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Snapping off lug bolts...

Metal Twister

Metal Twister

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Anyone else having issues with lug bolts snapping off?
I have a 78 Blazer and the rear lug bolts keep snapping off. I lost one to the inpact wrench while loosening, one while tightening by hand, and on last desert trip I almost made it home when I heard 2 rattling inside my wheel cover. Im not sure why Im brealing them off. Is this a common thing for the 12 bolt rearend? I swapped out axles yesterday but now Im thinking pressing out the old ones and drilling out the old holes to install larger lugs and use them for the spares. Any advise other than checking the torque values? :eek1: :dunno:
 
What type of lug nut and wheel are you using? How tight are you tightening them to?
 
Metal Twister said:
Anyone else having issues with lug bolts snapping off?
I have a 78 Blazer and the rear lug bolts keep snapping off. I lost one to the inpact wrench while loosening, one while tightening by hand, and on last desert trip I almost made it home when I heard 2 rattling inside my wheel cover. Im not sure why Im brealing them off. Is this a common thing for the 12 bolt rearend? I swapped out axles yesterday but now Im thinking pressing out the old ones and drilling out the old holes to install larger lugs and use them for the spares. Any advise other than checking the torque values? :eek1: :dunno:
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I was breaking off at least one every trip when I had 7/16" lugs, then I drilled them out to 1/2" and never had one break afterwards.
I had 35" tires on them and I was wheeling it hard on rocks.
 
imiceman44 said:
I was breaking off at least one every trip when I had 7/16" lugs, then I drilled them out to 1/2" and never had one break afterwards.
I had 35" tires on them and I was wheeling it hard on rocks.
Click to expand...

Same here, 7/16" lugs torqued to 75lbs. Im running 35's AT's on Weld wheels with a little offset on them. Ive been wheeling it hard as of late so on cobble and rocky washes, maybe that is the problem / answer. 1/2 Inch'ers it is. :waytogo:
 
bp71k5 said:
75 lbs sounds too tight for a 7/16" stud. Is that really the torque spec?
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I was going to say something, I think 35-45 is plenty, I don't even torque mine anymore, just use the star wrench and I can feel the right torque.:whistle:
 
bp71k5 said:
75 lbs sounds too tight for a 7/16" stud. Is that really the torque spec?
Click to expand...

75 lbs. is the proper torque spec for a 7/16" stud. A 1/2" stud would be 85 lbs and the 9/16" studs are 115 lbs.
 
If the studs are grade 8 or better, than 75 is pretty close to the recommended maximum torque for other grade 8 fasteners. When I had a 12 bolt, I could feel the nuts being overtightened just using my lug wrench. I never used a torque wrench on them, but I doubt I was getting them anywhere past 75. I guess I'd back off the torque or get bigger studs like it sounded you decided on.

Edit: my factory manual says 55-75 for the k10 series on my 71. If they are snapping then maybe the torque wrench is off and you are getting them tighter than that range. Or if you installed the studs by using a lug nut to draw them in and seat them, I've read that can cause extra stress on them and lead to wheels falling off. I've never had one fall off so I can't verify that info.
 
bp71k5 said:
If the studs are grade 8 or better, than 75 is pretty close to the recommended maximum torque for other grade 8 fasteners. When I had a 12 bolt, I could feel the nuts being overtightened just using my lug wrench. I never used a torque wrench on them, but I doubt I was getting them anywhere past 75. I guess I'd back off the torque or get bigger studs like it sounded you decided on.

Edit: my factory manual says 55-75 for the k10 series on my 71. If they are snapping then maybe the torque wrench is off and you are getting them tighter than that range. Or if you installed the studs by using a lug nut to draw them in and seat them, I've read that can cause extra stress on them and lead to wheels falling off. I've never had one fall off so I can't verify that info.
Click to expand...

There old... Maybe its time to just change them anyway. Im getting gun shy and starting to think my wheels
ARE GOING TO FALL OFF ALL THE TIME! In this case bigger is truly better. :D Thanks guys:waytogo:
 
Wait, on my 94, stock spec was 120 ft/lbs. 130 on newer ones.

I've always put 120 on my 8lug burb, is that way too tight? Never snapped a stud....
 
dhcomp said:
Wait, on my 94, stock spec was 120 ft/lbs. 130 on newer ones.

I've always put 120 on my 8lug burb, is that way too tight? Never snapped a stud....
Click to expand...

You have 8 lug and that means bigger lugs either 1/2" for earlier ones or 9/16" for the later ones like yours, obviously it would require more torque.:waytogo:
 
imiceman44 said:
You have 8 lug and that means bigger lugs either 1/2" for earlier ones or 9/16" for the later ones like yours, obviously it would require more torque.:waytogo:
Click to expand...

Ok, cool. And the newer IFS stuff has larger lugs?
 
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