Safety measures (7) A doubtful GV10
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AT A RECENT MoT roadside check I saw a GV9 issued for excessively loose half shafts—the flange joints had disappeared and the wheel discs were well oil-spattered.
Within the hour a service vehicle and fitter arrived to deal with the defect, and the vehicle was able to return to the checkpoint for a GV 10 clearance which was issued. However, my point is that the rectification work was of little real value.
The instruction, "tighten axle shaft nuts" is frequently noted on inspection reports and all too often is taken exactly as read by the fitter or mechanic concerned—he faithfully pushes his socket and brace on to each nut and tightens fully as instructed.
Yet in many instances the mechanic will fail to note the amount of stud protruding through certain of the nuts, and he will leave the job satisfied that all is well. In actual fact, in a matter of a few hours, those same nuts will again be slack and working, and if he returned to the job he would find that further tightening would only produce a further amount of thread— or he would reach the end of the outer threaded portion of the stud.
The answer is simple enough: the stud itself is moving out of the hub and if neglected this same stud will either come right out, or strip its own, or the hub threads, causing further delay. With slack studs the kick of the driven axle shaft will speedily enlarge its own stud holes and wreck the stud root area.
Therefore, on noting that three or more threads are protruding through nuts on these studs, the only answer is to take out each stud, remove the axle shaft, remove the threadbound nut from each stud, then refit each stud solidly home to its inner shoulder.
Quite a number of these studs have rather short shoulders and the stud extractor cannot be applied without damage to the threads, so it may be necessary to use the double-nut method to send them fully home. This problem of moving studs is noted around many parts of a vehicle where load or stress is in being—diff casings, gearbox rear housings, etc. In most instances the actual stud will be well out of its bed or root and will be on the move together with the unit or section it is supposed to hold secure.
The real reason for many of these halfdone nip-ups, does, I am afraid, hinge around the time factor, load and unload deadlines, large defect lists and limited time to deal with them, and so on. Yet those responsible are saving little in the long run, as this type of neglect, or repeated and temporary nip-up, will only result in a real stoppage later.
I should add that MoT inspectors are well versed in both good and bad engineering practices, and rarely will this poor example of vehicle repair be allowed to slip through.