Hydraulic Control Valve

Bought a really nice old Ford 1973 F700 grain truck a while back - and everything is great, except the cable to the hydraulic bed lift was broken. The widow lady said it worked fine, "you just have to crawl under there and tap it with a hammer..."... And was she ever right about that!

I guess the broken control cable was a symptom, not the problem, because the spool valve shaft in the box is really tight... It takes either some light taps with a hammer - or a pry with a 2 ft lever...


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I pulled the shaft out expecting to find it scored, but it wasn't. I put it in the drill press and polished it till it gleams with various grits of body sandpaper (1000, 1500, 2000, 2500). Trying to keep from making it TOO loose - I sanded and polished 7-8 times, cleaning & refitting it each time and was really surprise to see that after all that it still just about as tight as when I started.

I then took a brake hone and honed the cast iron block, thinking maybe a burr or something was hanging, but it didn't help either. As close as I can feel - and as close as I can see - both the housing & the shaft are perfectly smooth...

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So my questions are - can a machine shop polish down this shaft a couple of thousandths or so, if the body putty sandpaper wouldn't touch it?? Any guesses as to if it was just made tight - or can they seize up or warp over time?? The ends of the shaft are not super hard, because a file will easily smooth up the very ends of the outer part of the shaft...


Thanks for any info,
Howard

Try rolling the shaft on a piece of glass.
If it has been beat on with a hammer it may have a slight bend.

or try fixing up a fulcrum and lever to increase your push pull power.

I'll have to look and see, but I think my 74 has a Harsh hoist on it. Mine is pretty stiff and touchy to say the least. Both it and the pto are hard to engage.

My 58 uses a triangular fulcrum with a lever to actuate. I've thought of swapping out the 74 so it has one, too.

I'm sure there is a shaft seal there. Have you replaced that? It may have swollen over time or if someone put some fluid in it that it didn't like.

An engine shop with with a pin hone and a decent selection of mandrels could open the hole up a little.

RT

Thanks for the comments...

Tracked down a good older machinist I'd never met before with a natural curiosity, hellacious workshop, and like-minded love of old iron this morning - and he got me going and we had a great time visiting, too! Even showed me some of the old iron he had hidden out back I didn't know about even though I drive by his place quite a lot. So it was a great morning! ha ha...

I'm surprised, but he found that the shaft was about 20 thousandths out of line. He got it straightened back to within 2.

I was surprised it was bent, mainly since I could rotate it in the bore - and I never felt a tighter/looser spot while rotating it... I guess the bore is so smooth & round, it was just uniformly binding all the way around...

Anyway, if it helps anyone else - that hardened shaft is so hard, not even auto body sanding paper will do anything to it but shine it up. So if you run into a similar thing, check for straightness.

Howard

The spool is probably chromed???

It was hardened in some way - sandpaper grit nor a file would touch it - even though both outside ends were relatively very soft. They both had peening from the prior owner hammering it - and a file cleaned that up very easily...

Did you get the emails I sent you a while back, Bob?? It wasn't any big deal, just wanted to ask you a couple of Versatile questions, but I never heard back from you after sending you a couple...


Howard

Chuck that lower end, into your drill press spin it up and dress it with some #400 sand paper...