I have a champ reach lift CRL-60 around a 1990 model. when I tilt it up and let off the valve it instantly begins losing tilt and multiplies with weight.(won't hold tilt) Our initial instinct was to rebuild the cylinder but a mechanic said cap off a line and see if it still falls, we did and it held, meaning it may not be the cylinder, we capped off the auto tilt cylinders thinking it was bypassing there, no luck (still losing Tilt with bypassing auto tilt), we bypassed a check valve and went directly into the hydraulic control valve, no luck, changed the lines to a different control valve that we know works for the boom, no luck, checked fluids, no luck. Please help!