149 hydraulic implement lift sinking/dropping

[Maxwelhse]

Fixing the lift on my 149 has become the project from hell and now I need some help...

The bottom line is that the deck is dropping, while the tractor is running, from the desired height (as set by the lift handle) within about 30 seconds of positioning it. All new spiral pins are installed on the rockshaft and it goes up and down fine, hytran is full (maybe 75 hours on it w/CC brand filter), and tranny operates fine. It also isn't leaking anything.

The long version of events:

With questionable health (back problems) laying me up all winter, I went out this spring to replace broken spiral pins in the rock shaft as a "light, 2-3 hour project" just to get back to being somewhat active. I even bought nice stainless pins and a big bucket of copper anti-seize so they wouldn't rust up in there like the factory ones after 40 years.

I then found multiple previous owner "repairs" and issues (including bailing wiring 3 pieces of a broken pin into the shaft... unbelievable).. 10 hours and 1 slipped disc in my back later (could barely walk for 2 weeks), the tractor was back together. This required monstrous amounts of pounding things off of the shaft since the PO welded some holes round again, but didn't grind their welds worth a crap (or locate the new holes correctly, hence it can now be assembled wrong, AND the relief locations for punch access in the frame no longer line up), I ended up bending the "passenger" side lift arm pounding it off (had to take everything off due to the frame hole access issue). It wasn't that bad so I just straightened it out in the vice. After re-assembly, the 3rd time I hit the deck lift the lift arm broken and took the hydro cooling fan with it.

2 weeks later the gear carrier in my Jeep launched a few side gear teeth into the ring/pinion (fortunately happened at about 15mph)... Enter slipped disc #2 swapping another rear axle into my only driving vehicle.

Sooo.... Since I was legitimately barely able to walk for a good part of the summer, I had to back burner the tractor and ran it with no hydro fan and a busted lift (mowed the grass super short all the way down on the stop). I only mowed when I HAD to (maybe 5-6 hours all summer), left the tunnel cover off of for "some" ventilation, and did it on cool days (60s-70s). The metal lines coming out of the pump were certainly plenty hot when I would check them, but not hot enough to burn you instantly or anything (I'd guess 180-220F?).

Anyhow, if you're still with me after all of that, I FINALLY got the thing put together AGAIN (this is now like the 5th time since I had to discover all of the other gremlins along the way) with correct parts and a new hydro fan. Now the deck won't stay up. When I was messing with it yesterday ("final" repairs) the cylinder was sorta acting like it had air in it. If I pushed the control lever in the direction I was pushing the cylinder (to line things up) it would feel really springy and barely move. If I tried it again it would move immediately with almost no resistance.

Is it possible that the cylinder needs bled? I thought by design it was self bleeding? Is it also possible that I cooked an o-ring or something somewhere in the lift circuit by letting the fluid get too hot? Is the cylinder serviceable? I know I'm a bad cub owner for running it like that, but it is what it is at this point.

Also, I don't have pressure test equipment (and can't afford it, my health is just now getting to where I can even begin a job hunt) but I do have another complete hydro rear end (that was habitually run low on fluid for years and years to the point that it finally just quit moving the tractor entirely... again, thank a previous owner for that on) that I may be able to steal springs/trinkets from if I know where to steal them from.

Thanks for any suggestions you guys might have. At this point I may just get a goat... At least I could eat it if it pissed me off as much as this tractor has.

[Yosemite Sam]

So in a round about way, you're telling us that you laid around all summer watching television and eating Bonbons?

Sorry to hear about your troubles.

The cylinder could have an internal leak.

Can you set your lift stop to keep it from falling?

[olds45512]

its either a seal in the cylinder or in the spool valve, probably no way to know for sure which but id start with the cylinder because its the more common issue.

[64fleetside]

Check to make double sure none of your hoses/connections are leaking.
My local hydraulic cylinder guy rebuilt the cylinder on my 129. Chucks it up in a lathe to cut it apart, replaces the seals and then welds it back together.

[Maxwelhse]

Originally Posted by Yosemite Sam

So in a round about way, you're telling us that you laid around all summer watching television and eating Bonbons?

Sorry to hear about your troubles.

The cylinder could have an internal leak.

Can you set your lift stop to keep it from falling?

Ain't no round-about about it, that's fairly accurate. If it's on Amazon Prime streaming, I've watched it.

The lady's '93 Escort (she just finished law school and passed the bar exam to the tune of $117k of debt WITH scholarships and was rewarded for it with her first job as a lawyer earning less than a fast food assistant manager AND she's 150 miles away) lost its clutch @250k miles (and lost its body a long long time ago) and we were lucky enough to score rust free '95 Escort (same body, so now we have a parts car) with 80k on it in July for a sweet price, which is all she could pay.

Since then I've been easing back into the saddle by replacing ALL questionable parts of the car (inner/outer tie rods/ball joints, struts/mounts/springs, thermostat, fuel pump, water pump, timing belt, serp belt, plugs, wires, fluids, filters, hoses, brakes, swap good tires on, etc) in about 4-6 hour chunks while sitting on my rolling stool and with her help. Gotta give her credit; for a woman with no mechanical aptitude or desire to have any, AND a lawyer working on a beater car that she doesn't even like, she has troopered on nicely with handing me tools, cleaning gasket surfaces with a scraper/sand paper, and hanging out next to a fire extinguisher and a cell phone if an open tank full of gas should happen to ignite while I'm trapped in the back seat of a car that takes me 5 minutes to get in and out of...

So, now that Thunderscort #2 is up to snuff, and I'm much less crippled, it was time to face my old nemesis that started it all: the GD tractor!

Gotta start on the Jeep re-gear on the front to match the rear before snow flies too. Nothing is as dangerous on ice as a Wrangler in 2wd. 8 foot wheel base will get you in bad trouble fast.

Anyhow... I hope my bon-bon TV days are coming to an end. I've gotta start working (for money) again soon even if I drop dead on the first day. I appreciate the kind thoughts.

-----

Ok, back on my own topic. An internal leak in the cylinder, or maybe the control valve, was on my mind too. Any easy way to diagnose it or do I have to yank it off the tractor and try to bleed it down somehow?

And yes, it's set on the stop right now, and has been all summer, but it just cuts WAAAY too short like that. I can stuff a shim in there to prop it up to get me by, but if it can be fixed without much investment I'd rather do that. Plus I'd like the moral victory of actually fixing the damn thing that aided in crippling me for months.

Originally Posted by olds45512

its either a seal in the cylinder or in the spool valve, probably no way to know for sure which but id start with the cylinder because its the more common issue.

So the cylinder and valves are serviceable? Is that covered in any of the manuals? I googled and came up empty.

Originally Posted by 64fleetside

Check to make double sure none of your hoses/connections are leaking.
My local hydraulic cylinder guy rebuilt the cylinder on my 129. Chucks it up in a lathe to cut it apart, replaces the seals and then welds it back together.

100% sure they're good. Cleaned everything off well and parked on concrete for the last several months. No drips ( will continue to monitor though). Do you mind sharing who rebuilt your cylinder and what it cost?

[Maxwelhse]

Looks like the cylinder is non-serviceable, but the valve is, but the valve rebuild kit for the valve is NLA.

Do I just have to rip all of this stuff off and take it down to a hydraulics shop?

[ol'George]

IIRR all that is rebuild-able in spool is the "O" rings that keep it from leaking to the outside.
So that leaves the piston in the cylinder leaking.

[64fleetside]

My hydraulic shop put o-rings in my valve also but they are just usual hyd O-rings. I just gave all my stuff to him and let him handle it.
Gary Staples in Cabot, AR built mine, not sure what his normal $$ is, he did mine as a favor, I send him lots and lots of business as I built hydraulic hoses at my previous job.

[Maxwelhse]

My gut feeling is that an internal cylinder leak is probably the cause of the problem, but I can certainly change out a few O-rings in the shuttle on my own.

Does Gary Staples have a business contact of some sort or is he just a friend that helped you out? A quick Google didn't turn up anything and I sorta doubt my local shops are going to be equipped properly to cut the cylinder open, re-do it, and weld it back up... That seems sorta outside of the typical operation for the places I've been to.

Thanks for the suggestions/help.

[64fleetside]

he ships all over small one man operation Ill send his number in a PM.