Loose wheel nuts
ATIDY, WELL-MAINTAINED Series III pick up came into the workshop for various jobs, which included investigating an odd intermittent clonk, which sounded as though it was coming from the front suspension. I took the vehicle for a drive and there was indeed a clonk, usually when turning left. It sounded suspensionrelated, but close inspection of the springs, shackles, U-bolts and shock absorbers failed to reveal anything amiss.
The road test threw up an issue that the owner had not mentioned, which was that the front brakes were pulling slightly to one side. I jacked up the front wheels, dropped the vehicle onto a pair of axle stands and set about removing the front wheels to gain access to the brake drums. The wheels were steel eight-spokes of the kind which I remember seeing on old Land Rovers back in the 1980s: when I was still at school and imagining what kind of Land Rover I would buy when I passed my driving test. Whatever model it was I was determined that it would have white eight-spokes, as they were quite fashionable back then, especially on the Fords.
The wheel nuts on the nearside were tight, very tight, and I was only just able to shift them with the impact gun. I moved round to the offside expecting more of the same, but all five nuts came undone with no effort at all. They were little more than finger-tight. I removed the wheel to be faced with two bright, shiny concentric rings on the face of the brake drum, and knew I had found the source of the clonk.
These eight-spoke wheels are of a type I have seen a couple of times before, where the rear face is not flat but dished, and when offered up contacts the wheel hub only at the inner and outer edges. The idea is that as the nuts are tightened the wheel centre flexes inwards, applying pressure against the nuts which stops them coming undone. This is all well and good provided the nuts are done up tight in the first place: on this vehicle that was not the case. The wheels also had oversized centre spigot holes and relied on the tapered seats of the five wheel nuts to centre them. With the nuts only done up finger-tight the wheel was able to move fractionally against the drum. It had worn a groove deep enough to make an audible clonk under load as the wheel shifted fractionally on the hub.
A long time ago I was driving an ancient Mini pick-up, fortunately not going very fast, when there was a rattling noise, a thump and one corner of the vehicle dropped slightly. I pulled up to find that one of the rear wheels had fallen off. Being a Mini on ten-inch wheels it didn’t have far to fall: I suspect the consequences for a Land Rover on 7.50 tyres would be rather more dramatic. Moral – check your wheel nuts regularly, and if your vehicle develops an unusual suspension-related noise, don’t wait for something to fall off before you find out what is causing it.