This is w.r.t. my friend's 2012 Chevy Sonic. We were doing a seasonal tire changeover yesterday. The lug nuts on the rear wheels were very tight, but did come off with some persuasion from my corded electric impact wrench. The threads were rusty, and I cleaned them up with a wire brush on my drill. Torqued them to 100 lb-ft per the owner's manual. So far so good.
However, we could not budge the lug nuts on the front wheels. (Well, of course we could have with a long enough piece of pipe slipped over the end of a breaker bar, but I was afraid of twisting off the studs.) I squirted them liberally with penetrating oil, and sent the spray can home with my friend. He did several more applications yesterday and this morning, and came over this afternoon to try again.
Got them all eventually, though on most of them I had to hammer away with the impact for quite a while.
But anyway, in every case the studs were wet with penetrating oil. I've read here many times that lubed threads call for 20% less torque - so I torqued the front-wheel lug nuts to only 80 lb-ft.
Did I do this right? Is it valid to consider penetrating oil a friction-reducing lubricant? When he comes back in a few days for me to retorque the lug nuts, should I bump them up to 100#?
Thanks!
However, we could not budge the lug nuts on the front wheels. (Well, of course we could have with a long enough piece of pipe slipped over the end of a breaker bar, but I was afraid of twisting off the studs.) I squirted them liberally with penetrating oil, and sent the spray can home with my friend. He did several more applications yesterday and this morning, and came over this afternoon to try again.
Got them all eventually, though on most of them I had to hammer away with the impact for quite a while.
But anyway, in every case the studs were wet with penetrating oil. I've read here many times that lubed threads call for 20% less torque - so I torqued the front-wheel lug nuts to only 80 lb-ft.
Did I do this right? Is it valid to consider penetrating oil a friction-reducing lubricant? When he comes back in a few days for me to retorque the lug nuts, should I bump them up to 100#?
Thanks!