Trouble fitting rear brake caliper.

I took the rear brake caliper off my K3 650S at the weekend, when refetting the rear brake caliper and torquing up the caliper mounting bolt it sheared... I ordered a replacement mounting bolt which arrived today and I'm currently trying to fit it. I've got the torque wrench set to 23NM (as per manual) but it feels like it's going way beyond that (pretty much how it felt just before I sheared the first bolt), is there something else going on here or is it just me? I've just torqued the other bolt on the rear caliper to 27NM (as per manual) and that was fine, and felt easier too...

It didn't feel like there was much warning when the bolt sheared before, it felt like it was always on the brink of being correctly torqued, kept turning and turning and then it sheared. Kinda feels like it's going to happen again with this new bolt.

Additional info - I've applied copper grease to the bolt, would this make any difference?

[jambo]

Using a torque wrench what you're measuring is resistance to turning rather than bolt strectch or degrees of rotation. It's convenient, but the resistance to turning will be affected by grease or corrosion etc.

First off check the torque wrench is working well. Attach it to something that is't going to move and get a feel of when it clicks. Some torque wrenches have a reverse setting by taking the drive out and fitting it in the other way meaning you'd never get it to click if it'd been left like that.

23Nm is a fairly standard good firm tug on a 3/8" drive socket, if it feels like you're straining, for the love of God stop.

Jambo

I did that by torquing the other bolt (can't remember it's name... the one that's torqued to 27NM), to 23NM to get a feel for it, and you're right, it's pretty much just a firm tug... I'd be tempted to leave it at the stage of 'firm tug' but I want to make sure there's nothing else going on, plus it's nice to have the confirmation from the torque wrench that it's torqued correctly.

Took the bolt back out, inspected the threads and they hadn't stretched, phew, cleaned some of the grease up and reinserted, felt a bit better but still felt like it was going beyond the desired torque... backed off a bit and did up to 'firm tug' after getting a bit more of a feel by torquing other bolts.

I hope it's okay...

The calliper is aluminium cast, it doesn't take much to shear
If you don't trust the setting on the torque wrench, then go by the feel of it.
Once it's snug, go for a ride and check it again when you get back.
Once the bolt is tighten to a certain limit, it would take an equal amount of torque in the opposite direction to undo it ... which isn't a day to day occurrence unless your wheel is getting stolen

That is how I'm going to leave it for now, should think it would be okay, just a bit weird that that particular bolt didn't feel it was torquing properly.

[Bibio]

as long as its tight and wont move. to much coppaslip. i use a toothbrush and brush a little on one side of the threads only as when you screw it in it distributes to the rest of the threads.

i've had more problems use torque wrenches that anything, i trust my own built in one.

Lesson learnt.