Can anybody point me in the right direction to repair this fault? It's only retracting that the boom is slow.
Before we get into hydraulic problems are the boom wear pads in good shape? If not the boom droops down and binds up and the cylinder really struggles to retract the boom. You'll swear you have a hydraulic problem and the boom is just bound up. Scope it all the way out and then rest the forks lightly on the ground to take the droop out and see if it retracts a lot faster. If so get new wear pads and lubricate the boom. Start there first. If resting the boom makes no difference then, if you can, swap the hoses on the extend cylinder and see if it starts extending slow and retracting fast. If it stays the same let us know and we'll go from there. If we have to then we'll get into counterbalance valves on the extend cylinder and possibly circuit relief valves on the main control valve. Let's not get too far ahead of ourselves to start with though. Let us know. .