Rock Shaft/3 pt hitch rate of drop control, 3000/4000

[Red Horse]

The valve controlling the rate of drop for the 3 pt. hitch on my 4720 has always been very difficult-I should say more like frozen when I bought the tractor with a little over 200hours. I finally decided to see if I could free it up and I discovered there is a big packing nut on the control shaft where it goes into the housing. I backed off on that and it seems the rod is frozen to that nut. I shot some WD40 on it but no luck.

Anyone have a similar experience?
Appreciate any opinions.

By the way- it is frozen in a "fast drop" position

 

[kennyd]

I'd try a real penetrate/lubricant and shelve the WD(water displacement)40. Fluid film and PB Blaster are my go-to's. If that doesn't work I'd remove the assembly and find the corroded part and replace or polish it.

 

[Red Horse]

I'd try a real penetrate/lubricant and shelve the WD(water displacement)40. Fluid film and PB Blaster are my go-to's. If that doesn't work I'd remove the assembly and find the corroded part and replace or polish it.


View attachment 443169

Thx Kenny. I'll get some PB and give it a shot-no pun! I had looked at that schematic and I'm hesitant to pull the shaft out as given the fact its a cab, I can see myself having to pull a rear wheel to get at this thing
Bob

 

[brown40]

On an open station you'd remove the seat pan and it'd be right there; does the cab bottom cover that access? Power beyond plumbs in around there, so I'd think the engineers would want to save the service folks the hassle... of course I've been shocked by other manufacturers poor planning/lack of foresight for future issues.