Fordiesel69 263 #1 Posted October 10, 2014 I took a factory bolt out of my 312-8 and took to the store, it was only grade 5 so that is whet I got, but longer for my 1027 hr 314-H. Someone had thru bolted it with smaller bolts and nuts. Is grade 5 adequate? Seems foolish. The guys story was that the tranny loosened up and the bolts got lost. Share this post Link to post Share on other sites
Desko 610 #2 Posted October 10, 2014 Grade 5 has been in my dads work horse since 1983 with no cracks or loosening up so id say there fine but id go with grade 9 if your going to push snow or plow a garden Share this post Link to post Share on other sites
CasualObserver 3,408 #3 Posted October 10, 2014 Grade 5 will be fine... truthfully, Grade 2 (common zinc coated cheap bolts) are fine for most of the bolts in these tractors. The grading is the hardness of the bolt... what it's going to take to break it or shear it off. Most of the bolts on these tractors are just holding stuff together with very little shear forces in play. Using Grade 8 or 9 is a waste of money. Remember, the harder a bolt is, the more brittle it is. 5 Share this post Link to post Share on other sites
Desko 610 #4 Posted October 10, 2014 Grade 5 will be fine... truthfully, Grade 2 (common zinc coated cheap bolts) are fine for most of the bolts in these tractors. The grading is the hardness of the bolt... what it's going to take to break it or shear it off. Most of the bolts on these tractors are just holding stuff together with very little shear forces in play. Using Grade 8 or 9 is a waste of money. Remember, the harder a bolt is, the more brittle it is. True very true, what I'm getting at is it has more tensile strength and a higher torque value, but I agree that grade 5 will suffice what I was saying is a higher grade the less likely it will break IMHO but I am no bolt master just a diesel mechanic in training and have only had one wheel horse transaxle out. Share this post Link to post Share on other sites
jrc0528 20 #5 Posted October 10, 2014 I would stick with the factory spec for most bolts, unless you have re-engineered (modified) something and now require stronger fasteners. The transmission mounting bolts aren't particularly loaded in shear, but they do take quite a tensile load any time the tractor is pulling (or pushing) hard. Share this post Link to post Share on other sites
pfrederi 17,905 #6 Posted October 11, 2014 Better to break a bolt than to strip out or fracture the cast transmission case 1 Share this post Link to post Share on other sites
gwest_ca-(File Mod) 11,104 #7 Posted October 11, 2014 You can drill a broken grade 5 bolt to get it out but you will not drill a good broken grade 8 bolt. Garry 1 Share this post Link to post Share on other sites
squonk 41,458 #8 Posted October 11, 2014 If you do enough to break a bolt you will probably crack the frame anyway. Share this post Link to post Share on other sites
AMC RULES 37,134 #9 Posted October 11, 2014 There were no broken bolts here... Share this post Link to post Share on other sites
Tim Bergfeld 55 #10 Posted October 11, 2014 (edited) If the bolts just loosened up then sounds like they were not tight enough if that's the case put some lock washers on it tighten it good and check it after you use it a few times. Tim Edited October 11, 2014 by Tim Bergfeld Share this post Link to post Share on other sites
