Hitch Bolts

[psford]

After removing the grade 5 bolts several times on the height adjustment on my fifth wheel hitch , and retightening them, thought it time to replace them with new ones. Would grade 8 be an overkill or just stay with grade 5. Have heard for certain applications you can actually get too hard of bolt. Any thoughts on this. Thanks

[psford]

Thanks for the replies, I will stay with grade 5 . Big reason for replacing is that every time I removed them I never torqued them with a torque wrench, and probably tightened them more then needed. Little confusing on the torque for 1/2-13 bolts ,I looked at about 6 different charts, and got anywhere from 57-78 ft lbs of torque dry for grade 5 bolts, I will go with 70

[dezl_dr]

Lock washers aren't really that good for a torqued connection. That's why they aren't on head bolts. Grade 5 bolts and hardware is fine. If you want to make sure they stay tight a little blue loctite will do that.

I think the grade 5 vs 8 is cost. A tractor trailer doesn't use grade 5 to hold the fifth wheel on. Clamping the steel plates together so tight they can't slip is what holds the hitch. Now if it's a shear like a reese hitch receiver pin with some slop in it, that I think is correct for a softer pin.

I'm no engineer, I know a couple if you want me to ask?

[TNRIVERSIDE]

Like others I would stay with Grade 5. When replacing critical components be aware that there are counterfeit bolts out here. I would stay with the original parts if possible. If you do replace buy from a good source.

[cummins2014]

BTPO1 wrote:

jamway wrote:
If you have not torqued the bolts to a destructive torque there is no reason to replace them.

You may want to think about replacing the lock washers if they have been used several times. You would want to get grade 5 lock washers. JMO

My hitch came with just the locking nylon nuts, probably would not be a bad idea to add lock washers.

[Goostoff]

copeland343 wrote:
Grade 8 will sheer while grade 5 will bend giving you time to replace. When grade 8 goes it is gone. Stay with grade 5 in this application. Replace the grade 5 lock washers.

Grade 8 is better in applications where straight line pull force is on them. Grade 5 is better where there is sideways sheer force on them just like stated above. Stick with Grade 5. The engineers have all sorts of information at their fingertips to help them determine what bolts are in there. Dont question what is in there if you dont have that info as well.

For what it is worth I am usually the first one to bash engineers for stupid decisions on designs and stuff. In this case there are charts that they go by for yield strength.

[Cummins12V98]

IMHO 8

[copeland343]

Grade 8 will sheer while grade 5 will bend giving you time to replace. When grade 8 goes it is gone. Stay with grade 5 in this application. Replace the grade 5 lock washers.

[BTPO1]

jamway wrote:
If you have not torqued the bolts to a destructive torque there is no reason to replace them.

You may want to think about replacing the lock washers if they have been used several times. You would want to get grade 5 lock washers. JMO

[jamway]

If you have not torqued the bolts to a destructive torque there is no reason to replace them.