road and
Page 52
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workshop by Handymar
Benchwise: delayed risks
• Although at the time a rush job is carried out the repair may in fact work, sooner or later the malfitting of a part will bring about its own destruction or that of parts complementary to it.. And unfortunately the lapse of time between fitting and failure does not as a rule enable one to show the fault in its true light. All too often the vehicle will be a long way from base and there will be a danger that with new—and less concerned repairers—this same lack of thought, care, or knowledge will occur again.
My photograph this week shows a modern hydraulic pipe coupled to a clutch operating cylinder; the angle from which this picture was taken, ie below the chassis, is also the angle at which the mechanic would see the pipe as he fitted it. On a motive unit this is by no means an easy position in which to work, as frequently a difficulty occurs in seeing what you are doing because your hands are in the way, so there can be some little excuse.
Lazy clutch However, on the vehicle in question there had been regular reports of lazy clutch operation from certain drivers familiar with air /hydraulic assisted clutches; there was no report made by a driver who had recently been driving straight mechanical, nonassisted clutch vehicles. Thus the fault was in evidence for some little time until it worsened enough to become really troublesome.
Investigation finally brought to light the fact that the pipe was badly laid out and was in fact turned quite sharply around a metal air pipe and was then compelled--almost by means of a kink—to line up with the cylinder. This was bad enough, but the action of operating the clutch pedal caused the pipe to attempt to straighten out, and the photo shows th imprint on the flex pipe, and this load ha the effect of sharpening the angle of th elbow and in turn reduced the o movement.
The pipe also had an internal stoppage this was discovered on removal as there wa no road through it in one direction. It wa later cut open and the inner lining wa found to be ruptured and turned back insid the pipe: constant movement against th metal pipe had caused the lining to fractur( pressure having driven the torn fabri further in the direction of the hydrauli cylinder.
Flex pipes While in • this instance there was n serious aftermath to this ill-fitted pipe, does indicate that the mechanic was tie aware of the danger caused by a sharp tur and contact with other vehicle parts; 11 may not have realized that flex pipes und( pressure will attempt to straighten out, an must be given leeway to do so.
Another feature of pipe fitting, especiall in confined spaces, is that once a pipe reasonably lined up among the nearb chassis items and screwed securely home 1 the tied end, it is then pushed through tk bracket for the lock nut and it is this fin. task that may undo the good work. Tt mechanic may just be able to get one han in with his spanner to finally lock the pip and may not be aware that he is also puttir some part of a turn on the pipe, unless F is most careful to give a final check. It this part turn that may give the pipe crucial twist or kink unseen.
Where these situations are met, it pays I lock a spanner on the fixed hexagon at wedge it there if it is not possible to get hand to it; also a chalk line on the pii makes it easier to see if the pipe has turn< before locking up.