The belt on this mower is worn out and I need to replace it, how do I take it off and replace it. The drive belt on a 22hp v twin hydrostatic 50" mustang zero turn radius mower. Thanks

Hi,
I will attach a link to the parts breakdown. The deck and its belt must be removed first. Once done the idler arm that tensions the drive belt has a square hole designed for use with a 3/8" ratchet or breaker bar. Insert said tool and rotate the idler arm to remove tension so belt can be removed and replaced. Link at:
http://www.mowerpartsweb.com/MANUALS/TROYBILT/769-03560.PDF
And the idler arm is pictrured on page 2 while the belt is on page 14. To get the manual with the directions, take this link:PDF Manual Web Archive (http://manuals.mtdproducts.com/mtd/Public.do)
And insert your model number and use 1 as the serial number. It is 769-03559 and you should refer to page 29.
Peace,
Clarke