I concur with all, you need to get a company out there. NWOV products are all discontinued. TK Access bought them about 4-5 years ago then TK closed down 3 years ago so parts and support are getting harder and harder to come by.

Do not make it worse trying things yourself, you are correct, there is a very small pit on this = NO REFUGE SPACE. If this is a sudden loss of hydraulic pressure when you are under it there is a break that will stop it, but it only needs to come down a foot to smash your skull or if your on top of it to throw you off the side of the car.

There are methods of running it up but that is not going to help you. If a Hydraulic elevator drifts it is certainly a leak somewhere, the piston packing seal, the piping or worse, in the valves itself. You'll never see it since it will drain back into the tank. It will keep happening until the root cause is found, that is for sure.

If you mess around and try to get this to pump on its own and burn out the valve body, I can tell you right now you are looking at a $2k repair and waiting 4 weeks (If you are lucky) for the part. O' rings and packing seals are easy but you're going to have to get a company out there.