Threadlock or Never-Seize

[Deere Dude]

I am putting new brake backing plates on my campers 8000# axles. The 1/2" grade 5 bolts were almost impossible to get off, but I finally got them.
I got new fine thread grade 5 bolts and nuts but am unsure if I should put a lock washer or Lock-Tite or Never-Seize on them :confused3:. The old ones had a lock washer on but just unscrewing the bolts they got trashed. I almost had to grind them off.

 

[JJZ 109]

I use Never Seize on almost everything. In your situation I'd get new lock washers to secure the bolts if they had them before and Never Seize the bolts.

 

[sld]

For things that heat cycle or see vibrations Loctite blue is your friend.

 

[tjkubota93]

Blue loctite will keep them from loosening on their own. It will also prevent them from seizing.

 

[Mace Canute]

Blue loctite will keep them from loosening on their own. It will also prevent them from seizing.

I like using medium strength thread locker for just those two reasons. I will NEVER use any sort of lock washer on anything that I can apply thread locker to.

 

[newbury]

I like using medium strength thread locker for just those two reasons. I will NEVER use any sort of lock washer on anything that I can apply thread locker to.

YUP
Helical Spring Washers

Lock washers are good for those that sell lock washers.

Is a lock washer an effective torque retention device? - Mechanical engineering other topics FAQ - Eng-Tips

But if you don't want to believe me, perhaps you would believe NASA.

Quote:
NASA Fastener Design Manual RP-1228:

"The lockwasher serves as a spring while the bolt is being tightened. However, the washer is normally flat by the time the bolt is fully torqued. At this time it is equivalent to a solid flat washer, and its locking ability is nonexistent. In summary, a lockwasher of this type is useless for locking."

Or the US Navy.

Quote:
Naval Ships' Technical Manual, Chapter 75:
"Although lockwashers may be encountered, using the flat washers with selflocking nuts, self-locking fasteners, self-locking inserts, or thread sealants such as MIL-S-22473 anaerobic compounds is preferable.

 

[Deere Dude]

YUP
Helical Spring Washers

Lock washers are good for those that sell lock washers.

Is a lock washer an effective torque retention device? - Mechanical engineering other topics FAQ - Eng-Tips

Interesting. Maybe I'll use all three. Use a lockwasher and Lok-tite on the part of the bolt that the nut tightens to and never-seize the portion of bolt that is hanging out, just in case, and I probably never will take them off again, ..
The bolts I took off that had the lockwasher came off as expected for about three turns until it hit the bolt stud that was not covered and in the elements. Then everything ground up.

 

[EddieWalker]

I use blue Loctite on everything that requires torqueing down and for a lot of other things that I just don't want coming apart. I also use lock washers all the time, but after reading the information about them, I'm going to have to rethink that. Might be a smarter investment to go with crown nuts or whatever those nuts with the plastic ends on them are called.

Eddie

 

[newbury]

Interesting. Maybe I'll use all three. Use a lockwasher and Lok-tite on the part of the bolt that the nut tightens to and never-seize the portion of bolt that is hanging out, just in case, and I probably never will take them off again, ..
The bolts I took off that had the lockwasher came off as expected for about three turns until it hit the bolt stud that was not covered and in the elements. Then everything ground up.

To decipher the chart - a nut WITH a lock washer does WORSE than the nut alone. As Eddie wrote a nylon locknut is better McMaster-Carr

 

[mikehaugen]

The only thing bad about nylon locknuts is that you need to use 2 wrenches for the entire length that the nut is threaded on. Not a big deal if the bolts are the right length, but when does that happen?