Greetings all,
Several weeks ago, I was here seeking advice whether or not to rebuild and use the electric lift that came on my 126 project tractor, or to come up with some other plan to operate the Cat 0 3-point lift I am installing. As a result of those discussions, I was able to get my hands on a complete Hydraulic Lift assembly.
I have completely disassembled and cleaned the unit. All of the surfaces which will be painted have been sandblasted and primed.
Being a toolmaker by trade, I have access to machine tools, so I was able to recondition the parts. I honed the ID of the hydraulic cylinder bore to eliminate most surface defects.
The piston received chamfers to break edges that had displaced material, and the piston and seal groove were polished. The piston rod was OD lapped to eliminate surface defects.
The pulley had issues. It must have come loose a lot, because the ½” ID was worn and tapered .060 oversize. The set screw was probably stripped once or twice too, as it was currently threaded for 5/16-18. Interesting too, the tapped hole was very close to one end of the pulley. I bored the pulley to .690, pressed in a mind steel bushing, plugged the tapped hole, and had a buddy TIG weld it all in. I then machined everything to make the repairs invisible, and bored the pulley ID to .500. I drilled and tapped a new ¼-28 hole 180 degrees from the previous one, and located it midway along the .500 ID for strength and holding power.
As far as the pump body goes, much to my surprise, the bore in which the pump drive shaft rotates was not worn at all. My original thoughts were that I was going to bore it to clean, and then make an oversize drive shaft. The bore measures .502 and is not tapered. The unworn areas of the drive shaft measure .499, which would leave .0015 for radial clearance for oil. It appears to me that would be the clearance intended by design. Does anyone have any thoughts on that?
The shaft, on the other hand, was worn pretty badly, tapered down to .495, and grooved where the rides. I have a piece of O2 oil-hardening rod coming, in which I will make a new shaft. I can make it oversize just as easily as I can make it original size, so if anybody has experience with the clearance on these things, please let me know.
I am waiting on the arrival of the O-rings and backing rings I ordered to put it together again. I do have some thoughts I’d like some opinions on while I’m waiting….
I was wondering if it might be a good idea to drill a small hole, say .015 in the reservoir plug to allow air exchange. The volume of oil in the reservoir will change as the cylinder moves through its range of motion (about 2 cubic inches by my calculations). This will cause pressure and/or a vacuum, which could lead to leakage from the reservoir at the seals (I question how good the seal is at the reservoir stud). Does anyone else think this is a good idea?
I was also thinking of welding a small rod to the end of the reservoir plug that would protrude into the reservoir, with a mark at the 2/3 full line to serve as a ‘dip-stick’.
Below are some pictures of the progress so far. I’d have included more, but for some reason, even though I resize them to 800 x 600, most of my pictures are still slightly larger than the 100K maximum allowed size. I’m frustrated that I can’t share more.
Thanks in advance for your thoughts and advice.
(Or maybe it's a difference between these 12 and 13 fin blocks we see these tractors with...)
