Don't mess with the c-clip , the balls and spring for the detent (float) are inside that larger cap , you want to make sure that cap doesn't slide off the spool , like Tazza said push the boom spool ( the one with the c-clip ) from the front and when you do grab the back , there are two 3/16 allen headed screws on the front on two on the rear of each spool , a 1/4 drive 3/16 allen socket makes this job easier , also if you have a 1/4 drive round spinner ratchet then once you break the bolts with the ratchet it saves alot of time and energy to spin the bolts out and then during reassembly back in till snug then finish them off with a ratchet , different serial number designs of the 753 you will have to take different things out the way you will probally have to undo the fuel tank fill hose and the pressure hose with the 90 fitting on the end of it that goes into the gear pump to be able to get the spool all the way out the valve ----------I can do both spools in 2 hours if all goes well , I'd say it could take you 3-4 if you never done it before -------------you don't really need a complete controll valve kit as it will come with alot of stuff you don't need and usually cost about $90 , all you need is 4 spool seals and I would put two new rubber boots for about $10 , it is possible you machine is newer and there will be two orings under the plates in the front that hold the seals in place , you would know if this is the case before disassembling as there will be two electric solinoids mounted on the front side of the valve where the spools come out , you could have the black quad rings , orange colored cup seals ( no longer used and replaced ) cream , green or purple colored seals , all the different colors will be replaced with the green ones , as mentioned make sure you put the lip side of the seal facing in towards the oil , if not you will be doing it again --------good luck and let everyone know how it goes