what hoses are you replacing that requires the removal of the carriage? This seems a bit unusual. Most of the time replacing hoses in the mast when the carriage is in the way, usually if it is a main lift hose, you can just raise the carriage or mast channels up out of the way and chain it up to the mast cross beams. Now if you decide to go this route make sure you use certified 3/8 or larger chains and double wrap them to insure the stability. The last thing you want is a cheap chain breaking on you, that could be deadly.

Of course if your insistent on removing the carriage generally you just disconnect any attachment lines attached to it , disconnect and cap off the main hose to the center cylinder to prevent the center cylinder from raising, remove any hoses on the center cylinder crosshead assembly and lay them aside, then disconnect the lift chains at the cylinder where they are attached, and it will drop out of the bottom when the mast channels are raised.

raising the channels when the lines out of the way and chains are disconnected will raise the channels up to clear the rollers so you can back the truck up away from the carriage. I would get a pallet and leave the forks on the carriage, raise it and set the forks onto the pallet and get a c-clamp to hold them down. Set the park brake and block the steer wheels temporarily. Raise the channels till the inner channel clears the carriage rollers, then remove the wheel blocks, unset the park brake and drive back away from the carriage.

Naturally you would want to get the pallet in place before you start anything though ;o)