2-105 hydraulic

[rrlund]

Well...I mentioned below that I put a rebuilt pump on my 2-105 last week because the hydraulics were overheating. I cut hay this morning and after an hour, the light started blinking again. I let it cool off and went back after dinner. I went about 40 minutes this time. There's a Mennonite hydraulic shop a few miles away. I went over there and he said he'd come over tomorrow at 1 and take a look at it. There seems to be a pin hole in the suction hose between the filter and pump. He didn't have any inch and a quarter, so he told me to put a piece of inner tube and some clamps on it and try that. Didn't help. Don't just assume it's the pump if overheats is the lesson here. I'll let you know what he finds.

 

[tom upton]

I have had three occasions now where guys had bought a new pump and the compensator was set higher than the main relief, and for whatever reason mechanic didnt know he had to set compensator, or maybe didnt even know how? One was a Agco dealer. The other issue I have seen is crap from the old pump that was indeed bad had gotten in to the main relief body holding relief open. As you probably know the prerequisite to installing a new pump nessitates cleaning out the valve bodys as pump flow goes directly there with no high pressure filter. Unlike most industrial applications of the same basic pump utilize a high pressure filter. When you think about it a fella should probably look at how hard it would be to plumb in a high pressure filter??

 

[rrlund]

I have had three occasions now where guys had bought a new pump and the compensator was set higher than the main relief, and for whatever reason mechanic didnt know he had to set compensator, or maybe didnt even know how? One was a Agco dealer. The other issue I have seen is crap from the old pump that was indeed bad had gotten in to the main relief body holding relief open. As you probably know the prerequisite to installing a new pump nessitates cleaning out the valve bodys as pump flow goes directly there with no high pressure filter. Unlike most industrial applications of the same basic pump utilize a high pressure filter. When you think about it a fella should probably look at how hard it would be to plumb in a high pressure filter??

Thanks Tom. I'll pass all of this along when he gets here tomorrow.

 

[rrlund]

Well.....here's what happened so far. He backed the compensator out one turn. I thought a had a good test gauge set, but it wasn't as good as I thought. He took a plug out of the relief valve and hooked the hose and gauge up. I started the tractor and it blew the end right off the hose. It soaked him an his clothes, but didn't break the skin. He picked the gauge up off the ground and said "Look at that. Pegged at 4000 pounds."

So now we didn't have a gauge, but he took all three relief valves out of the castings and they looked good. He backed the compensator out two more turns and I drove it to his place. The brakes and steering worked good, the pump was a lot quieter, but there wasn't enough pressure to even lower the 3pt or make the remotes make any sound when I held the levers. I had let it run while I unhooked the haybine, then drove it to his place and I'm not going to tell you the pump was stone cold, but I had no problem holding my hand on it. I'd say warm, but not super hot like it would get in ten minutes before.

I think we're on the right track with the compensator, he just needs to get it dialed in.

 

[tom upton]

Well.....here's what happened so far. He backed the compensator out one turn. I thought a had a good test gauge set, but it wasn't as good as I thought. He took a plug out of the relief valve and hooked the hose and gauge up. I started the tractor and it blew the end right off the hose. It soaked him an his clothes, but didn't break the skin. He picked the gauge up off the ground and said "Look at that. Pegged at 4000 pounds."

So now we didn't have a gauge, but he took all three relief valves out of the castings and they looked good. He backed the compensator out two more turns and I drove it to his place. The brakes and steering worked good, the pump was a lot quieter, but there wasn't enough pressure to even lower the 3pt or make the remotes make any sound when I held the levers. I had let it run while I unhooked the haybine, then drove it to his place and I'm not going to tell you the pump was stone cold, but I had no problem holding my hand on it. I'd say warm, but not super hot like it would get in ten minutes before.

I think we're on the right track with the compensator, he just needs to get it dialed in.

To set compensator I Just use a 3000 pound guage plugged in to a remote. Pull lever to engage that remote. Assuming it is backed out too far now have someone you trust turn compensator in/clockwise slowly while you watch the guage. Note: once it starts increasing it does not take much turning of compensator to increase pressure. When compensator reaches relief pressure setting, turning it farther will no longer increase pressure, as it will now be going over main relief at whatever the fixed shims have it set at. Make mental note of psi that guage quit increasing. Release remote lever until guage reads 0 . Back compensator off a couple of full turns. Engage remote lever again and increase compensator to at least 10 percent LESS than pressure it was blowing over the relief. 15 is better if you still have ample pressure to run things. My 2-105 is only set at 1850 and it runs everything fine.
If relief is blowing over at a less than a couple thousand PSI I guess you are going to need some shims.
Not sure what guage port there is on main relief that he could have used, but sounds like it was before the relief not after??

 

[DanielW]

The relief on our both 105 and a few friends/neighbours 85's and 105's I know of all had the relief shims hammered out over time to the point the relief pressure was less than the compensator de-stroke pressure. A few more shims were needed to bring the relief pressure up to an acceptable range. Definitely worth looking at and setting as per Tom's notes above. Because I don't need a lot of pressure on ours I set the compensator to de-stroke at about 1300 psi, and the relief at about 2100. That's a lot more difference than you'd typically have between compensator and relief, but I wanted to keep it low because I'm getting more bypass in my pump than it should have, and the lower pressure will keep it cooler and hopefully add some longevity. I don't really need it higher for anything we use the tractor for. But if I ever need more pressure, I can turn it up to 1800 or so without worrying about going over the relief.

If (as I suspect) your relief shims are hammered out and it's relieving at too low of a pressure, these are the shims you'll need (#21 in pic below). I made my own from shim-stock, but I'm sure they're available from Agco as well. While you're in there, I'd pull out the relief seat (#25) and replace the o-ring on it (#24). Don't lose the ball (#26) when you pull it apart. In my case the o-ring was also a little perished and showed some signs of letting fluid bypass. The Agco parts books are nice because they give the o-ring sizes, so you can cross-reference to whatever standard SAE sizes they are an pick them up at your local NAPA or from any standard o-ring kit. O-ring part #24 below has 1/16" nominal cross-section by 5/8" nominal I.D., which is an SAE #16 o-ring. O-ring part #22 below is an SAE #124 o-ring.

The seat (part #25) was a real pain to get out on mine, because the o-ring was perished and had mushed its way around the outside of the seat and stuck it in the bore pretty solidly. If I remember right, there are internal threads in the seat you can thread a bolt/machine-screw in right in the middle of the ball seat and pull it out. Be careful not to mar the machined cavity the ball sits into when doing this. In my case, I didn't have a machine screw with the right size threads handy, so I did it a bit more crudely: Once I had the cap, spring, shims, plunger, and ball removed I held a bucket in front of it while my brother fired up the tractor for a second, and it shot the seat into the waiting bucket. Probably not a recommended practice, but it worked for me.

When reassembling, it's a bit of a pain to get that ball (#26) centred and held in-place as you install the plunger (#27). I just used a gob of thick grease to hold it in-place on the plunger while I assembled. This all can be done on the tractor without removing the valve assembly, but you want to make sure everything's uber clean before and while doing the reassembly. And best to work over a concrete pad (or at least a tarp) to catch any pieces you might drop.

 

[rrlund]

I called him this morning and told him how Tom said to set it. He was greatful since he wasn't sure what the relief pressure was set at. He said he'd call when he got it set.