A Basic System of Fleet
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4 a intenance rhis, the Second of Three 4rticles, continued from September 20 Issue, Out'ines a Suitable Organzation for Routine Main'enance Operations and Inspections and Overhauls. I Degree of Specialization
is Advocated By H. R. Morgan
T is usually found thin in the carrying out of routine 'maintenance operations, a form of "limited" specialization is to be advocated. Quite apart ;from the fact that when one man, oi a number of men, is occupied more or less continually upon one operation the team becomes more rapid -and efficient, and there is the decided advantage that the repairs and adjustments concerned are of a standard more closely The counterpart of each other than would be the case if they were carried out this week by one mechanic and next ;week by another.
have said "limited specialization is to be advocated." by which I mean that the specialization Should be limited in period, 'and that a change around between operatives and jobs should be made at prearranged pariods—Tierhaps at sixmonthly intervals.
For one reas-tm, the iola is made a little more interesting for the operatives. More important from the management point of view is that, in due course, all the men concerned became adept at most of the operation.
Responsibility for Records It is not proposed 'to go into such matters as the number of men required to handle this or that operation. For one reason, the size of the fleet and local conditions will be the determining factors upon that score, but the point that it is desired to make is that one man should be made responsible for the recording of each operation upon the relevant sheet provided for that purpose.
Again using the same example—the inspection and adjustment of clutches—the man responsible is called upon to inspect and adjust all clutches—so many each night or day— and to enter on the record sheet, opposite the vehicle number, the date on which the adjustment was carried out, together with the result of the inspection.
It is usually possible for an experienced fitter to judge the condition of affairs within the clutch, such as the thickness of the facings, etc., although possibly he may not be able to see inside. Failing other indications such as the square locating .pegs as on Leyland vehicles, the amount of adjustment taken up at the toggles is quite a reliable pointer.
Any such system of notation as that of the "star" or " asterisk " method can be adopted for recording the condition on the sheet. For instance, one star or asterisk can signify that the clutch is approaching, but has not yet reached, refacing condition. Two stars can mean that it is needing early attention and should be treated at the first opportunity, whilst three stars,-or asterisks, signify that It is in such condition that it needs refacing at once.
A method such as this enables the garage foreman, and the man responsible for the care of clutches, to make a reasonable forecast of the next day's (or night'e) work, or, for that matter, the next two or three days' work, upon that particular branch of running maintenance.
The same method of recording can be .applied to most other running maintenance operations; "top tuning of engines," "the inspection and adjustment of 'brakes," -and so on. When used with reference to brakes, The star or asterisk notation can have approximately the same meanings as When applied to clutches, but with the additional abbreviation to denote to which wheel the marking refersOfS/F—off-eide front, and .so on.
• Brake .Adjustment to a Standard
By the way, the inspection -of -leteikes shoved always include a test 'of .servos, -etc, and .it iS a good -idea to have a recoee. nixed standard to Which all brakes are -adjusted. So many teeth up the hand-brake quadrant, or o pedal 'depression of a certain amount, without servo assistance.
-Indeed, the adoption of a standard for adjustment is very necessary when :drivers are called upon to change from vehicle to vehicle eeveealetimes during one day, as -they often are in the vase of short-service passenger vehicles.
There is no need further to ,elaborate upon this method. as the application to most other operations of running maintenance will be patent to the practical fleet engineer. 3 -would stress, however, the rather urgent need carefully to supervise each section of the system during incipiency, to ensure that the principle is fully understood by all involved, and, therefore, is being 'faithfully interpreted. Also that the original estimate of mileage interval allotted is expedient from all points of view. ;
The foregoing has dealt with the running-maintenance section of the system. Intentionally, it has refrained from setting out all the operations considered expedient, as they are so universally recognized and accepted, that it would be a •waateof time and space to do so.
if it be discovered That, as a result of the system, components are sometimes being dismantled before they need be, it does not necessarily mean that the system is at fault. Investigation will, in all probability, prove it to be due to 'lark of understanding of the principle, inexperience of the operative, or poor supervision. The remedy will be apparent from the cause.
Next we come to Section 2—dock or sub-overhaul. Here, again, the mileage interval between operations is a matter for the individual fleet engineer. Obviously, a fleet of shortservice passenger vehicles, that stop and start every couple of hundred yards or so, day in and day out, will call for a shorter mileage interval between operations than will a fleet of long-distance coaches, running at even speed in top gear for the greater part of their mileage.
The necessity of a major overhaul can, quite reasonably, vary between 60,000 and 100,000 miles, and the engineer is in a much better position to fix this interval than myself, or anyone else. He knows the peculiarities of the job that his vehicles are being called upon to carry out, and the rate of mechanical dilapidation that ensues from those conditions.
Anyway, let us suppose that the interval between major overhauls is fixed at 75,000 miles, then sub-overhauls should take place at 25,000 and 50,000 miles. In other words, there should be at least two subs between major overhauls.
Separate Sub-overhauls from Maintenance
Experience of operation again prompts me to be a little emphatic that these interim subs should not be a part of running maintenance, but rather an integral part of overhaul maintenance. By this I mean that, wherever practicable, the operation should be carried out away from the service garage.
The vehicle concerned should be definitely reckoned as out of service for the period of the overhaul, and not made available daily or nightly, as is sometimes attempted when the job is carried out at the service garage.
When the latter procedure is followed, either much time is wasted dismantling and reassembling parts or components more than once, or a rush job is made of an important repair or adjustment that should be given more careful attention. The repercussion of this hurried adjustment is, at best, another " go " at the job at a later date by the running maintenance staff, or, at worst, a breakdown on the road.
The sub-overhaul is a periodic operation by adjustment or, if necessary, replacement, to correct incipient wear between major overhauls. If this is to be the case, then, obviously the inspection must be thorough and comprehensive. Everything must be checked, from chassis bolts to main bearings, not necessarily by stripping out. There are always ways of and means for checking the approximate condition of affairs within most components with the minimum of dismantling.
The inspection and overhaul should be sectionalized and a routine followed. The record sheet should have provision for each section to be reported upon—defect discovered, and
repair or adjustment effected. Sheets after the style of "Specimen 3" can be used, and a "file" copy made after completion.
The man responsible will be called upon to carry out and record the overhaul. The number of men employed, and the time allowed for the operation will be determined by the average weekly mileage of the vehicle, and the number of machines in the fleet. For example, if there be 100 vehicles in the fleet and the average weekly mileage be 800, then, if each vehicle is to receive a sub-overhaul at 25,000-mile periods, the fleet will take approximately 32 weeks to cover. Allowing six working days per week, this means that the time to be allowed for each vehicle will be two days, if the percentage of spare vehicles allowed will permit of one only to be tackled at once. If it will permit of two at one time, then it follows that each can occupy four working days.
Major Overhauls Must Be Thorough
The major overhaul section of the system is, naturally, of great importance, as the rest is foredoomed to failure if this major overhaul be not a first-class operation. Thoroughness and expert workmanship are essential, as is also the strict maintenance of schedule—irrespective of matters external to the system that endeavour to obtrude. I have watched major overhaul systems come seriously unstuck on more than one occasion because of a few vehicle accidents or untoward major breakdowns.
Wherever practicable, provision should be made for the possible intrusion of these untoward occurrences; if no other way be possible, work shifts on overtime should be introduced.