1986 Ford 1210 - 3PH pulses up/down slightly with heavy load

[jgayman]

My brother has a 1986 Ford 1210. Recently it has developed an issue where the 3PH pulses up/down slightly when there is a heavy load attached like a 6ft rear blade. It is most noticeable when the hitch is raised to the half-way point. It will sit there and continue to raise and lower by about an inch or so. It does not exhibit this condition when the hitch is raise all the way or lowered all the way. It also has to have a certain about of weight on the hitch to do it. The 250+ lb. rear blade will do it but a 200lb person on the hitch will not.

Any ideas?

The oil looks clean on the dip stick and is at the proper level. It's been almost 200 hrs since the hydraulic fluid and filters have been changed.

I would also be interested if anyone knows the details on the hydraulic filters on this tractor. Looking at the parts listing it appears to have three filters. A main spin-on filter on the left side of the engine, a filter cartridge inside a bullet-shaped silver housing on top the hydraulic pump, and a suction screen filter located on the left side of the rear axle housing, just inside the rear tire.

Also, the loader operation on this tractor seems very strange. For the loader to operate correctly, the rockshaft lever needs to be at the half-way position. There is even a little metal guide showing you where to position the lever. If the lever is not at this position the loader will raise no matter which way you push the SCV. I'm sure this is normal but does anyone know why it works like this?



I've include photos of the filters below.

 

[rayikeo2]

When my 1700 did the same thing it was because the 3 pt lift piston seal was leaking and needed to be replaced. What happens is when the lift goes up, some of the fluid leaks around the seal and it loses pressure and drops the arms. Then the pump immediately pumps more fluid to the piston to lift it back up. It's a continuous process when the seal leaks. If that is the problem, if you shut off the tractor with the lift up, it will leak down by itself, faster if loaded with the blade. The repair can be done bu the owner if he is mechanical.

The filter and loader problems, I can't help you with.

 

[jgayman]

I thought about the lift seal but if the tractor is parked with the 3PH raised with the plow attached it stays raised for a couple days before lowering.

 

[KYErik]

Perhaps the bore of the lift cylinder has a scratched/worn area at about the halfway point that allows fluid to leak by only when the piston is in contact with the scratched area. Have him raise the plow to the halfway point (where it pulses) and then shut the tractor off and see if it stays or drops.

It may not leak down when the plow is raised all the way at the highest point because that part of the cylinder bore is smooth and sealing correctly.

 

[jgayman]

Thanks... will give that a try.

 

[rayikeo2]

Your seal is leaking at the early stages. It will get worse with time. If the 3 pt drops in 2 days, it will soon change to 1 day, then overnight and finally 2 minutes. The reason it shows more when a heavy implement is on the lift is because there is more weight that it has to hold up. This puts more pressure on the seal. It will get worse and hold less as it it leaks more as it continues to wear out.
Replace the seal before you look for any other problem with the lift.

If the seal is good, the plow will stay up forever, it will not drop in 2 days.

 

[jgayman]

Thank you for the replies. I'll have to do a test again but I know with the engine shut off it stays up at least a day. I seem to recall that he also said if he closes the drop-rate knob all the way after the implement is raised that it will stay up for like a week. As for staying up forever... even my new Deere 2720 does not stay up forever. With the rear blade on it will bleed down in a few days.

 

[sld]

I've had some pretty heavy stuff on the back of my 1210 and it did the same thing. One thing that helps is to slow down the flow rate with the black knob under and in front of the seat.

 

[bspeedy]

As others have said, it's the lift seal. My 1700 was fixed with 50 bucks in parts and 20 minutes of work. Took longer to get the tools together. Good luck.

 

[jgayman]

Thank you for the suggestions. One other question... this tractor has a front-end loader (Amerequip 64Q) which is attached to the hydraulic manifold block on the right side of the tractor. According to the manual, this block has a control screw which you turn to select "lift linkage operation" or "hydraulic equipment operation". What does that mean? Does that mean I need to chose between operating the 3-point hitch or the loader?