Steering Cylinder Rebuild
The steering on my PT1850 was getting tempermental turn the steering wheel and nothing would happen for a bit. Then is stopped working all together. I checked to make sure I had not sheared the pin holding the steering wheel on. That left either a bad steering valve or a bad cylinder. I assumed it was the cylinder and Terry confirmed this so I ordered rebuild kits from PT (part #’s and prices). I also ordered some hydraulic fittings etc to better allow me to test my tractor.
I plugged and capped the suspected bad cylinder and I was able to turn the tractor some and brought it into the barn. I purposely left the cylinders attached to the tractor and used a pipe wrench and a cheater pipe to break the threaded cylinder ends loose took quite a bit of effort.
Then I removed them from the tractor (capping the cylinder ports and plugging the lines) and took it to a friend’s shop where he and I rebuilt them. It was nice that he knew what he was doing. We cleaned the cylinders and then clamped one in a vise and unscrewed the loosened end.
We pulled out the assembly and saw the broken o-rings on the piston. (sorry about the bad picture - the camera was acting up, often refusing to work at all).
Undid the piston nut holding the piston on by holding the assembly vertically in the vise by the swivel and then using a wrench. Then the shaft was held wrapped in a cloth not touching the jaws but the shoulder of the piston resting against the end of the jaws. The shaft was driven out of teh piston by hitting the end of the shaft with a brass punch (the piston hits against the jaws keeping it from moving so the shaft has to move instead)
The shaft can then be taken out of the removable end of the cylinder seen from the side earlier.
It is important to note the orientation of the Dirt Seal/Wiper as shown below:
The O-rings were removed taking care not to score the metal, all the parts cleaned and dried. I replaced the piston with a new psiton. All the O-rings were replaced. Both sets of parts were from Power Trac. When reassembling, everything was coated with oil before assembly. The threads on the end of the shaft were then cleaned with methanol and dried before adding medium strength Locktite and the nut. Put them back on the tractor and everything works great.
I did not have a small enough hone for these cylinders so i will likely have to redo them sooner than I might otherwise have to.