axle/sprocket bolts

[dgeiman]

I have a Max IV I have recently replaced the entire drive train axles, sprockets bearings etc. My old axles had 7/16" diameter bolts holding the sprockets to the axles the new axles which I got from RR had 3/8" diameter holes and came with grade 5 bolts. The bolts on the front axles sheared off I replaced them with new grade 5, then the bolts on the center axles sheared off, I replaced with grade 5. The rear have not sheared as of now I would think they would have went first. My first thought was that I over tightened them and stressed them, so when I replaced them I backed off a little I also have them double nutted. The reason I did that was because the old blots use to come loose.
THOUGHTS?
One other thing on the way to my treestand there is an exposed tree root I cross could this have caused it? I do not run tracks.
THANKS, Dave

[wedge]

You can try Grade 8 bolts with Nylock nuts.

[dgeiman]

OK THANKS I will give that a try

[liflod]

Make sure there are no bolt threads inside the axle or sprocket tubes. Usually I need to buy 3 or 3 1/2 inch bolts to get the shank long enough so that no threads are inside.

[msafi65]

I have used 7/16" grade 8 for years with nylock nuts. In my experience the 3/8" bolts won't last at all,especially if the axle holes are 7/16. I drill new gear tubes undersize and pass a 7/16" bit through the axle and tube as a unit. If there is no play in the bolts they will last a long time. For stock tubes without any washers welded to the outside I use 3" bolts cut to length to keep threads out of the working points in the axle and tube. I'm surprised the rears didn't go first , they get a lot of load going up hill.

[dgeiman]

THANKS for ideas Guys. On the next chain adjustment (just put it back together) I am going to drill out all 6 to 7/16" and put in new grade 8 bolts. The new stuff came with 3/8" holes in both the sprocket and axles everything fit good when I put it together. I had a thought about longer bolts to keep the threads out of the hole but did not do it. I am running nyloc nuts a lock washer and a second nut the nuts have not loosened up as of yet.

These machines are a pain in the butt and fun to work on at the same time. I have had mine for 4 years and have had it apart a few times my wife just shakes her head. Where I run my machine is mostly flat (Marylands eastern shore) a lot of mud,swamp and marsh some flooded woods. It is timber property so there are a lot of logs, dead trees and such. The trails to my stands are pretty clear for the most part I only take the machine to the stand area to retrieve a deer or take something to repair the stand.
THANKS, Dave

[liflod]

Use a longer shank bolt. If the 3/8 bolts fit tight, there's no reason to drill them larger. AN bolts are closer tolerance than the off the shelf bolts.

[ARGOJIM]

I have used 7/16" grade 8 for years with nylock nuts. In my experience the 3/8" bolts won't last at all,especially if the axle holes are 7/16. I drill new gear tubes undersize and pass a 7/16" bit through the axle and tube as a unit. If there is no play in the bolts they will last a long time. For stock tubes without any washers welded to the outside I use 3" bolts cut to length to keep threads out of the working points in the axle and tube. I'm surprised the rears didn't go first , they get a lot of load going up hill.

If the sprockets were already 7/16 and the axles are 3/8 there's part of the problem, as whipperag recommends along with liflod the longer "body bound" bolts will help. I'd guess you'll have to go 7/16 unless you can get some cup washers to repair the sprocket holes.
If your sprockets and axles are 3/8 then follow liflod and go with the longer bolts.

[dgeiman]

The sprockets and axles are brand new maybe 10 hours on them none of the holes have egged. The axles and sprockets came with 3/8" holes in them. I spoke with the lady at Max parts she did some checking and told me the original factory bolts were 3/8" diameter and said they recommend grade #8 to get them at NAPA. I am going to change them to grade 8 first stay with the 3/8" diameter and get the longer shank if they still break then I will drill them out and use 7/16" diameter grade 8. should I use flat washers on ethier side of the bolt ? What are AN bolts ?
THANKS for all your help.
Dave

[dgeiman]

Well just got back from my week long hunting trip I changed all the bolts to grade 8 with a longer shank as suggested and put it to the test and no problems. THANKS for all your help.
Dave