Author: John Hopwood
Most cars have four or five to keep the road wheels attached, we have to manage with a paltry three and little ones at that! I could criticise Austin for this design, but in reality the three brass nuts have stood the test of time with them all now being over 70 years old. However, if your wheel nuts are of this vintage (and I hope many will have been replaced by now) then it is time you took a good look at them – do it anyway.
I have been in the company of two A7 drivers, on European tours, who have experienced the symptoms of loose wheels, despite the wheel nuts being tight!
What happens over time is that the cone on the nut becomes distorted, allowing it to protrude through the wheel-centre, resulting in the nut 'bottoming' on the stud thread giving a false impression (because the nut is tight) that the wheel is being clamped properly onto the brake-drum / hub assembly.
It is essential that the cone on the nut makes adequate contact with the 'cup' in the wheel-centre before the nut 'bottoms' on the stud.
How to check this?
Take a wheel off and present each nut, by hand, to a 'cup' in the wheel-centre. There should be approx. 1/32 ins. from the end of the nut to the wheel surface, it must not be flush or protrude (see Pic. 1 below).
If this is not the case, then truncate the cone on the nut by filing, or better still by machining in a lathe as I have done (see Pic. 2 below).
It is essential, of course that the thread in the nut is in good condition. If in any doubt – replace – or better still get them Helicoiled.
Click on the thumbnails for a larger image.
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