mechanic mark
Lawn Pro
- Joined
- Jul 15, 2013
- Threads
- 175
- Messages
- 7,484
Most residential mower decks have a weak spot. Idler arms are assembled to deck at factory with 5/16" or 3/8" diameter bolts, much too small to handle torque & movement. A grade 8 standard coarse thread bolt 7/16" diameter 2 1/2" long with a shank of 1 1/2" with 2 flat washers & a self locking nut will solve your problem. A 7/16" drill bit is needed to make repair of drilling through deck, bushings, idler arms, etc., machine shops are well equipped to make this repair for a small fee. When servicing tractor, apply grease or oil as best you can to shank of bolt idler arms area.
This is the factory bolt that my son and I replaced, as you can see bolt is stretched & warped, it was a grade 5 bolt with size 3/8" diameter & 1 1/2" long.
Last edited: