[MickT]

Well sheared another wheel bolt the other trying to undo it, weird because I had taken wheel off only a couple of weeks ago, and actually only tightened the bolts back on to about 90nm (tyre fitter told me 93nm recently). Thats 2 bolts now in the space of 2/3 months, and has probably cost me £40-£60 to get sorted

I am assuming these bolts can become stressed over time, particularly if not tightened to the correct torque, so am considering replacing all the bolts now, do you think this is worthwhile, and if so where should I get bolts from i.e. from dealer or any other wheel supplier, am dubious about buying such things from ebay and the like. Also anyone know the correct size ? and do I need the bolts with washers on wobble bolts I think they call them ?, cheers

 

[Pomeo]

Thread is M12x 1.25

Pomeo

 

[aggy8888]

Has anyone else suffered wheel bolt problems with a 166? I believe under tightening of all bolts on a wheel is the only likely cause of failure. Bolts under tension are only subject to cyclic stress when the forces acting against them regularly exceed the torque value to which they are tightened. It is this cyclic stress that causes fatigue failure. Four correctly torqued bolts with the fifth sheared or broken should not in itself be a big problem. With two bolt failures it would be prudent to assume that others may fail due to a history of stress caused by extreme lateral forces exerted in cornering exceeding the wheel bolt torque. Should other owners have experienced similar failures we may all have a problem.

 

[niallmoran]

not aware of any issues....a wee dab of copper grease normally keeps mine from seizing up

 

[michelalfa]

Has anyone else suffered wheel bolt problems with a 166? I believe under tightening of all bolts on a wheel is the only likely cause of failure. Bolts under tension are only subject to cyclic stress when the forces acting against them regularly exceed the torque value to which they are tightened. It is this cyclic stress that causes fatigue failure. Four correctly torqued bolts with the fifth sheared or broken should not in itself be a big problem. With two bolt failures it would be prudent to assume that others may fail due to a history of stress caused by extreme lateral forces exerted in cornering exceeding the wheel bolt torque. Should other owners have experienced similar failures we may all have a problem.

yes, my 1999 166 has had this problem on both front wheels (190,000 and 220,000 km) with a two year interval, both times a few days after I had the wheels removed and refitted, I have to assume they were badly mounted, either gunned in without first finger positioning, or over/under tightened. In the second occasion, when I checked the wheel bolts, all five bolts sheared off, and I had to change the hub and the drive shaft. The tell tale sign is a knocking sound.

 

[MickT]

I have started using copper grease, but even so think I will swap all the bolts then ensure they are correctly tightened to the correct torque of 93nm.

 

[robcarrera32]

I have started using copper grease, but even so think I will swap all the bolts then ensure they are correctly tightened to the correct torque of 93nm.

Not sure grease is the answer. Would this affect the torque applied?
Also mine were very difficult to screw in finger tight until I cleaned out the dried grease from the threads.

 

[michelalfa]

I have started using copper grease, but even so think I will swap all the bolts then ensure they are correctly tightened to the correct torque of 93nm.

I was under the impression you should not be using grease on wheel bolts...

"nut and bolts are designed to be tightened up to a specific torque based on both contact surfaces being clean and dry.

The addition of any form of lubricant will reduce the friction and will decrease the torque at which point the nut bolt would be at the correct design torque. By still turning the torque wrench to achieve the designed reading the bolts or studs would stretch thereby weakening them."