Craftsman deck problems 917.275390

Hey Guys and gals,

I am new to the forum and hope you can help me, been having some problems with the mower deck it is a 20hp 42" cut Craftsman i believe it is about 5 or 6 years old I cant remember when I got it.

Well here is the problem, I let it set for awhile after i put some new spindles, blades and belts on it before i parked it last october, used my dads mower for a while because my yard is 2 acres and his ztr mows it in 45 mins my craftsman 3 1/2 hours, anyway decided to use mine one day and started up ran good turn on the deck perfect cut for 5 mins then banging and framming so loud it shook the mower from the tires up.

I checked everything and the spindle bolts had come loose tightend them up for five mins ran good then loose again. Went and got some Allen head bolts and lock nuts and ran them through the bottom up, worked great, then another vibration and ticking noise for a couple of laps and it sounded like something came loose and gave way then perfect mower no vibration noise or shake thought it was fixed..........but then

I started hearing a sort of loping noise from the deck then it got louder and closer together looked down and pulley on new spindle was walking a little, stopped got it super tight, 10 mins go by and it starts again, go to stop to tighten again, when i stopped it spit the belt out and when i checked underneath i found that the twin idler pulleys in the middle of the deck it seems have come loose, you can move the idlers on their stand about 6-9 inches front to back and for some reason it will not tighten up and i am not sure maybe it is supposed to move like that also i can not figure how that pulley walked off again i got i lock nut and some loctite on it now so....

Any suggestions are welcome i know it is a little long winded but as you can see i tried everything i could think of