I"m thinking it"s time for you to purchase a manual. But I"ll try to help before you break something.
1. I hope you have removed the round cover on the right side to inspect the spool valve, right? Now there is a roller that is captive within the linkage, tie a tag wire to it, so you don"t drop it in the belly. Now spread the linkage and remove the roller.
2. Remove the square cover, just under your right leg while sitting on the tractor, two bolts. This is the stand pipe cover from the lift pump.
3. Now, DON"T remove the four large nuts under the seat, they hold the lift cylinder. Install a eyebolt or something to attach your lifting system to the front seat bolt female thread. Lift the cover just up and forward a little while you observe the linkage thru the right side round cover to clear internals. I"m thinking you will need around 20 inches of lift to clear housing, been six years since I worked on my 150, so I might be off some.
BTW, the rattle you are hearing, I believe is the dog bone that is attached to the rocker shaft and goes into the lift cylinder piston, there is NO direct connection to the piston, ONE way cylinder.
I hope I have you in the right direction, others forum members will correct me, if I have pointed you in the wrong direction.