Archiddeon wrote: I'm trying to get the cap off the side of my GPZ 550 engine to hand turn the crank and see how the pistons feel, but the Allen-type hex bolts are proving stubborn. Got them hosed down with some PB Blaster, but wondering what the best approach is to loosen them while minimising the risk of stripping/rounding the inside of the heads?
I suppose from worst to best would be Allen key - hex socket - impact wrench with impact hex socket? How would normal hex sockets versus the rounded-head ones compare?
Thanks!
I have two air impact guns, a 1/2" and 3/8", and they're cheapo's from Lowes, been using them for years now. Anyway, I've found that for smaller allen cap bolts the 3/8" gun works great with an allen socket set. A set of allen sockets isn't terribly expensive at all, Lowes, Home Depot stuff is adequate, or even Harbor Freight. Even when the bolt head is kinda galled, firm pressure against the fastener with the gun and the impact "shock" of the gun has really never failed me, except one time -- trying to get the allen plug off the left side of my DR650 Suzuki. But that's aluminum. I had to chisel that one out and purchase a new replacement. But for steel fasteners, pneumatics work best.
As for anti-seize, I buy the permatex brand in the bottle with the brush. Lasts a long time too.
For really stubborn bolts of any sort, assuming there's no fire hazard, heating them a bit almost always helps. Aluminum and steel have different expansion rates when heated and plus, considering some of these really stubborn fasteners may have thread lock on them, it tends to soften that material a bit.