Thanks.  One of the bucket cylinders has been replaced, the other and both lift arm cylinders are original (and as you say, are 40+ years old - though they may have been redone at some point in that 40 years).  The valve assembly had half of the lever pivot pin center retaining bracket broken off, pin replaced with an undersized pin welded on two added outside brackets.  I can fix that, which will remove a lot of play in the levers.  Before I start that I'll get that "O" ring assortment and find a hydraulic shop.  The manual calls for Type A transmission fluid, but that sure isn't what's in the tank.  Looks like 10/20 Universal Hydraulic fluid is in it now.  Any problems with that, or should I replace with Dexron/Mercon when I get the rubber replaced?

Ed