By al petit on Unrecorded Date: Edit

can any body tell me if a grade 12 aircraft bolt would be stronger in the center axles on a max or are they more brittle my bolts are 3/8 by 2.3/4 and grade 8s but under very hard riding im breaking them about twice a day and they arnt sloppy fits either they are reamed to a light pressure to install them can you go to 7/16 with out making the axels any weaker they are solid 1045 im not sure i want to make the holes any bigger because the machine weighs 920 empty this is not a plastic max its all aluminun body and roll bar and ideas to help with this problem. AL

By liflod (Liflod) on Unrecorded Date: Edit

make sure the shank of the bolt is holding the load and not the threads. I had the same problems with my Attex. I ended up buying bolts about 3 or 3 1/2 inches long and then cutting them down. That the only way to get a longer shank.

By Fred Sowerwine, Montana's Max dealer (Fred4dot) on Unrecorded Date: Edit

Al, Not sure about the hardness thing, I think harder is more brittle. The stock bolt that Max use is a 7/16 x 2 1/4 grade 3.

I think your bolts are just too small (maybe too hard). The other thing to check is to make sure the threads don't go into the axle - should be about 1 1/8 inch of solid bolt. I would make sure the bolt hole is smooth and there is no play between the axle and sprocket tube. You might also want to check sprocket alignment and bearings as usually something else is wrong when you break axle bolts, especially if you have not been having any trouble. Chains too loose will put all the stress on one bolt of your drive axle. I'm assuming that by solid 1045 that you mean 1 1/4 inch diameter (I'm not up on metal description terminology)

Good luck in figuring it out.

By Timothy Schotanus (Mudbuster) on Unrecorded Date: Edit

I had played around with 2 bolts in a max4 a while back but can't give you the results of the test because shortly after doing it the tranny blew and I sold the machine.

By dt5428 on Unrecorded Date: Edit

Hey Al I am an aircraft mechanic not sure about the grades but if nobody has an answer here I can do some research at work and try to figure it out.All the bolts and screws we use are NAS,AN or MS part numbers but we have some books that break them down for us.I can look up some of the landing gear bolts that are in the high stress areas and see what type they are using also.Email me if you need more help and I will do what I can.

Later,Dan

By Attex Bob on Unrecorded Date: Edit

Ditto

By promoza on Unrecorded Date: Edit

hey Al all my bolts are 7/16 grade 8 i havent broken one yet and mine are in a 75 rim i did replace all the bolts with new one but that was 3 years ago you mite think about going up in size
Good luck

By david berger (Davidrrrd) on Unrecorded Date: Edit

petit:
defenatly drill them for the 7/16 as that buggy's too heavy for 3/8 bolts, and yes the greater the hardnes the more brittle,
grade 12 then would shater like glass if your grade 8's were brakeing,
so many postes have given you the same advice:
grade 8 long enoph for shank only to be inside the drive tube or axel, this may require cutting off some threds from a longer bolt,
no need to tighten them down agenced the tubes ether, just use a plastic ended stopnut so it stays on the bolt and your good to go,
it's weird to find tiny 3/8 bolts in the max machines unless it's a realy old unit,

By Joe on Unrecorded Date: Edit

Stock max bolts are a 2 1/4" long, 1 1/2" or so long shank, GRADE 5, fine thread.

By Fred Sowerwine, Montana's Max dealer (Fred4dot) on Unrecorded Date: Edit

My mistake on the grade of Max stock. The bolts have three marks on the head - I thought that meant 3 grade, but research tells me that is in fact grade 5. Thanks Joe, for encouraging me to learn something.

By Richard Clark on Unrecorded Date: Edit

6x6 Freinds:

There are no easy answers to broken AATV sprocket bolts.

1. Bolt shank must be in contact with axle & sprockets not threads.
2. Use grade 5 only, not softer not harder
3. Do not drill oversize as it weakens axle.
4. Axles must be true
5. Bearings, bushings must be good, not too tight.
6. Frame must be true
7. Chains must be correct tension
8. Axle holes must NOT be worn out
9. Sprocket holes must NOT be worn out
10. Do not run knobby tires, will not skid steer correctly

If any of the above items are not correct then
bolts will break all the time.

Richard Clark
ROUTE6x6

By al petit on Unrecorded Date: Edit

thanks for the help i made new 2 inch od sproket sleves and put on new sprokets and i guess i missed that the thereads were a good 1/4 into the sleves thanks i should be in good shape now because i never had this problem before with the old sprokets i will test it this weekend thanks every body al petit

By Eugene kochnieff on Unrecorded Date: Edit

Hi ALL

Some of my thoughts on bolts, Firstly bolts are by design used to compress two surfaces. Bolts used under sheer are simply a sign of bad design.
This topic covers many opinions but given that max use bolts as a sheer device i fully agree with richard clarks remarks. For those who want greater strength, roll pins of a suitable grade should be stronger, but if they are you will only find the next weakest link in the drive train and that may be very much more expensive than a few bolts. For those interested there are a few web sites dedicated to bolts that will give you all the math etc, basically fasteners are a highly specialized field of engineering that most small companies have little or no expertise in what so ever.

By LAWPRESSMAN on Unrecorded Date: Edit

I HAD THIS PROBLEM OF SHEARING AXLE BOLTS AND FOUND THAT THE MAIN PROBLEM WAS THAT THE AXLE AND TUBE HOLE WAS EGG SHAPED. THIS SLOP IN THE BOLT HOLE MAKES THE BOLT SHEAR VERY FAST.
WE FIXED IT BUY REMOVING THE AXLES AND WELDING THE HOLES UP AND WE ADDED A WASHER TO THE TUBE AND WELDED IT IN PLACE, THIS MAKES THE TUBE THICKER IN A WEAK AREA. WE THEN REDRILLED THE HOLES AND MADE UP SOME NEW BOLTS WITH LONG SHANKS, SO WE HAD ALL SHANK IN THE HOLE AND NO THREADS. SO WE ELIMINATE ALL MOVEMENT IN THE AXLE CONNECTION.
A LOT OF WORK, BUT NO MORE PROBLEMS AND A LOT CHEEPER THAN NEW AXLES.

By Preston on Unrecorded Date: Edit

Folks

You should have looked at richards washers see

http://members.aye.net/%7Erclark/images/prr6.jpg

As he even sells them cheap, even cheap for us, 2$

Sam Preston

By Marc Stobinski (Jerseybigfoot) on Unrecorded Date: Edit

Another good solution is to use heat treated alloy shoulder bolts. The bolts are a precision diameter and designed to take shearing forces. I have used them for years on my Hustler with 25" Rawhides and 1 3/16" axles

By tropicjungleboy on Unrecorded Date: Edit

i found that with grade 8 bolts and 25 pound of torque WITH SAFETY NUTS ( in order to keep bolt under presure again sproker over axle no more bolt failure.............before as soon as regular nut get loose bolt breaks

By Fred Sowerwine, Montana's Max dealer (Fred4dot) on Unrecorded Date: Edit

Hey Isaac (tropicjungleboy), Where have you been? Haven't heard much from you lately. Good to have you back.

I also think having the bolts tight helps to prevent breakage. I have always used the stock bolts (grade 5) though. I also think tight bolts help to prevent hole elongation. Checking axle bolt tightness is one of my routine checks on machines that come in for service.

It is kind of off topic, but everyone should remember to check their tranny mount bolts on a regular basis also. I have had several machines come in with the nuts loose.

By tropicjungleboy on Unrecorded Date: Edit

thanks fred for warm reception!! i get myself deeply busy on my last creation.. a crawler mounted front cutter drum........good to produce on a single step basic subgrade material for roads from limestone soils....you can notice it at http://geocities.com/isaaceisenman/FRESADORA_FRONTAL.html

about tranny mount bolts..as a common sense ALL bolts on aatv should be dressed up with blue locking compound better knowed as locktite (but locktite is a trademark!!)........vibration associated with aatv ambiance releases unsecured bolts and nuts..........