Was going over the bike checking for loose bolts and one axle pinch bolt gave away at first effort. SOB broke off way down in the hole, luckily an easy-out took it right out. Removed the rest and one other was stretched also. Replaced all four w/ 10.9 bolts (had to add a small washer because shoulder was larger).
Yep, consider yourself lucky as i have seen many stripped. I for one will never use a torque wrench on small bolts. To many variables and i have seen a lot of snapped bolts. Get a feel for the right tension and go with that IMHO.
Just a bit past finger tight. I learned this the hard way not long ago... Snapped the head off a pinch bolt. Took it to a friend who has all kinds of tools, etc. Couldn't easy out it. He was drilling on it and overshot. Gloop, gloop, out comes the fork oil (stupid design for pinch bolts, I see Husky finally changed this). Patched it with JB Weld and drilled out one larger size.
I could see these stripping out easy. If you look at the pic you can see only the bottom third of the bolt is engaging thread. Stock bolts are 25mm long but 30mm with about 1/16" cut off would work and grab a lot more thread. If you don't have an easy-out you can drill a shallow hole a little smaller than a flat blade jewelers screwdriver, tap the screwdriver in, and turn the bolt out. Sometimes this works better than an easy-out. .
Your worst enemy on these small 8mm head bolts will be to use a regular size ratchet when tightening. Just too easy to overtorque them with leverage of a 6"-8" handle. I use a shorty 1/4" drive ratchet 4" long and only hold it and tighten with my fingertips, not grip with my whole hand and palm. This works great for me as I always have a tendency to overtighten. _
DITTO. My partner calls me "Miss Snap-Off." I now use a screwdriver handle-type 1/4-inch drive to keep the torque down on the 8mm bolts.
Why not use a torque wrench? If there is a specific torque spec you should be fine. I've never twisted a bolt off using the correct spec, but maybe this particular application is different?
Because there are way to many variables especially on real small bolts. Did you lube the bolt? is it perfectly clean? Is it dry? Are both the both threads and mating hole threads perfectly clean and in good shape? I find it far EZer to get a feel for it by hand. I have read countless threads and talked to lots of people who snapped off small bolts trying to get to factory specs. Half the time they lubed the bolt or it was lube before and you can get WAY over the torque spec and snap bolts when lubed. Lots of bolts on dirt bikes get grit on them and then we blast them with WD40 to get them clean and to thread into the hole nice, then the torque specs are out the window. I only torque big bolts and only then when it might be important like a flywheel bolt or something. My opinion only.
Understood and you're right on the money. I'm a bit anal when it comes to maintenance and I always clean and dry bolts (non chlorinated cleaners) and I'll use an anti-seize product on any fasteners that are of dissimilar metals to the part they're threading into so maybe under those conditions I get good results. Most of the guys I know don't own a torque wrench and I'll cringe when they tell me they didn't torque head bolts or suspension fasteners, etc. I'm always waiting for parts to start flying off their bikes!
I just use a small box/open end wrench and get it good and snug; never had a pinch bolt come loose. Or any thing else, for that matter. I think you get a good feel for what "tight" is with experience. I do use a torque wrench for critical items on the engine, frame, fork pinch bolts, etc. One exception: the bar end bolts on my hand guards. Those tend to loosen and need to be checked often. Had one fall out on the trail last year, but luckily a riding partner had some spare bolts, and one of them fit. Lots of vibes on singles.
This is typically a bad idea when using a torque wrench and you will get it way tighter than it should be in my experience. Torque specs are for dry clean threads. Event the bolt grade and plating greatly effect torque as the bolt actually stretches a few thousandths and this causes the clamping force. Different grades of bolts with stretch differently. If you swap out the bolts that came with it for other bolts your torque spec is out the window. This is why for me personally I do it by feel on small fasteners, just to many variables. On pinch bolts they should not come loose as they are under constant tension.
There was a chaser on the crew named Thor (really) who used to strip the nuts that held the bar on his saw. Until finally one day the owner had the idea of cutting the handle off his bar wrench so it was only 2" long and giving him a screw driver to adjust his chain. Worked great, he still got them tight without breaking anything. I think lubrication on the threads is normally the main reason for breaking bolts while installing them. To cut down on corrosion so they don't break during removal anti seize is a really good idea in some cases-IMO. Reducing the torque by 30% for anti seize has worked for me.
A friend who is a car chief on an Indy Car team also cuts all the rachet handles in half of a new crew members if he has any in his box that are over 1/4" drive... Not fun pullin a motor to change a fuel cell cause the "new guy" overtightened the hardware.
