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Does anyone know what class or grade the M12 cap head screws are that bolt the spindles to the hub on VR?

The screws have no markings and are NLA from Holden. Manual says not to be used more than 3 times. In doubt then replace.

Cheers.

hi vlad from memory there 12.9 grade.

Thanks. I had bought some plain black FKE branded one, but I am about to put an order through to Wurth so I might get some better quality ones just in case. I am also having my control arms and road safe ball joints machined for perfect flat friction joint and machined out for shanked M12 to pin the joint as well. The 8.8 M8 they come with are a joke!

Haha yeah those nuts and bolts that come with the joints,you can almost pull the nuts over the thread

there are 3 problems
1 not enough clamping force from those bolts.
2 uneven and un-machined flange surface, left as is from casting.
3 painted all over. Flanged surface should be bare as well as under the bolt heads.

All this contributes to the worst possible combo leading to failure.


I am having my machinist check the arm flange for flatness otherwise he will machine it. He will machine the flange of the ball joint as they rock around on the arm. Not flat at all

spot face both bolt head and nut area for perfectly square and flat fit. machine perfect size and straight holes for the shanked bolts to be effectively a snug fit to pin the ball joints as well as relying on the massive clamp force of 3 x M12 10.9 bolts and steel lock nuts. So these joins will take massive dynamic loads with no problems. It will be heaps stronger than even factory magna grip rivets.

I have fully rebuild frond end with superpro bushes and tops, boge sports shocks. slotted rotors with A1RM QFM pads and 235mm wide tyres.

I need strong stuff to take what I give it

vlad01 wrote:Does anyone know what class or grade the M12 cap head screws are that bolt the spindles to the hub on VR?
The screws have no markings and are NLA from Holden. Manual says not to be used more than 3 times. In doubt then replace.

Does the manual give a tightening procedure or torque figure for them?

yes. you do it in 3 stages i think?