Loader valve difficulty

[284 International]

I just purchased a Yanmar YM240 with a loader 2 days ago. When I bought it the motor was partly disassembled, supposedly to replace a headgasket. I got it back together and running, though my motor difficulties will probably end up in another thread, but for now, my trouble is with the loader valve. The lift works fine, but seems to lug the engine until everything is warmed up. The bucket curly, however, seems to really load the motor. It curls easily, but when trying to dump the bucket the valve won't move. Applying a LOT of force, or bashing the lever in frustration, sometimes lets the valve move and dump the bucket. The motor lugs when that happens, and feels like it may stall, and no matter what, the bucket is EXTREMELY slow. Letting off the valve brings the motor up to speed again. Where should I start looking? Thanks in advance for your help.

Edited to add: The loader is powered by a separate pump driven off a chain drive from the crankshaft, not by the 3 point hydraulics.

 

[winston1]

Being in Southern California I don't understand why your loader is slow until warmed up. Proper hydraulic fluid shouldn't require warm up to operate normal. It does sound like your loader valve is not functioning right. Sounds to me like your going to have to take your valve apart, clean it up and install new o-rings or whatever.

 

[284 International]

I'm not sure why it works better once it's warmed up. I didn't do a good job of explaining, I guess: The loader's speed is good all the time, but something simple like lifting the bucket bogs the motor down and it wants to stall. After a few minutes of briefly using the loader in one or two second bursts, it goes up and strongly and lifts several hundred pounds without difficulty. The fluid appears clean and clear, but I don't know if it is the correct fluid. I will replace it after I fix the valve.

I'm very ignorant about hydraulic systems. Is there a how-to on rebuilding the valve? Pitfalls to avoid? I'm fairly mechanically inclined but have no knowledge of these devices. The travel of the little slide connected to the lever on the bucket curl side is much less going in (dump) than it is going out (curl), and that's where the problem appears to be. I'm frustrated by this tractor in a multitude of ways, but have heard and experienced good things about Yanmars, so am not willing to give up quite yet. Thanks again.

 

[mmurphy]

If there is quick disconnects on that bucket valve, unhook and rehook. May possibly not be seating right. Make sure you rest bucket on ground and shut tractor off. With tractor off, work the valves to see if they free up, plus that should help bleed pressure off. Try a couple times if needed.

 

[winston1]

I am not aware of a "how to rebuild" sight but depending on make and model you might find a parts list out there or drawing to help you. Here is a Prince sheet on valves that would be similar to yours. I have no first hand experience on these valves. http://www.princehyd.com/Portals/0/products/valves/RD5000Manual.pdf

 

[normde2001]

Swap the lift and curl lines and see if the problem stays with the curl cylinder or moves to the lift cylinder. OOPS! I see in the follow-up post the problem is in lift and curl both. I would replace the fluid.

 

[284 International]

After Christmas festivities are done this morning, I'm going to attempt to disassemble the valve. It seems like the main trouble is with the dump/curl spool. Something is restricting its travel, and keeping the dump cylinder from getting enough flow as a result. Assuming I can discover something and then correct it, I'll flush the system and replace it with fresh fluid once I have access to a store that sells hydraulic fluid.

 

[winston1]

Keep us informed, I'm interested in just what is wrong. Merry Christmas.

 

[California]

I've read that hydraulic controls are made with clearances so tight that no o-rings are used. You can disassemble and clean but replacement is the only way to remedy excessive wear. Northern Tool sells suitable valves around $200. But if yours isn't dribbling then there's no need to replace it.

My guess is the problem is debris inside the valve. When I replaced a hose I found a big chunk of o-ring that wouldn't pass a tight spot from a return line back into the valve, so that is the first thing I would suspect here.

Was that the Yanmar on Craigslist-Hanford?

That's a great model tractor and you will love it after you get it sorted out. If you would like to see Yanmar-USA's original sales brochure/specifications, click on the link at the bottom of this post.

Welcome aboard, and Merry Christmas!

 

[284 International]

I am preparing to dive into the valve assembly now. Hopefully it will be productive.

California, I was hoping to hear from you. I read about your experiences with your YM240, and it encouraged me to look in that direction. It is the tractor from Hanford. I'm concerned that I bought a lot more of a lemon than I anticipated. The motor is spewing dark gray/black smoke and lacks power, a new and sudden development from when I first assembled the motor and it ran strongly. I'm wishfully thinking and hoping it will somehow clear itself out of this condition, but I'm really doubtful. I'm going to need help getting it running properly here in the near future.

 

[284 International]

Success! After struggling some to remove the hoses from the valve, I got the spool out. It came out in a straightforward fashion: Pull the cap on the opposite end from the lever, and, after unpinning the lever, pull the spool out. It has a spring on one end, retained by a bolt and washers on the spool and bolt head ends.


As you can see by the attached photograph, the spring was filthy with a tar-like crud, and inside the cap the crud had congealed into a crusted layer of carbon. It looked and felt just like the crust in the bottom of an oven if pie boils over. I gently scraped everything as clean as possible with a rifle brush, then dunked it into my ultrasonic cleaner. I ran it all for a 6 minute cycle in warm mineral spirits, and everything came out relatively sparkling. I reassembled it all, and now the valve works fine! Now if I could only make the motor run properly....That will be another thread, find it here: YM240 smokes heavily, lacks power - TractorByNet.com

Thanks for all your help.



http://i1108.photobucket.com/albums/h407/International284/Spoolreturnspring.jpg

 

[California]

I'm glad to hear that was easy to fix - basically doing the maintenance that had been neglected for a couple of decades.

My YM240 had several gotchas like that when I bought it. A month of tinkering got it back to decent condition. The primary problem in my case was it contained ancient fuel that would hardly burn. I suspect it was parked 10 years. The short-term second owner burned up and replaced the starter, buggered the clutch safety switch and the ignition switch, discarded the whole fuel filter assembly, put a 'reconditioned' battery in that was worthless, and had done other ineffective butchering without resolving this simple underlying problem. After I spent a couple hundred dollars to get back to stock condition and do a major maintenance cycle including fresh fuel, it became the nice tractor that Yanmar intended. (Well except for the weathered paint!)

I'll go look at your other thread now.

 

[284 International]

As you said, California, it appears that I need to do some of the basic maintenance and service that should have been done every couple hundred hours. I've found some other sorts of farm-expedient repairs or "service" jobs now that I've looked more closely and know what to look for. I'm tempted to start a thread on a list of all the "don't" or what to look out for when buying a used tractor. I don't want it to seem like I know what I'm talking about, though, so will document and record my experiences as I go, just in case.

I should have known better than to take someone's partly disassembled used tractor, so it's all my fault. For what it's worth, the guy I bought it from said he was moving, and had to be out quickly, and when I showed up he did have a crew loading stuff into a large moving truck. The story all went together, so I don't want to badmouth anyone without proof, especially since it's public record where and how I got the tractor. It's discouraging to feel taken advantage of, though, because I essentially took his word that I would have to reassemble the top end of the motor and then chug happily off into the sunset. Oops. Thanks again for the advice and tips. I think there is a lull in the rain here, so I'm going to plug away on the motor issues.

 

[careyo63]

I'm glad to hear that was easy to fix - basically doing the maintenance that had been neglected for a couple of decades.

My YM240 had several gotchas like that when I bought it. A month of tinkering got it back to decent condition. The primary problem in my case was it contained ancient fuel that would hardly burn. I suspect it was parked 10 years. The short-term second owner burned up and replaced the starter, buggered the clutch safety switch and the ignition switch, discarded the whole fuel filter assembly, put a 'reconditioned' battery in that was worthless, and had done other ineffective butchering without resolving this simple underlying problem. After I spent a couple hundred dollars to get back to stock condition and do a major maintenance cycle including fresh fuel, it became the nice tractor that Yanmar intended. (Well except for the weathered paint!)

I'll go look at your other thread now.

About what I went through also. I ended up having alot of Electrical problems. Mostly just typical DA. from Neglect and Maint. and from plain just sitting Since who knows when? At least you had the US. problems to deal with just plain Lazy. I had alot VN. ghetto rig to deal with. I believe the previous owner at least just parked it and let it set. The good though everything else was in and in great Org. Condition. :thumbsup:

Hope your haveing a Good Xmas. Cal.

Carey

 

[Gary Sweat]

On a positive note, at least when you get everything fixed, you will know your tractor inside and out:thumbsup:

 

[284 International]

You're right, Gary, I will know it inside and out at this rate! It's nice to get something working again.