Clemsonfor's Hydraulics rebuild.

[clemsonfor]

Inspired by Winston's Hydro oring replacement i decided to finially do mine. I have been thinking of doing it for over a year or more. When i bought the parts for my rear wheel seal, i bought the necessary orings for it as well. Since i had the tractor at the house i deceided to do it as well. I pulled the Hydro top off. It must weigh close to 80lbs!! It would have been way easier to pull the ROPS off to stand behind the tractor vs standing on top of the trator floor boards in reverse and manhandeling in upwards then resting it on the toolbox/ROPS then getting off and carrying over to a table.

Once off i took the back off the lift then took the front off the lift, then pressed the piston out with a long screwdriver. The front of cylinder was hard to get off. I think the o-ring on the cyl head kid of seized itself in or either the top seized to the main body. It took several good whacks with a chisel to the head then plenty of whacks of a deadblow hammer to get it to move, then i was able to pyr it off with a screwdriver and pull it the rest of the way out. But for you to pull the piston out the front you would have to do the same thing i did, but you could do it without removing the hydro top totally. BUT mine was not sealed well and was leaking so i wanted to remove it and seal it up good. This allowed me to kill 2 birds at once. I also put a new o ring under the 3pt control valve, and then put 2 on the holes that i guess control the fluid flow to the piston, that are under the cyl head.

Have yet to start the tractor up, as im waiting for the silicone to dry.

But again can i say i hate whatever the refurbers use to "glue" gaskets on!! You can barely scrape it with a razor blade. I resulted to a wire wheel to "wear" it away and "eat" it down to the metal. I mean the stuff is tough. They use some paper gasket stuff and some glue that looks greyish, but is not silicone like but kind of glue like i guess. It forms very good bonds in the joints, and the paper basically tears apart leaving some on each side.

Pics to follow.

 

[Gale Hawkins]

Thanks for all the detailed Photos and may it be strong when you test it.

 

[clemsonfor]

Im hoping so. Its a bear to wrassle that 80lb or so top out of there. I had my wife guide the hydro line in place thru the seat bracket as i was to lazy to take it off. If i do it again i will take it off. When you remove it its no big deal as itdont matter how you set it down, but with wet silicone on it you can just lay it down while you reposition it, you need 3 hands or an engine hoist or something.

And i try to take pics for those that like to see how its done. Helps eduacate those like me that like to see what there getting into before they actually do it. Job only may take an hour or so, except for the fact i spent half an hour cleaning gaskets off components!

 

[clemsonfor]

Winston kind of said this, but it is possible to get your piston out of a ym2000 without removing the whole top like i did. You can take the fron of the cyl head off and the rear and press it out. Mine would not do that though cause i had to do quite a bit of beating with a deadblow and finially a few hits on the edge of the caseing overhang with a chisel to free it up to remove it. I also had a leaky top seal to the trans that i wanted to fix.

Also i would of had to remove the ROPS to get at the back access cover but if would be possible to do it this way. If i did not have the ROPS and everything came apart it would be easy to do this in a half hour or so.

 

[clemsonfor]

OK filled the tractor up with fluid and tested it last night. It is more responsive it seems. It also holds better than it did but still slowly, slower than before, decends when tractor is off. So slow that i could not tell, but i went insided and 15 mins or so later came back out and it decended almost to the ground from about half way up i guess. (rough estimates on height and time though)

So this leaves the valve to be the problem i guess, i have not locked out the cyl yet though with the knob. I also took the vavle off and put a new o ring on the bottom, but did not open it up to clean and check the inside as it looked super sprung and i was woried about parts flying and also reassembly.

 

[Domush]

Just so you have a comparison, my three point can hold a box blade up for days without lowering more than an inch, maybe two. So there is definitely still something leaking. Did you replace the entire seal kit or just the o ring? Mine has an o ring as well as two nylon seals (one on each side of the o ring). This may be worn as well.

I'm interested to hear the result of closing the lockout. That will tell us a lot.

Sent from my SCH-I500 using TractorByNet

 

[clemsonfor]

The Ym2000 onlyhas 1 teflon ring behind the oring, not on either side, at least thats how Hoye shows it and mine was when i pulled it out. The ring looked word to me? But i got no clue how it should look. I did not purchase it as Winston said he thought it would be fine. But it did not look like an engine cyl ring that expands larger than the cyl diameter, it was just kind of there? I agree something is not right, but when i removed the filter for the Hydros the oring that seals the front chamber was rolled over in there, possibly allowing the unfiltered fluid into the system, possibly leaving trash in the 3pt vavle?? There was not much gunk on the filter so it was not very dirty or either not pulling much thru it???

 

[Domush]

Now that I think about it, I don't think closing the lockout will tell us anything, as it will simply create a vacuum if the piston leaks, making a few inches the most it will drop. If I recall the 3-pt layout correctly, the valve would simply act as a second piston, backing up the primary one. The same physics would happen if you tried to pull down on a tennis ball but had a vacuum cleaner sucking it from the top. It would want to move, but the vacuum would hold it in place.

If this is correct, then closing the valve will illuminate nothing and we're still at square one. The o-ring letting sludge past the filter is a logical next step. I fear you may be playing hide and seek with this issue until you get lucky. I know the piston o-ring on mine looked perfect, but a new one was a night and day difference in terms of performance (it wouldn't lift at all with the old o-ring, and can lift the front end off the ground afterwards). Though I still could not, by eye, tell the difference between the new and old o-ring.

Don't mean to be a black cloud, just trying to share my limited experience.

 

[clemsonfor]

Mine would still lift the front of my tractor off the ground. But even this new oring is better than old. I have had it locked out for an hour or 2 now, its not moved an ich it looks like. The old one would have dropped a few inches for 10 inches maybe by now.

According to Hoye if it passes the lock out test it means your vavle is the culprit, i see your point on the way you see it. I have not thought of it or paid attention to how the fliud enters it etc. So i cant comment on this theory.

My next step is to take apart the 3pt valve, but according to talking to hoye a year or so ago, there is not anything "rebuildable" in there. But there is a few orings i see in the diagram on the site. I will take it apart and try adn figure it out. Its nothing that stops me from using it, its just annoying as i am trying to do all these little things right now.

 

[Pete Judd]

I guess that I am lucky, the brush hog witch must be over 500 lbs, will drop maybe an inch overnight. I did this just to test, as I always lower the 3pt attachments to the ground. Don't want to get any of our critter under one, and have another one hit the lever. Might never happen, but also have the grandkids once and a while, and they like to climb on the tractor.

 

[clemsonfor]

Pette i lower mine as well, but its suppose to hold not drop. On the extreme end of this if it leaks to much casusing a constant flow of fluid through the vavle it will over heat the fluid causing you to loose lift ability and cycle time. I know cause my first vavle did that, the place i got the tractor from swapped valves and this one apparently has an ever so slight leak in it too??

 

[clemsonfor]

Been almost 24 hours and its not moved an inch since i locked the valve under the seat and left my boxblade lifted. The valve has to be bypassing somehow? Its either worn out or one of those orings is worn or there is trash in it?

 

[clemsonfor]

Three days with the Lockout closed and not budged a half inch!! It would never do that before. The trouble is definitly in the valve.

 

[clemsonfor]

Took the valve apart and put a new oring from Hoye in there. The old one was pretty worn and flat looking. The new one looks like its 2 sizes to small compared to the old one. Long story short the ball bearing and cup fell out upon dissasembly and i did not see how it went in, so the first 2x i put it in wrong, and it was way worse than the Original oring!! FOR those who DO THIS, THE CUP FACES THE BALL BEARING AND THE NIPPLE GOES IN THE SPRING! Those that take this appart will realize what im talking about!! I had the cup on the end of it all and that was the problem. Anyway the new oring is no better than the old one, it still leaks down about an inch and a half in 10 mins or so!! This is driving me crazy. I have had 2 guys to say not worry about it including one at Hoye. I have gone this far and it bugs me! Hoye said about half of them leak like that. I dont want mine too, but i guess i will have to live with it.

Also when looking at the Hoye diagram, there appears a snap ring that holds that plunger inthe inner cylinder, well on mine it was 2 cresent shape pieces of steel round wire. You have to depress the plunger and pic them out one at the time. There tedious at first but i think there better than a snap ring to get back in. Well maybe not, i could not use a snap ring as the one i ordered from Hoye was not close to fitting!

SO to summerize im no different that i was 2 weeks ago, except im an expert on rebuilding and dissasembly of the 3pt valve on a ym2000.

 

[winston1]

I hate to hear your results. Would you happen to have a picture of ref #3 on the control valve? I'll call that the piston, probably not the correct name. Just guessing a real close tolerance between it and the control valve body is what controls leakage. I sent you a pm.

 

[clemsonfor]

Maybe Winston, i figure thats what was leaking as that Piston thing had some rust on both ends of it some wear looking areas on the valve body.

Oh well, its perfectly fine, after all your implement is not really suppose to be in the air for days anyway, but that is how its designed, so i was trying to acheive these results.

 

[Doctor Bob]

Took the valve apart and put a new oring from Hoye in there. The old one was pretty worn and flat looking. The new one looks like its 2 sizes to small compared to the old one. Long story short the ball bearing and cup fell out upon dissasembly and i did not see how it went in, so the first 2x i put it in wrong, and it was way worse than the Original oring!! FOR those who DO THIS, THE CUP FACES THE BALL BEARING AND THE NIPPLE GOES IN THE SPRING! Those that take this appart will realize what im talking about!! I had the cup on the end of it all and that was the problem. Anyway the new oring is no better than the old one, it still leaks down about an inch and a half in 10 mins or so!! This is driving me crazy. I have had 2 guys to say not worry about it including one at Hoye. I have gone this far and it bugs me! Hoye said about half of them leak like that. I dont want mine too, but i guess i will have to live with it.

Also when looking at the Hoye diagram, there appears a snap ring that holds that plunger inthe inner cylinder, well on mine it was 2 cresent shape pieces of steel round wire. You have to depress the plunger and pic them out one at the time. There tedious at first but i think there better than a snap ring to get back in. Well maybe not, i could not use a snap ring as the one i ordered from Hoye was not close to fitting!

SO to summerize im no different that i was 2 weeks ago, except im an expert on rebuilding and dissasembly of the 3pt valve on a ym2000.

So I had an interesting situation occur with my 3 point hitch dropping with little to no weight on it. By the way, I use a hoe on the 3 point which has a wet kit on it driven by the PTO. With the hoe on the hitch it dropped almost immediately due to the high weight of the implement. So I really wanted the 3 pt fixed. Read this entire forum a number of times and felt reread to tackle the job.
Well after a wrestling match with the sheet metal and seat I got down to the3 pt box. First I pulled the rear 3 pt casting support of and no hole through the box to access the rear of the piston. Ok. So I pulled the front head off and it came off real easy. It was clean with little to no ridg at the top of the cylinder. Great news BUT no way to grab the piston and no way to push or drive it out because no access in the rear of the case. Well I jerked around for a bit and decided to go to the rear of the tractor and fully lift up an arm and drop it. BAM popped that baby right out. Piston was beautiful with no scores and yes, a brittle and broken seal. Here’s where it gets interesting.
The broken seal on the piston was a self energizing seal NOT an o ring and back-up Teflon ring. I had bought the self energizing seal from Hoye (parts guy is great and very helpful BUT seal was $50 plus $44 shipping. Wow. Seal number came out of my parts manual I bought with the tractor. It fit perfectly, was easy to install (flare was towards cyl head which made flare fold in when pushed into the cylinder) and I coated the seal and seal groove in piston with ATF assembly Lube. Worked great. wrestled the sheet metal and seat back in place and PERFECT FUNCTIONALLITY.
Heres the funny part. After reading this forum I went back to the Hoye diagrams and FOR MY TRACTOR (FX28D) they showed o rin and back-up Teflon ring. So I bought their piston seal set JUST IN CASE! $30. Didn’t need it. Maybe just maybe they did a change order and revised replacement recommendation from self energizing seal to o ring set up. Who knows? But I can honestly say tha I didn’t want to take the chance of tearing that dog down and not having the right parts. Turns out my parts manual was correct and it’s for sure that self energizing seal will do a much better job of handling heavy implements (like my hoe) than an o ring. SORRY FOR THE THESIS BUT I FOUND THIS TO BE PRETTY INTRESTING. Glad I bought that seal out of my parts manual. Really enjoyed reading this discussion. Well done by all and great technical detail. Bob in Texas