Well if it were me I would slip the steering control valve out and pull it down. Those units run $1000.00 and up from the dealer, may find a whole sale dealer cheaper. The big thing is to clean the area, remove, draw/scribe lines down the unit, disassemble unit keeping you parts in order, you want to check the centering springs and pin, and check ball and seat. The gland in some unless leaking is a pain to remove and seal so most will not remove them. Like alrman said the unit has to be timed with the shaft and rotor. They make a tool to install the centering springs three at a time and it can also be done without it but it is a pain. Can you tell if yours has a canister under the valve, they have several different valves. Your machine only having the 700 psi may be dumping the oil back to tank or steering pump/priority valve issues causing the low pressure also. The thing is when running it turns and locks, centering springs and pin, check valve and ball, a dealer should be able to pull it down/ check/ reseal in a hour if you pull it off. It has to be inspected before parts can be ordered so you know what is needed. I will give it some more thought also.