I have a 1988 Dynahoe 490 with a thumb. When I looked at the machine the thumb was not hooked up but he fellow that I bought from said that it worked fine. He said that all you have to do is push down on the foot pedal on the RH side of the floor and use the bucket curl lever to to open and close the thumb. The bucket curl works just fine but I can't get the thumb to budge. The thumb has it's own hydraulic cylinder and 2 lines go up to a pin between the boom and dipper stick. There are to other hoses that go to the bucket cylinder for curling control. There is a small hose that goes from the pin to the foot control in the cab. When I push down on the foot control the small line seems to move slightly as it's being pressurized but nothing happens. The bucket curls whether i push on the foot pedal or not. There is a small reservoir container on the foot valve that is full of oil. I pumped the foot pedal several times and nothing changed, same problem. So, "I think" that the the foot pedal, might be ok because the line seemed to be pressurized to the pin. The lines connected to the pin between the boom and dipper stick are not leaking and if the thumb lines were crossed the cylinder would work in reverse, and that would be an easy fix to swap lines. So, I think that my problem is with the hydraulic pin between the boom and dipper stick. The fellow that I bought the machine from has no clue of who made the thumb. His father bought the machine used when it was 2 years old and it had the thunb on it. He's used it and it always worked, doesn't know what my problem is. I've tried looking on line to find something like this set up and they all appear to be set up with foot control valves going directly to the thumb. Very expensive set up even for the foot valve. I was hoping to find a new pin that I could just swap out. I can't find any Dynahoe option so that's a dead end. Does anyone out here have any info on who made this set up or know of a place for replacement pin? I have a lot of work where a thumb would be very helpful. Any help would be greatly appreciated! Thanks!