820 3pt drifting down

[tboycat]

just got a 70 model 820, nice clean little tractor, but noticed when sitting, idleing, with attatchment on it,it will slowly drift down ,,then all of a sudden it will jerk back up to where it was, i turned the lever under the seat that adjusts how fast 3pt comes down but it had no affect on the drifting problem. could this be from dirty filter or clogged up screen ?or maybe relief valve? thanks

 

[davesl708]

Hi. Welcome.

The control valve may be dirty or damaged from over tightening.
First thing I do when getting a new used machine is change all the fluids. If exceptionally dirty fluid I flush cheap fluid through the system to clean it out then put in the good stuff.

How many hours on the machine? Any ideal how it had been used?

 

[tboycat]

Hi. Welcome.

The control valve may be dirty or damaged from over tightening.
First thing I do when getting a new used machine is change all the fluids. If exceptionally dirty fluid I flush cheap fluid through the system to clean it out then put in the good stuff.

How many hours on the machine? Any ideal how it had been used?

the meter shows around 9000, it was used for bush hogging and discing on a small farm. im pretty sure fliuid needs changing, its first on my list. i was just concerned about the way it jerks back up. it drifts down real slow,then all of a sudden it just jerks back up to the level u had it set to begin with

 

[beenthere]

There is a tran filter and as well looks like a transmission screen.. shown here in schematic as item 34

 

[retro7570]

Worked on a 3000 Ford last fall,doing the same thing. Turned out the packing was bad on the lift piston.

 

[jenkinsph]

just got a 70 model 820, nice clean little tractor, but noticed when sitting, idleing, with attatchment on it,it will slowly drift down ,,then all of a sudden it will jerk back up to where it was, i turned the lever under the seat that adjusts how fast 3pt comes down but it had no affect on the drifting problem. could this be from dirty filter or clogged up screen ?or maybe relief valve? thanks

I would suspect the rockshaft cylinder is leaking fluid past it. The position control is raising it back up and working as it should. Screwing in the ROD control (rate of drop) under your seat should shut down the flow of oil and not allow the hitch to drop. Since this did not affect the drift it indicates the cylinder itself is at fault.

I had an 820 for 16 years and it was a good tractor.

 

[Tx Jim]

Ditto what jenkinsph stated. With 3 pt fully raised,engine running look in hyd filler hole behind seat for dribbling oil. Dribbling oil could be faulty 3 pt piston seal &/or faulty 3 pt control valve seals(parts keys 20,22 & 23).

 

[MF283]

I had an 820 for many years, great tractor, somewhere amongst all my clutter i have a IT manual for it, i'll try to find it if you want it.

Ronnie

 

[jenkinsph]

just my thoughts but I would check the hydraulic fluid for water (milky) and if it is okay I would hold off on changing it. I would clean everything up real well and then run the tractor and see if you have leaks to deal with. You may need to fix a few things which would entail draining the oil before refiling with fresh fluid.

The drift if minor could wait too, heck a lot of new tractors drift down. That repair is higher than the fluid so it could be done after the fluid is changed. Look at the shifter boots, if they are cracked this will allow water to get in the transmission. Look at the hitch arms on each side where the attach to the load and depth control on the lower housing and see if these are leaking. Just some of the things to look for before changing the fluid.

 

[Zebrafive]

just my thoughts but I would check the hydraulic fluid for water (milky) and if it is okay I would hold off on changing it. I would clean everything up real well and then run the tractor and see if you have leaks to deal with. You may need to fix a few things which would entail draining the oil before refiling with fresh fluid.

The drift if minor could wait too, heck a lot of new tractors drift down. That repair is higher than the fluid so it could be done after the fluid is changed. Look at the shifter boots, if they are cracked this will allow water to get in the transmission. Look at the hitch arms on each side where the attach to the load and depth control on the lower housing and see if these are leaking. Just some of the things to look for before changing the fluid.

Agree, bad shifter boots are a know source of water entry. Fix ASAP if bad.