Sunday, March 15, 2009

It’s been a couple of weeks since I’ve posted anything. Mainly because about two weeks ago I had an Oh-S___ moment and wanted to be sure I could effectively recover before I wrote about my event and the outcome. For those reading this just because, the next few paragraphs will be about as exciting as watching grass grow. However, for those of you truly interested in the mechanics of these old tractors, you might learn something.

I was working on the lift cover to clean it up in preparation for painting. At the front of the cover, approximately centered, is a threaded plug covering the bore for a check valve designed to hold oil in the lift cylinder and to hold the arms in a raised position. If this valve is not working properly, the arms will not raise or will be jerky when they do raise. The valve can be seen from the underside of the lift cover, through the ports in the cover.
This particular valve would not budge when I tried to move it using a screwdriver as a lever. As a matter of preventive maintenance, I decided to service this valve and clean up the bore in which it moves. I had performed this service on a couple of previous lift covers, with good success.

While the service manual gives instructions on removing this valve, a great video, titled Hydraulic Repair for Ford Tractors available from J & D Productions, Inc., Metamora, MI, provides the most practical method of removing this valve, using a fine threaded 3/8” bolt and moving it incrementally with the continued addition of flat washers. These particular shuttle valves have three spools, a hollow shaft, and a port in the shaft between two of the spools with an O-ring around the largest spool for an effective seal. The shaft is threaded up to the port allowing a bolt to be screwed in for removal.

Removal of this valve was pretty straight by the book and it came out with little difficulty. After cleaning it and replacing the O-ring, I lubed it and re-inserted it into its bore. This time instead of screwing the bolt into the shaft and tapping it in using the bolt, I used a piece of 5/8” steel rod to drive it in. It has to be driven in since there is a slight constriction in the bore to, I presume, limit forward movement when the valve is doing its job. It went in with difficulty and, once in place, still would not move in its bore. Obviously I had not either polished it sufficiently or cleaned up the bore enough. When I repeated the process to remove it, I thought it came out too easily. When I pulled out the bolt, however, the only piece that came with it was the first spool. I had broken the shaft right at the port. Those valves are hardened which also makes them brittle.

That was my O-s___ moment! The remaining two spools on a hollow shaft with no threads was still stuck quite tight in the bore. It was positioned right over the ports in the cover without any way of moving it through those ports. How in the h___ was I going to get the remainder of that valve out? Although I had a spare lift cover, I didn’t want to go through all the work of removing the linkage pieces from this cover and putting them in my spare and then having to junk what was otherwise a perfectly good lift cover.

I sent an e-mail to my friend and tractor restoration mentor, Ron Kingland, explaining my dilemma. He called me the next day to offer some advice. He had the same thing happen to him sometime ago and was successful in removing the remainder of the valve using a 5/16” concrete anchor. When neither of us was certain that I could locate the same type of anchor he had used, he agreed to send me a couple of them. Several days later, they arrived in the mail. In the meantime, I had cut, drilled, and tapped a short length of 5/8” steel rod to serve as a coupler between my slide hammer and the concrete anchors.

That evening I went to my shop with some trepidation, hoping this would solve my problem. Driving the “nail” that serves to expand the anchor at its base, I attached my coupler and, using the slide hammer, began the attempt to pull the remaining valve piece out. I found that I could move it, but it wouldn’t move past the slight constriction in the bore. The slide hammer pulled the anchor out of the shaft every time. Now what? With a flashlight, I could see that the bore in front of the valve section was crusted with rust and other crud from years of little use. I tried wrapping a piece of sandpaper around a drill bit to polish up the bore with little success.

Another call to Ron. This time he suggested using a small flap wheel to clean up the bore. Unable to find any that small (the bore is approx. ¾”) I ordered three from Amazon.com. Shipping was prompt and a couple of days later, they arrived. These flap wheels have a 1/8” shaft allowing them to be used with a Dremel type rotary tool. I had previously purchased a flexible extension for my Dremel and used that to enable me to insert the flap wheel further into the bore of the valve than would have been otherwise possible using just the Dremel. I polished that bore in front of the valve until it shone, then cleaned it up with brake cleaner and some paper toweling wrapped around a dowel. Then I inserted one of the concrete anchors once more and set it in place. After spraying the bore with WD-40, I attached my slide hammer and began removing it. I breathed a sigh of relief when, this time, the remainder of that valve emerged from the bore. I couldn’t have been more pleased.

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