My 15 year old 2.5 ton Blackhawk floor jack pumps up OK, but the jack handle slowly comes up when weight is on the jack. I twisted the handle tightly to set the check valve but without sucess. Any ideas? This is a great jack otherwise, but there are so many cheap new ones out there. Thanks in advance

Sounds like the pump check valve is worn/dirty/damaged...
Have you tried the Proto/Blackhawk tech line - 770-787-3800.
Not sure if Stanley tool service shops handle these now ?

Thanks again