Torque is based on the size of the threads and not the size or type of screw head. The threads are M8 whether it's a hex cap screw or a hex socket screw, so 34-39 nm sounds about right. Make sure to grease the bolt threads but do NOT grease the axle tapers.
__________________
What, Me Worry? - Alfred E. Neuman
I'd like to think i have as much money as brains.
I see the light at the end of the tunnel, but the tunnel keeps getting longer - me