Hello, I have a sears log splitter from 1981.It is a 5 hp, 10 ton with a 3 and 1/2 inch cylinder. It lost most of the hydraulic force. I am asking which to suspect first,as the worn out part. The cylinder or the pump. When I first use it and the fluid is cold it has more splitting torque than it does after using it and getting the fluid hot.However it never has the torque it used to have. What are my steps for troubleshooting my splitter? The model no. is 498.286692 the parts are not available however there are pumps that will fit it and there is a place that rebuilds cylinders. Thankyou for any assistance.