You MUST post Brand of Jacks. I will assume Powergear. If so, look underneath at the bottom collar where the silver piston goes in the housing. SEE if there is a Grease Zirc. If so inject standard chassis grease into the Zirc until you see the lower seal start to bulge or you see the grease starting to come out. THAT will fix most Powergear fail to retract the last 2 inches. Do all 4 or 3 Jacks. Some have 3 jacks and some have 4 jacks. IF HWH the only lasting fix is to replace the sticking cylinder with a new or rebuilt jack cylinder. Doug