Drive Shaft Flanges...what kind of bolts?

[rmgill]

So, on my trip to Camden SC and back, I had an issue with an odd vibration that when I tracked it down was the Transmission to transfer box drive shaft bolts having worked loose. I was missing a nut and since this was a new transmission, I have to wonder if the split lock bots are at the end of their life. It was tightened back up and has held but I'm going to replace the bolts just to be certain.

What sort of bolts do I need here? Grade 5? Grade 8? The parts manual just specifies 1 1/2" long by 1/2"-20 bolts and locknuts. Do they need grade 8 hardware or are some sort of lock nut of lower grade sufficient for the task? Are the flex top expanding locknuts as installed the best or are the distorted thread locknuts better?

Mcmaster sells military specification sloted head flext top expanding locknuts but they're $3.89 ea.

 

[Varyag]

I can't really think of a reason not to use grade 8. Unless I am missing something.

 

[rmgill]

The lock nuts usually don't appear to come in a grade 8 rating. The Grade 8 bolts I can see easily (shear strength) but the nuts I'm not so sure since they're not actually under tremendous tension.

 

[doghead]

The deformed style lock nuts are available in a grade 9. Pretty sure the bolts should be grade 8. I think it's important to have the unthreaded part of the bolt, be as long as possible, in this particular use. Somewhere, I think I posted this before. I'll look some.

 

[doghead]

Look at this thread, it has a link to Fastenal, for the nuts.

http://www.steelsoldiers.com/deuce/43855-deuce-jackshaft.html

 

[Jones]

Doghead's right, the Fastenal link will take you to the correct nuts for the driveshaft bolts.
Since there is no "driving tab" on the u-joint flanges, the bolts have to carry the entire load. Grade 8 for sure.

 

[airmech3839]

rmgill......were you on I-20 on Sunday? I saw a deuce on I-20 heading toward ATL here in Augusta about 3pm??? Was a M35A2 with camo pattern and cargo cover...

sorry didnt mean to threadjack!!

I would want grade 8 if it were me....but I would not want to pay for grade 8....I am cheap...

 

[KsM715]

Arent the deformed style locknuts a one time use item?

 

[rmgill]

rmgill......were you on I-20 on Sunday? I saw a deuce on I-20 heading toward ATL here in Augusta about 3pm??? Was a M35A2 with camo pattern and cargo cover...

That was me.

 

[rmgill]

KSM715, they are. The slotted head locknuts appear to be as well as I had 4 vibrate loose. 3 were GONE from the front drive shaft from driving around on snowchains in the ice we had and I had one on the Transmission/X-fer intershaft go missing. I had replaced the front driveshaft nuts/bolts with some grade 8 bolts/nuts but since it is not usually used (lockout hubs) I figured I would be fine. When I realized later that I had more bolts going loose, it was clear that the slotted nuts are NOT up to task. I was actually wondering if I should drill them for safety wire to be **** sure.

 

[FireFighterHill]

Thought about using some industrial strength Lock-Tight on the bolt threads? I had some swaybar end links that kept coming loose, lock-tight was the solution.

 

[rmgill]

Well, I want to do it right really. Thread lock is good but not if it's the wrong bolt/nut hardware to start with.

 

[bassetdeuce]

Not to hijack the thread, but do the 800 series 5 tons use the same size bolts/nuts for the flanges?

 

[rmgill]

I'm not sure Doug. Check the TM. the deuce uses 1/2"-20 x 1 1/2" long.

 

[jwaller]

800's are bigger. tm says not to reuse those lock nuts but I'm sure like me everybody does. these type nuts wear out when you take them on and off. they should be replaced and I've started to use locktite on them as well.

 

[nk14zp]

800's are smaller.

 

[20-Years-USN]

What sort of bolts do I need here? Grade 5? Grade 8? The parts manual just specifies 1 1/2" long by 1/2"-20 bolts and locknuts. Do they need grade 8 hardware or are some sort of lock nut of lower grade sufficient for the task?

rmgill, yes Sir, definately go with the grade 8 bolt and a little Lock Tight. Remember the Lock Tight will act like lube, so if you're torque spec is arount 130 or so, you'll want to back off about 30 to 100 ft/lbs... but they can handle a little more torque if you want to run 'em down to 120 ft/lbs lubed. Here's a link to the 1/2 - 20 all metal (no nylon) lock nut in grade 9 (nine) and not too expensive in my opinion for what you're working on.

1/2-20 Grade 9 Yellow Zinc All Metal Top Lock Nut | Fastenal

Good Luck!