I have and older Model MTD 14/42 Industrial Commercial LT It has 7 speeds need an owners manual too see how the deck is suppose to look so I can try and adjust it and see if it might be off deck vibrates when mowing had deck fixed and new spindels put in could not find Model number or Serial number for lawn tractor

SOURCE: removing tractor deck to change belt and blades?

if i am thinking of the right model you may be able to get away with first taking off the blade, then to remove the deck should be a number of bolts under the chassis and on top of the deck where it meets the frame... you can get your parts here if your having trouble finding them
 http://www.ordertree.com/modelinfo/MTD/13A1674G401-%281997%29/62.13A1674G401-%281997%29.1.1.1.html

SOURCE: owners manual for a craftsman model 917255812 lawn tractor

Hello:

>>You can Use the Site Addys at this Site Addy; http://www.yetmans.mb.ca/antiques.html to Search and Locate New/Used Parts or for Manuals for this Unit.

Respectfully

John

SOURCE: Replace V belt on mastercraft 38 inch 12 hp lawn tractor

Hello

The Breakdown of the Unit Usually Shows the Belt Routing.
>>To View a Breakdown of this Unit Go to this Site Addy, http://www.searspartsdirect.com/partsdirect/index.action?sid=PSHx20080114x00001 and Enter the Model Numbers and Click Search. From this Page you can View Diagrams and Parts Lists for you Equipment Using the "View Sub Components" Section Near the Bottom Left.
Please, Do Not Hesitate, If you Hit a Snag or this Does Not Correct the Problem, I am Here if You Require More Assistance.
Hope this Helps. Let me Know What Happens, Please. May the All Mighty Bless You and Yours. Be Safe and Be Happy. Thanks.

Good Luck

Respectfully

jbridger (John)

SOURCE: MTD Lawn Tractor: Constantly shredding deck belt...

I have the exact same model MTD tractor with same problem. It began when the bolt that extends through the idler arm assembly broke and subsequently damaged the pulley. Upon examination of the broken bolt, I found that the threaded end that extends below the deck is significantly smaller that the rest of the bolt. I got a larger bolt with the same size threads, bored out the hole through the deck and it made the whole idler assembly much stronger. the deck still has some vibration and some unusual belt harmonics, but it appears to be working. Compared to most other tractors of this size, this deck is very complicated.

SOURCE: yard man mtd 20hp 46

go to the online web site for the yardman this will give you the guide on how to replace the belt.