Old Otis Telescopic Jack

So we have a older Otis hydro on maintenance that was installed in the late 70s that has a cantilevered 2 stage telescopic piston. It appears to be all original and I have never seen another one like it. Anyway we are having issues with the pistons getting out of sync and the jack seals are not leaking.

Anyone ever been into one of these? Do these have check valves like the Dover/Tke or ITI jacks? I found seal kits in the Gorman and texacone catalog but that's all I can find on these jacks. Any info on these would be greatly appreciated.

Controller tag info? Wiring diagram etc?

I’ll see if I can get some info off the tag, but it is all relay logic and I believe they called these Otis “Slim line” controls.

The Slim Line relays used on a controller will have an "S" at the end of the diagram number which stands for slim line relays.

there is a check valve on the bottom stage. can fill and test with varsol or some other mineral spirit to check for leaks. there is also a packing installed upside down on the bottom stage, this seal is most likely your problem. you will need to pull both stages to get at the check valve or bottom seal.

https://texacone.com/IECHI/Head/Details/46?DrawingId=62