Re. Seized / Sheared / Broken Wheel Nuts / Capped Wheel Nuts
I've just been though this nightmare scenario (2023). I had an MOT and just needed two new rear tyres. Garage couldn't get the wheels nuts off, and sheared-off 3 nuts whilst they tried to remove them!
Thanks to everyone who's posted tips and videos (not all on this forum). Here's a summary of what I've learnt. I hope it will help you. Once I had the right tools it was suprisingly easy to resolve.
My Jag is a 2012 XF with 20" wheels. (Check the correct torque, and you might need to experiment socket sizes for your car, but the principle technique is the same) :
Capped wheel nuts should NEVER be loosened or tightened with an air impact wrench. A hand driven torque wrench MUST be used. Tighten to approx. 125 N⋅m / 92.2 ft-lb (less if copper grease is used to prevent future seizing)
The capped (soft metal) nut is 19mm
The steel nut under the cap is 11/16”
A 17mm (undersized) twist socket (spiral profile) can be used to remove the steel nut under the cap if it’s frozen. The nut will be ruined after using this, so make sure you've got replacements ready.
If the steel nut shears off, a '20mm Starrett FCH2532 Multi-Material Fast Cut Holesaw' (the yellow one) + 'Starrett Hex Shank A1 Arbor 8.75mm' (to attach the saw to your drill) can be used to drill off the remainder of the nut, after which the wheel can easily be removed and the remaining part of the nut left on the stud then easily comes off using Mole Grips. I had to be brave to start sawing my car (!) , but this really does work. The youtube videos are truthful. Saw until you hit the washer and then you'll be able to get the wheel off. I was worried the remaining bits of the nut left on the stud bolt would be difficult to remove - they weren't.
The above is a much quicker and easier solution than trying to weld a nut onto a sheared nut, or drilling the nut to break it apart.
It took about 5 mins per nut to saw, and then twist-off the remaining bits from the stud.
The locking nut is less prone to the shearing problem as it's not capped in the same way. A locking nut extraction socket bashed onto the whole nut seems to be the way. None of my locking nuts sheared.
When choosing replacement nuts, solid ones mentioned elsewhere on this forum (and others) are popular. I went with genuine orginal spec. parts from Berkshire Jags. I will be careful to remind when servicing that they should only be tighted by hand torque wrench.
It seems there are a lot of manufacturers using capped nuts. Jags aren't the only vehicles suffering from this. I'm suprised garages aren't more prepared / informed to deal with this scenario.
Check your nuts!
