Rear Lift won't drop

[deepNdirt]

Hello all,
I think I have read someone else having this sort of issue as well, although not sure how far back in threads I'd have to go to find the answer?
So I hope Y'all don't mind me asking it again............ today while plowing my garden the tractor and all hydraulics working Great, when I finished plowing I pass by a Pompass grass plant on the way to park my tractor, I thought how fed up I get by having to cut grass around this thing, so I dug it up with the FEL took it to the back of our lot lift it over the 4 ft fence and dumped it on the other side to dispose of the evidenced, the wife will be asking me what happen to it?
anyway on to park the tractor let the FEL down and then the rear but the rear 3 pt hitch would not drop, actually it was way up higher than usual almost hitting the back of my seat, I went ahead and shut off the tractor thought perhaps it would go ahead and drop? Nope! I re-started it and work the FEL and all work just fine with the loader hydraulics and again the rear wouldn't do anything, however I did notice that while working the FEL it was helping to release pressure to the rear but by very little, it started down slowly about 2 inches in 5 minutes, but once I started back with operating the FEL the rear would climb back up on its own, all the while the rear 3 pt lift lever is all the way down, I of course fooled with this lever but had no effect what so ever on the lift, I also turned in and out on the knob under the seat and no change, looks like I'm stuck with the set of Harrows up in the air on my tractor untill I can be advised as to what the problem is :confused3: ????Please???? :anyone: and Oh! BTW its My YM 1700

 

[Hooked_on_HP]

I know nothing about Yanmars but I will try helping. Is there any linkage going from the TPH lever to the rocker box? My ford has a rod that goes from th lift arms to the control valve to control how far the arms lift.
Bill

 

[deepNdirt]

yes there is a couple of linkages that run over to the 3 ph valve, that looks like would actuate a small plunger valve of some sort, as I lift the lever the arm that would be pushing this plunger in backs off from it and does not touch at all, although I cannot see this this plunger come out as the arm moves away, nore can I see it push in as I let the lever move to the lowering position,
should this part ( Plunger)be moving in and out as the lever and arm pushes against it? I mean it does seem as though this must control something having to do with the lift and Hydraulics,
Thanks

 

[mmurphy]

That will teach you for messing with the wife's Pompass grass! I think you have met karma! I have to say the same as Hooked on hp, and I just could not pass that up.

 

[deepNdirt]

That will teach you for messing with the wife's Pompass grass! I think you have met karma! I have to say the same as Hooked on hp, and I just could not pass that up.

Ha! well if it will put my tractor back as it was, I'll go re-plant the darn thing

actually the reason I mentioned the Pompass grass was because when I lift the FEL to the height to reach over the 4 ft. fence..... thought perhaps maybe this might have had something to do with it? actually this morning I removed the return line from the reservoir so I could check the Hydraulic fluid level, and it just does touch the tip of the dipstick, perhaps when lifting the bucket so high it pulled the Hydraulic level down to far for the rockbox to work properly?
I'll be getting some Hydraulic oil today and ad to it to see if this might be the problem

 

[Diamondpilot]

I would not add fluid just yet. 3 points are gravity down/power up and when you lower the lift the level will probably be just right by the fluid returning from the lift side of the 3 point cylinder. More than likely what has happened is some adjustment got moved and it over lifted and pushed the lift piston out of the cylinder. More than likely you will have to remove the seat, open the lift box and put it back in place. When this happens it usually tears the seals so they will also need replaced.

Chris

 

[deepNdirt]

I would not add fluid just yet. 3 points are gravity down/power up and when you lower the lift the level will probably be just right by the fluid returning from the lift side of the 3 point cylinder. More than likely what has happened is some adjustment got moved and it over lifted and pushed the lift piston out of the cylinder. More than likely you will have to remove the seat, open the lift box and put it back in place. When this happens it usually tears the seals so they will also need replaced.

Chris

OK rear lift has now gone down after removing the 4 bolts and banjo fitting & line the Assembly was stuck on so I turned around to grab a hammer and pc of woodruff to tap with and all the sudden blam! Old Faithful has sprung in my shop the 500 lbs worth of harrows slam to the ground and my nice new painted Yanny just got a bath with Hydraulic fluid, Oh! BTW does anyone know what Hydraulic fluid will do to paint?:ashamed: and it was all over the ceiling I thought about how much of it could had been on me if it had given way while I was standing over it:confused2:no doubt the good Lord was looking over me, I could have also been hit with that part............... anyway! now that thats done and the lift is down I move on to the examine the part that wound up 3 foot from the tractor, all seem OK on outside :thumbsup: But I'm guessing the inside is the culprit to the problem the small plunger I had mention now seems to be working fine in and out freely, there are some orifices all along the inside of this part so I will be checking for any obstructions and trying to force air through them, anyone know of any reason I should not use force air on this part ?

 

[Hooked_on_HP]

Hyd pressure is a lot higher than air pressure so blow away.
Bill

 

[deepNdirt]

while trying to disassemble the valve I found that the piston was not moving freely, it was stuck in place I kept pushing it one way and then back the other until it felt free enough to push on thru, when I got the pistion out I found that the plunger inside was stuck I could pull back on it with plyers but then pushing it back in was dificult, I nottice the spring inside was not pushing back the plunger like it should, after pulling it back again several times I see something comeing from around the plunger, Looks like what was supposed to be a C-clip broken in 2 pc, I think this was the culprit to the problem, What I need to know is this in fact a C-clip? and now that these broken pc's are out shouldn't thie plunger come on out as well?
Thanks

 

[deepNdirt]

Does anyone know where I can get the schematic breakdown on this assembly? I put it all back together and it worked for 3 lift & down cycles, and even though it does not stick in up position now it will not go up like it's supposed to, it does however make effort to try, I mean the lift arms come up until the load of the implement and goes no further, I have press a flat screw driver in between the push arm of the lever and the plunger and can get it to come part the way up, although the lever feels like has heavy pressure on it and down not stay in position,......... so I'm off to removing this assembly once again, and would be grateful to get the schematic on this part,
Thanks