Trucks & Trailers - Grade of bolts
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05-31-2012, 06:47 AM
I have to replace some of the major load bearing bolts on a triple axel EZ Loader trailer. The current bolts are a grade 5 but 2 have sheared lately (4 years old). Would going to a grade 8 be a benifit? These bolts are subject to road bumps and vibration.
05-31-2012, 06:56 AM
get A325 bolts or F1554, and u will never have a problem
A325 bolts are good for 5/8" Diam = 7360#, take out about 1.5 for impact, u should be fine for 4900# of shear in each bolt
05-31-2012, 04:34 PM
Bolts often fail because they are overtorqued. If they actually "shearing" (getting cut in half) you have a very unusual problem. Find out why. Perhaps go to a larger diameter bolt with some kind of sleeve to spread out the point load.
06-04-2012, 11:41 AM
The steel being held by the bolt is probably not as strong as the bolt. It was probably overstressed by an air wrench.
I would doubt if you need a grade 8 or that they would add anything positive to the mix.
06-04-2012, 01:46 PM
some small air wrenches will put out 300 ft lbs.
car lugs nuts are typically 60-100.
but many shops love air wrenches