Thanks. Well today cost me £50. Father had spoken to someone who had done a few who said FT. So we started this morning by putting them on with the impact gun but on a low setting and not overly tight as we planned to then use a bar to tighten. At lunch I though I better check the torque from APH who supplied the bars and they said 100nm. Checked the 3 bars we had put on - up to 130nm. Phoned another mechanic who’s first words were 100nm and then take the bolts out and replace with new. Lesson learned get all the information before you start!Did rasp bar on MF 7256, no torque figure in workshop manual and originals not especially tight.
Had two options which was find torque figure for 8.8 bolts which were new and replaced with bar or make sure they are FT ( farmer tight etc).
Opted for latter as used impact gun to make up then breaker bar for 1/2” socket set to make sure tight.
Given that most standard spanner’s are the ideal length for a standard bolt torque, using the breaker bar to increase torque slightly was ok. Old man also shocked the bolt when tight before final checking to make sure not hung up on anything.
I am comfortable with this approach as did same for MF36 which then did 10 years with no issue.
Appreciate it is a NH but same principles apply, appreciate work involved removing trunk and piece of mind knowing bolts are correct torque gives but generally bolt torques for a given size should be material and lubricant dependant which many of the agricultural manuals fail to cover. Work in oil industry and difference in tension applied to a bolt with different or no lubricants applied is scary.