John Deere 870 3 point hitch hard to lower

[tpar]

Hello, I am new to this forum and this is my first post. I have a JD 870 which I've owned for 20 years with only 476 hours. I only use it to occasionally shred or finish mow and at times use an auger to dig post holes.

Recently I discovered the 3 pt will not lower unless my shredder is mounted. However, when nothing is mounted, I have to stand on the draw bars and jump on them to force them down. I have the shop manual and have disassembled the cylinder cover and rate of drop valve to clean them. The drop valve was perfectly clean and seemed to function properly. (I could move it back and forth in its cylinder.)
I observed that the rockshaft arms still did not fall down with the cylinder cover removed. I stood on them and jumped and had a helper watch the piston move towards the top of the cylinder. In the manual it states "to remove the piston, manually lift the rocker arms them jerk them downward to thrust the piston rod which will pop the piston out.." In my case, I can not manually lift the arms up, and was only able to jump on them downward.

Sounds like I need to remove the entire rockshaft housing and clean/inspect. Or is there something I can try without doing that? Any ideas what is binding the rockshaft? Is it true that I should be able to raise the arms manually with the tractor not running the hydraulic pump?

Thanks for your help.

 

[tpar]

In looking at the diagram, I'm wondering if the problem is rust in between the lift arm splined sleeve and the bushing on one or both sides. I say this because, when running the tractor and lifting the shredder, it is not smooth. It is a bit jerky to raise the implement. Then to lower, I have to have a load or if unloaded jump on the arms to lower. My point is, the arms will lift and lower, but with help. Does this sound like binding on the rockshaft/sleeves/busings? Or am I looking at a relief value or the rockshaft valve. I'm trying to avoid removing the entire housing. Maybe I can remove the lift arms and spray penetrating oil in there? I'm not sure..

 

[tpar]

Problem Solved. Sure enough, there was rust between the lift arm sleeve and the housing bushing on each side just enough to make it difficult to freely rotate and bring the arms up and down. I shot some penetrating oil at the edge near the housing without removing the arms. I used a floor jack to lift the arms, then shot some more oil. From that point I was able to lower the arms and raise them with no assistance. I did this several times to free the arms. I'll reinstall the cylinder housing and drop valve in the next couple days then try things out. Should be good.

Just wanted to post this fix. Definitely caused by my tractor doing more sitting than working!

If anyone needs guidance removing the drop rate valve and cylinder housing, let me know. I have some experience now.

 

[JimRB]

My 870 has been sitting outside since it hit the states probably 22 years ago. Not many hours on mine either. Maybe 800. Never had an issue with things not going down in back. Good to know you planted a seed of information in my mind.

I do have some squeeks with the clutch. Some of the pivots have no grease or oil ports. It looks like the only way to lube is to split the tractor. No room in the too small garage for that so it will continue to squeek every so often.

 

[tpar]

JimRB, mine has spent most of the time sitting in a garage. However, the past several years it has been parked outside. I'll be clearing out space to put it back. The only other problem I've had was the clutch would stick to the pressure plate from sitting too long. I think some surface rust would develop. To fix it, I found a small access plate on the bell housing that I could remove and use a hammer and wood or metal rod to hit the clutch to separate. Fairly common problem. To solve the problem, I now use a piece of wood 2x4 to hold the clutch pedal down when storing the tractor. By the way, I live near the gulf coast and we have high humidity down here.

You might be able to put some oil on the sqeek via that access hole. Just be sure to go easy and do not getting any on the clutch surfaces.

 

[bigdeano]

Seems like they should have put grease fittings on those rock shaft bearings. Guess you'll just have to squirt some oil on them once in a while.

 

[tpar]

Seems like they should have put grease fittings on those rock shaft bearings. Guess you'll just have to squirt some oil on them once in a while.

Yeah, a little oil and moving them more frequently should do the trick. All the problems I've ever encountered is from lack of use. I need to use the tractor more! And now that I'm semi-retired from my day job, I'll get to do exactly that.