Replacing 3 point lift piston and rings...

Hey folks. Finally had the chance to take the top cover off the tractor and fix the rockshaft cylinder leak in my 1955 TO-35. Got the cylinder off and need to get the piston out. Any easy way to do this? I was thinking about using a rubber tip blowgun to shoot some compressed air behind the piston through the oil hole on top of the cylinder.

The reason I am doing this is because the lift sinks immediately when you step on the clutch. Taking off the left side inspection cover you can see a steady stream of oil pouring out of the cylinder bore. So, it seems that a new piston and rings are in order at minimum which I have ready to be installed. Looking inside the cylinder it seems to be in remarkably good shape for being 60 years old. There is some rust staining inside the bore and some fine scratches. If it was inside an engine I would give it a light hone and call it good.

Is there anything I should do to the cylinder before putting the new piston in? I was thinking about just polishing the bore with fine crocus cloth and giving it a thick coat of oil. This is an early TO-35 with the 2.5" bore cylinder, if it makes a difference on anything.
 
That's how I did it. I turned the pressure down a bit and then used my blowgun in "bursts" and shot the piston into a bucket with a towel into it. Kept it from flying around the garage and prevended damage to the piston. Don't need much pressure....
 
Once you get it apart, look down the wall of the cylinder. if you see ocean waves in the walls, you probably
have internal leakage contributing to your failure mechanism. Honing it out only makes the clearances larger.
You either need a new cylinder or you can try to re-sleeve what you have with a sleeve possibly made from
un-obtanium.
 
Thanks, I will check it out. If there are no waves or gouges I will put it back together with new piston and rings and cross my fingers. A new cylinder is $209.00, so I suppose it is worth trying the piston and rings first.
 
Popped out the piston with compressed air. The piston and rings have many scratches which I suspect are from debris or shavings getting in there. The cylinder has a couple of lengthwise scratches in it but no waves or anything like that. I am smoothing down the bore with 100 and 220 grit sandpaper as I have done with small engine cylinders before. I am thinking that if I can smooth the scratches out to where the depth of the scratches is greatly reduced and they have no sharp edges I can get a few more years out of it.

We are currently looking for a new house and I really don't have an extra $200.00 for a new cylinder. If this fix allows me to move all my implements easily and the lift doesn't immediately sink when I step on the clutch then it should be good enough for now.
 
Replace the middle ring with an 'O-ring'. then it will act like a Ford lift... cause that's how Ford's are put together.. your cost should be around 35 cents.....
 
Or, perhaps I could just swap in an entire Ford NAA 2.5" piston with the O ring and washer?It seems to me that this would be easier on the
bore or the cylinder than the metal rings would be.
 
I've decided to reuse the original cylinder for now. I took it to a machine shop in hopes of having it sleeved. They said they couldn't sleeve it but could likely hone it enough to knock down the scratches and high spots. The guy thought this would restore most functionality to it. Will keep you posted as to how it goes.
 
Another question. I have read that it is a good idea to replace the relief valve on the pump whenever doing hydraulic work. As I recall, there is some turbulence coming from around this area. My tractor is an early TO-35, would it take the 2550 psi relief valve, part number 883402M92?
 
(quoted from post at 14:47:11 11/30/16) Another question. I have read that it is a good idea to replace the relief valve on the pump whenever doing hydraulic work. As I recall, there is some turbulence coming from around this area. My tractor is an early TO-35, would it take the 2550 psi relief valve, part number 883402M92?

From the parts book.
883402M91 1 (A) Valve Assembly, Safety (3000 P.S.I.)
180962M91 1 (B) Valve Assembly, Pump Safety (2000 P.S.I.) (Order 891844M91)
****************************************
(A) - Used Tractor Serial Number 168853
And Up.
(B) - Used Prior To Tractor Serial
Number 168853.
 
I went ahead and ordered the relief valve, turns out the correct part number is 891944M91. This can be replaced by just removing one of the side covers, right? With any luck I'll be ready to put the tractor back together this weekend but the valve won't arrive until next week.
 
Picked up the lift cylinder from the machine shop. They did a great job honing it out, the scratches are quite faint now. Installed the new piston and rings and bolted the cylinder to the lift cover. Anybody have a picture of what the bottom of the lift cover is supposed to look like when assembled? I want to make sure that I got the linkage for the pump control and draft control reassembled correctly. I could only see one way it could go back together but would like to be sure.
 
Got it back together last night. Would have been a simple job except I did not assemble the control linkage right the first time and ended up with the lift arms in the all the way up position. Took it off and corrected it, reassembled. I haven't tried it under a load yet but the arms seem to raise and lower correctly and the cylinder seems to maintain some pressure with the pump not running whereas before it would leak down in a few seconds. Hopefully it works the way it should now.

One thing I wonder, under normal operation (not using remotes or draft control, just mowing) does one need to keep the oil level all the way up to the full mark on the dipstick? Right now I have it right at the level of the lowermost bolt in the side cover. I figured I would leave it here so I can take off the inspection cover to replace the safety valve when it comes in. Where is the valve located anyway?
 
Last night I hitched up my grandfather's old Dearborn 2 bottom plow to the TO-35 and moved it around to try out the repaired Ferguson System lift. She lifts it like a charm now, the pump doesn't struggle to hold it up like it used to. When you shut the engine off with the plow raised all the way up it will drop to the ground in about a minute, which is fine for my purposes. That might even improve once the piston rings get seated good and I replace the safety valve. When the TO-35 hydraulic system is functioning properly how long do they usually hold up an implement with the engine off?

The Dearborn plow was given to me recently by my grandfather's best friend, who purchased his farm equipment after he died. The plow was purchased new along with a Ford 8N back in the early 50's. It is surprisingly heavy for a tractor this size. Supposedly, the geometry of this plow was designed for the N series and didn't work so well with the later tractors such as the 1970 2000 that replaced Pa's 8N. I figure the TO-35 is going to be closer to the 8N than the 2000. Certainly, it should work well enough for a little garden and wildlife food plots.
 

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