Help with a stuck 3 point lift

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Threeweight
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Help with a stuck 3 point lift

Postby Threeweight » Tue Jan 15, 2019 11:48 am

Howdy folks,

I purchased a YM 1500D with front end loader over the weekend. Tractor runs great, has a Coldwater loader that works great, 4wd, PTO, clutch all work great. However, it had been sitting for several years, and clearly had water in the hydraulic fluid. When I tested the 3 pt lift, it went up then got stuck, would not come back down. I made a lowball offer and brought it home, knowing I was getting a project.

I tore into it last night. Drained the hydraulic fluid (which was yellow with emulsified water), and pulled the hydraulic filter (which was gummed completely up with grayish goo, and had a tear in it).

While that was draining, I tried opening and closing the lockout valve, which did nothing to release pressure. I removed it and the housing (part #69 on this diagram - https://www.hoyetractor.com/CTGY/YM1500HYDLIFT.htm). It appeared to be dry behind it, with a bit of white corrosion on end of the valve stem. From there, I pulled off the three point valve, which appears to be in decent shape and fully functional. with some of the old icky hydro fluid in it... lift stayed up. I then pulled off the cover plate from the 3 pt piston and the cylinder it rides in... got a gush of nasty, gooey yellow and gray goop coming out, but the piston stayed in at the back of the cylinder and the lift remains stuck.

After I cleaned out the goo, I took a look at the cylinder walls and they appear to be in ok shape (at least the parts I can see). No pitting our rust. I sprayed the interior down with some penetrating oil, and tried whacking the 3 point arms with a hammer a few times to see if I could jar things loose, but no luck. So my guess is I have some kind of binding in the back of cylinder (since the arms went up when I tested it, i don't think it's the rock shaft).

I have a shop manual, new filter, and o-rings on order from Hoye. My plan is to remove the piston, polish it and the cylinder wall, then re-install with new o-rings. Anything else I should test first? Any advice on how to go about getting the piston out? Do I need to remove the entire lift housing? I've thought about removing the bracket on the back where the top link attaches, and then seeing if I can drive the piston forward with a wooden dowel and a hammer... this a reasonable thing to do before tearing things down further?

Also... my front end loader works great, and the pressure gauge on it shows I am getting pressure when I operate the lever to raise the 3 pt lift, so is it safe to assume my hydraulic pump is functional?

winston
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Re: Help with a stuck 3 point lift

Postby winston » Tue Jan 15, 2019 4:30 pm

Your pump is fine if loader works unless the loader has an auxiliary pump. Most don't.

Wouldn't be hard to remove #11. I wouldn't be afraid to whack the lift arms pretty hard but you still may have to remove 11 to get the piston out.
https://www.hoyetractor.com/CTGY/YM1500HYDLIFT.htm

Of course you will have to remove 21 to get the piston out.

Threeweight
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Re: Help with a stuck 3 point lift

Postby Threeweight » Tue Jan 15, 2019 6:49 pm

Thanks! #21 is off already (pulled it last night).

I grew up on a farm working on an old Ford 8n, but that was 30 years ago. Lift never seized on it, but I think my brothers and I fixed just about everything else on that tractor at least once. I have been a little leery of tearing in too far on this tractor without a shop manual.

This Yanmar 1500 is a red one, and cosmetically about a 7 out of 10. Still has a lot of the original Japanese labels on it. Hoping I can get her back in tip top shape, so I can put a bush hog on it and tackle the blackberry infestation on my property!

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Re: Help with a stuck 3 point lift

Postby Threeweight » Wed Jan 16, 2019 11:18 am

Two steps forward, one step back. I have more questions if anyone has suggestions!

Removed the back plate (#11) and found some weird rust on the rock shaft (#44) and inside the top of the hydraulic housing itself (#3). It looks almost like mineral scale/rust combo, like vapor condensed here (maybe the highest point inside the tractor?) and left behind a nasty rusty crust. This led me to pull the whole hydraulic housing off. It's kind of weird because there are little bubbles of this nasty stuff, and the surrounding metal is in perfect shape.

So the good news is the transmission and PTO look great... some sludge in the bottom as expected, but with it open I am planning to spray things down with carb cleaner then siphon what won't drain out with a oil suction pump I have. The hydraulic shaft looks fine, as does the arm that actuates it on the rock shaft. The bore of the cylinder that I can see looks fine, but the piston is locked up tight in the back of it. The nasty part is this scale is really bad on the splines of the rock shaft... I soaked everything in penetrating oil, and I was able to get the lift arms and rock shaft moving (as far as I can with the piston stuck at least), but now I have a new problem.

There is not enough room to get the roll pin out that holds the piston shaft (#16) in the cup of the arm of the rock shaft (#43). I don't think I have enough room to drive the hydraulic piston out of the cylinder without the hydraulic shift being removed. So it looks like I need to take the rocker shaft out first. The problem is that scale is an 1/8" of an inch thick in places, and I can only access the bottom 2/3 of the splines.

Any advice on how to remove that scale? I am going back and forth between trying to soda blast it, soak it in an acid based rust stripper, or try to get as much as I can with a wire brush on Dremel. Any suggestions?

winston
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Re: Help with a stuck 3 point lift

Postby winston » Wed Jan 16, 2019 6:50 pm

I am not there so can't be for sure about anything. If you are able to move the piston any at all it should free up and come out the front without much persuasion. I would avoid taking the rockshaft out if it can be avoided. If rock shaft is free you should be able to push the piston from back and with front removed you should have access to move the piston back. Just keep working back and forth till it frees up.

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Re: Help with a stuck 3 point lift

Postby Threeweight » Thu Jan 17, 2019 12:13 pm

Piston hasn't budged yet, I just got the lift arms and rocker shaft to move about 1" back and forth (still very very stiff). That's as far as it can go without the piston moving.

I flipped the whole housing upside down last night, capped the vent tube, and filled it with Evap-o-Rust. Letting that liquid sit for 24 hours to soften up that old nasty scale and rust, then I'll clean it out and start again with the penetrating oil tonight.

Is there any special trick other than elbow grease for getting the 40 year old paper and adhesive gaskets off things? I tried a razor scraper, hard plastic scrapers, and soaking them in WD40 last night, but that stuff is tenacious.

winston
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Re: Help with a stuck 3 point lift

Postby winston » Thu Jan 17, 2019 2:54 pm

A cheap air scraper like this works pretty good. https://www.harborfreight.com/6-piece-p ... 95826.html

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Re: Help with a stuck 3 point lift

Postby Norm » Thu Jan 17, 2019 7:22 pm

A scraper, (not plastic), dipped in ACETONE usually works well on most all adhesives.

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Re: Help with a stuck 3 point lift

Postby Threeweight » Fri Jan 18, 2019 12:36 pm

The Evap-o-Rust bath broke down a bunch of the crud. Between that and some scrubbing with a small stainless brush, the housing and rocker shaft is looking a lot better. Unfortunately, the piston is still seized up tight. It's on my work bench soaking in penetrating oil again now, going to pick up a bigger hammer and try to persuade it again tonight. If that fails, I guess I'll try some heat next.

Didn't have a can of liquid acetone in the shop, so I tried a little carb cleaner on the old gasket material... it does the trick!

Threeweight
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Re: Help with a stuck 3 point lift

Postby Threeweight » Tue Jan 22, 2019 1:29 pm

Soaking in penetrating oil and some persuasion from a 4# hammer finally broke the piston loose. There was some crud build up around the tail end of it, which caused it to bind in the cylinder.

New issue is the rocker shaft was also super tight, like some crud or something was built up in the bushings. I was only able to get the lift arm off one side so I could pull the O-ring and get oil in there, but the other arm is stuck tight. Have been spraying and soaking what I can reach with penetrating oil as best I can, and working back and forth (first with a cheater bar, now they will move by hand but still really stiff).

Anyone know how much resistance the lift bars and rocker shaft are supposed to have? Should it be tight (takes two hands to rotate up-down tight) or loose (rotates up and down smoothly with little resistance)?

winston
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Re: Help with a stuck 3 point lift

Postby winston » Tue Jan 22, 2019 1:54 pm

Should fall down with it's own weight.

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Re: Help with a stuck 3 point lift

Postby Threeweight » Sun Jan 27, 2019 11:12 pm

Continuing the theme of 2 steps forward, one step back... finally had time over the weekend to get back to the tractor. Got the rock shaft lubed and functioning well again, got the hydraulic cylinder and piston cleaned up, new O-ring on it, and proceeded to re-assemble everything (with new gaskets). Once I got everything back on the tractor, I put in a new hydraulic screen and filled the transmission with new hydraulic fluid.

Started the tractor and... hydraulics are dead. No 3 pt lift, no front end loader. Turned it off, then started troubleshooting. I loosened the fitting at for the big hydro line to the top of the 3 pt valve, and tried cranking the tractor over (with no throttle, so it can't start). I got a big gush of nasty yellow fluid (assuming this is coming out of the lines). I take this to mean my pump is fine, and my problem is likely in the 3 pt valve.

Ran out of time to mess with it this evening, will take it up again tomorrow. My only other thought was maybe I had air in the system, but from what I understand the hydraulics should self-prime with the engine running?

winston
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Re: Help with a stuck 3 point lift

Postby winston » Mon Jan 28, 2019 5:10 am

Filled with transmission/hydraulic fluid, right? Not hydraulic fluid? I am assuming your flow goes through the loader and then onto the 3 point lift. If neither loader or 3 point is working then you have a pump flow problem. Possibly an air lock. Might try loosening a fitting on the pump outlet line closest to the pump and cranking it over. It is self bleeding but might need a little help.

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Re: Help with a stuck 3 point lift

Postby Threeweight » Mon Jan 28, 2019 11:11 am

YM 1500D, the transmission and hydraulics share a common sump. Hoye recommends a JD 303 fluid for it, so that's what went in (Coastal Farm and Ranch's higher end house brand, JD 303 and J20 specs.)

I will try cracking a fitting tonight and cranking it over until I get clean fluid out. Doing the lower fitting you suggest over an oil drain pan is a much better idea than painting the tractor nasty old fluid from that top one (like I did last night!)

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Re: Help with a stuck 3 point lift

Postby Threeweight » Tue Jan 29, 2019 9:57 pm

Wanted to check back in and say thanks to Winston and others who offered advice!

Bled some fluid/air from the system using one of the lines feeding my 3 point tonight, then fired the little tractor up and success! FEL working great! Had a momentary scare when my 3 pt went up but wouldn't go back down again, until I checked and realized I had left the stop valve under the seat shut. Corrected that, now everything works!

Still have a few other projects to tackle. I already changed the air and fuel filters, needs an oil change and new gear lube in the front axle and steering box, and I need to install the rear wheel spacers I got from Hoye, straighten the bent steering rod, then he should be ready to go to work!


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