60 Rockshaft Frustraited

I worked on my 60 over the weekend trying to fix the falling rockshaft problem. The rockshaft will lift, but it wont stay up. I have fixed this in 2011 by adding a new o-ring and leather on the internal piston (going from the back of the tractor not removing the rockshaft housing). This failed last fall so I fixed it again last fall. Now it failed in June. So this time I felt around in the cylinder and found one spot where my fingernail would hit a rough spot. The o-ring and leather looked Ok on the piston, with one spot perhaps a little wore on the rubber o-ring, but it didn't look bad at all. See the picture of the piston below. I did take a india stone and work over the "bump" in the cylinder to smooth it down just a bit. I put everything back together and the rockshaft is even worse falling faster. I don't know if its because I stoned the cylinder or the gasket between the throttle valve and the rest of the power trol housing is missing when I put it back together. Im not sure exacly how the power trol works. Correct me if I am wrong, but the hydraulic pump on the governor housing is always running when the gear on the pump is engaged-correct? So the fluid circulates back to the power trol housing and back to the pump until the lever on the power trol is pushed one way or the other. Then fluid goes into the rockshaft housing via the throttle vavle right? What keeps the fluid in the rockshaft housing, hence the rockshaft piston under pressure? Is it the checkvalves in the power trol? I pulled the check vavle and inspected each ball, but there was no smoking gun? I have read that deere has a publication specifically on the rockshaft operation and housing. Does anyone have that PN handy on the power trol manual? In times past replacing the O-ring and leather on the rockshaft piton had worked. Now I am wondering if the rockshaft cylinder is too far out of spec? See pictures?

The red arrow on the power trol shows where the gasket was missing between the throttle valve and the rest of the power trol. I was wondering if that would cause internal leakage to fluid that is supposed to go to the internal rockshaft piston? I should have replaced the gasket before I put it back together but the perimeter of the gasket was in good shape.

The Powr-Trol is covered in the Hydraulic Equipment manual, SM-2011.

YOU MUST REMOVE THE ROCKSHAFT HOUSING FROM THE REAR AXEL TO REPLACE THE CYLINDER GASKET.

Not a waterloo guy untill the ng's but I see several problems. I never re use hydraulic seals. Any dent, scar, nick or flat spot and it's gonna fail. The pics show your piston is scared as well as the cylinder bore. You know you needed a new gasket cause you mentioned it. Looks to me like there is too much free play for that O ring to flop around.

If it were me I would lightly hone the cylinder, put in a new piston, gaskets and seals. If you just want to make do, lightly home that cylinder, put in new gaskets, a new O ring and two leather washers. When an O ring has enough room to roll like yours does it won't last. I would also work on the edge of that cylinder so it won't damage the new O ring going in. JMO

If I understand right ? The gasket around the throttle valve is missing ? If so then that is likely the leak. It has to hold back the oil from leaking back into the reservoir. You should be able to check for piston leakage with the piston back in hold something over the hole (like thumb) in the housing where the oil comes in to seal it and work the piston in and out it should have suction on it or you can many times see where air /oil flows out around it if o-ring is leaking bad.

Fred - I had the "no hold" troubles on my JD 50 rockshaft. It has the same PowerTrol as your tractor. My problem was leakage around where the cylinder bolts to the housing, and it can only be accessed as donmyeil said, by removing the whole housing from the tractor. The bolts (5 if I remember right) that held my cylinder on were only finger tight, and should have been somewhere upwards of 100 ft lbs. I don't remember if your hydraulic oil is leaking into the transmission/rear end - that's where it goes if it's leaking around the cylinder like mine was. Another possibility can be a crack in the cylinder. That is mentioned in the service manual. If cracked, the oil will leak into the rear end housing, and you'll soon notice an overfill condition there. The PowerTrol service manual is real good - very detailed and complete - I recommend it. Good luck - and please follow up after you figure it out - we'll all learn from it that way.

Listen to Donny's post. Some if not all the problem might be a blown
gasket between the rock shaft housing & cylinder housing.

Thanks for the feedback. I don't think its the gasket that holds the cylinder on because I am not losing any fluid to the transmission, nor am I losing any hydraulic fluid at all. My loader floats down as well and a guy is telling me its in my power trol. Perhaps the checkballs not holding?

Thanks Mike,
I blew compressed air into that hole in order to push the piston out of the back of the tractor. The more I think of it, missing that hunk of gasket at the throttle valve should let fluid out between the power trol housing and into the rockshaft housing, bypassing the cylinder with its full force. My 45 loader also drifts down. I wonder if it is a weak spring in the check ball area as well?

On order through Deere today! Thanks!

Thanks, yes, I know that Im just don't believe that is the problem because Im not losing any hydraulic fluid to the transmission. Really wondering how the power trol check balls work.

Fred , If it is leaking where My 60 was it won't be losing the oil into the tranny, The
part of the gasket was blown out on the oil supply hole & it would just blow the oil up
around the connecting rod to the piston. I had the cylinder face machined & it was slightly
warped. Replaced the gasket & reassembled everything. As a Test I can put a 8' National back
blade on the tractor over nite & it won't go down one bit. I would also replace that mounting
gaskets you said was partially leaking. Getting your Hydraulic lines out of the rock shaft
housing can test your religion.

I never thought of it leaking internally there as most have suggested they leak into the trans case. But you have a good point. I think I'm going to try the easiest method first and try replacing the gasket between the power trol and the rock shaft housing. Since I know that was bad.

Fred I would do the same as you, go the easiest route 1st.
replace what you can see is wrong, and if needed go deeper
& pretty sure you could reuse that gasket..