Need Help Finding Torque Value New Pulley Bolts
 

Just finishing up the repair and replacement of Crankshaft Pulley on 1984 300D OM617 euro. Two pulley bolts were broken and had to order new ones. The new ones no longer have a shoulder and have a round head with Torx drive. The FSM only lists a M8 x 65mm bolt, and mine are 45mm. The torque value on the M8 x 65mm is 35 Nm. When I tried that I broke the first new bolt I torqued. Someone from UK had a FSM showing a M8 x 30mm pulley bolt with a torque value of 25 Nm. Does anyone have the factory torque value for this new bolt please, or know where I might find it.

Thanks
THammer

1) A bolt that is 20mm shorter than the original will have minimal thread engagement, if any. 65mm underhead length is correct for attaching the pulley(s) and dampner.

2) 35Nm is correct for M8 in steel. 35Nm = 25lb-ft

3) If there was minimal thread engagement, stripped threads would be a possibility, but torsionally breaking the bolt is unlikely.

Pics of the various pieces will be helpful.

The FSM has the incorrect bolt, M8 x 65mm. The correct bolt is Mb x 45mm. The problem is that since the FSM lists the wrong bolt I think it also lists the wrong torque. The classic center said they don't know the torque specs for the new bolts. I know it's not 35 Nm because they sheared off before reaching that torque. I am leaning towards the 25 Nm which is the spec for the M8 x 30mm bolt.

35 Nm worked for me. Maybe you got some low grade hardware or your wrench is out of caibration. Bolt length is not generally a factor in determining torque values.

Only if you want your crankshaft seal shredded.