Thread: Nuts and Bolts - Torque ratings

I have had to change the bolts over on my ‘A’ frame - suspension link upper (pivot bracket) because after fitting a new exhaust it was too close the the bolt ends (nut end) and when the rear load space was loaded up it kept on banging against it.

I just swopped around the bolts to enter from the exhaust side.

My question is this, my workshop manual for my vehicle Defender 110 300TDI (1998) says these need to be tightened to 176Nm (130lbf/ft) but all the information I can find about these bolts (part number 253952) 1/2” UNF 6.25” is a grade 8 tensile bolts which only has an assembly rating of 141Nm.

Does anyone know if the manual is misprinted or should I be looking for a different rated bolt to reach 176Nm? I did find a US bolt company who said their bolts could get 120lbf/ft from a plain type bolt.

The original bolts started to spin when I was torquing past 140Nm. So I am getting new ones tomorrow this time with a nylon nut.

Originally Posted by chrisbbarnes

.....

Does anyone know if the manual is misprinted or should I be looking for a different rated bolt to reach 176Nm? I did find a US bolt company who said their bolts could get 120lbf/ft from a plain type bolt.

.....

Shouldn't be misprinted.
That 175Nm figure is very common for suspension bushes torque values in LR vehicles based on this chassis design.

Are you getting these US company bolts, or new bolts from LR parts seller?
If you are getting them from this US company, then I'd say don't.
LR probably specify their values based on their bolts and the requirements for the application too.

Other bolt companies will have varying max torque values for their fixtures too.

eg. Grade 8 3/4 UNF from Hobson is recommended to 492Nm

SEE CHART

But of course you wouldn't go that hard if used on your Defer, as LR specify their values for more than one reason.

Get the LR bolts, stick to the torque values specced in the manual