it. I must have given it too much heat because when I stood on the diff-lock lever with one foot and pulled up on the PTO lever to break it free, it just broke off in my hand. Hopefully this is something replaceable from Hoye's. The real problem is that darn thing is still stuck on there and I just can't get it to budge. I'd use a wheel-puller but I don't think I can get the fingers between the stuck lever and the wall of the transmission. I'll have to see about cutting a seam in what's left of the lever and maybe pry it off?