There is a Mfg tag rivited to the lift bed that states the Manufacturer is Hercules Steel Product Corp of Galion, Ohio, USA. It gives the Hoist Model as JDX, with a serial number of 96768. The pump itself has two sets of numbers on it, #7870 and #12560. There is no other info on the pump itself that I can see. The cylinder of the lift/hoist is about 30 inches long and has a diameter of about 9.5 inches, so as you said the opening on the cylinder is more than likely the fill. Thanks again for the reply.
Jim
