In Reply to: Re: 53 three point wont lift posted by Doug on June 13, 2018 at 12:15:18:
Old vs new unloading valve would be metal "o" ring vs 'rubber' I believe and operation would not differ. Back pressure line should not go directly into the return port, although I have heard of some that do (always assumed someone bent/installed it wrong). All I have ever seen dump out well toward rear of hydraulic compartment. Over pressure relief valve (near vertical pressure tube at right front of hyd compartment)will only open if hyd flo is blocked. If lift is working, this may be accomplished by chaining the lift arms down and giving a lift command. If lift not working that "chaining" will not work for measurement purposes. Flow can be blocked by plugging the accessory plate as in the attached (effectively blocking flow at top of vertical tube ...circled). If you wish to talk, send me an e-mail with a phone number.