MAINTENANCE Behind the News
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AN increase of 75 per cent. in ' the annual vehicle mileage in the four years since 1949 and a corresponding fleet strength increase of only 50 per cent, is the record of the transport department of the Birmingham Post and Mail, Ltd. In this period, the mileage has risen from 840,000 to. over 1,500,000 and the number of vehicles from 67 to 100.
Traffic has progressively become more congested and consequently each of the vehicles in the present fleet virtually does much more work per mile than before in completing up to 1,000 miles in the week. Nevertheless, the fleet's average fuel consumption rate of 25.8 m.p.g. shows a reduction of about 10 per cent., and the saving on man-hours per vehiclemile expended on maintenance is nearly 20 per cent. Comparisons with pre-war figures indicate even greater gains, despite enforced changes in organization because of bomb damage.
Precise Comparisons
Mr. J. J. Jennings, the garage manager, does not subscribe to the view that the design of British light delivery vehicles and the standard of workmanship are deteriorating. He is qualified to make precise comparisons.
Charts in the transport office (some are 20 ft. long) show the mileage run and the time taken by each vehicle on the delivery of every edition to the nearest .I.-mile and i min., and workshop records provide an equally accurate indication of maintenance and overhaul work.
The full significance of these figures and comparisons can be appreciated only if they are reviewed against the background . of the operating schedules. The breakdown n16 of a vehicle on its way to one of the 10 branch offices, or upwards of 1,000 agents, in a radius of 60 miles would represent a loss which it would be impossible to make good.
Delayed news has no value and a few minutes on the age of a newspaper can be fatal to the purpose of the editorial staff and the business
P. A. C. Brockington, A.M.I.Mech.E.
management. Members of the transport department cannot, therefore, afford to leave anything to chance.
The fleet comprises 86 10-cwt. vans and 20 cars, the commercial vehicles including Austin A40, Commer, Morris-Commercial and Thames models. The policy of the department is based on the renewal of a van every five years, or after it has covered 100,000 miles, the object of the scheme being to avoid complete rebuilding. Many of the vehicles are, however, showing such good wearing properties that the limiting period and mileage may be extended.
As reported in the November 27, 1953, issue of The Commercial Motor, one A40 has covered over 100,000 miles without a rebore at a.n average fuel consumption rate of 32.7 m.p.g. Wellworthy Duaflex piston rings and new crankshaftjournal bearing shells are fitted at
intervals of rather more than 27,000 miles.
Cylinder-bore and crankpin measurements are made whenever the pistons are withdrawn, and they indicate that the majority of the vehicles should successfully complete a similar, or higher, mileage without reconditioning: All the operational and maintenance information given relates to the A40, which is taken as a representative example of the fleet.
If the promise of present experiments with chromium-plated rings fitted in the top piston .grooves is fully realized, it will be possible to extend the mileage life of the vehicles far beyond previous' expectations. According to Mr. Jennings, this practice can reduce wear in a given mileage to a quarter of the normal, and to make use of the rings' full potential, they may be fitted to new engines before the vehicles are used in service.
In the September quarter of 1953. the fleet mileage was 413,808, . The cost per vehicle-mile, including wages, rents, fuel, depreciation and other overheads was 13.13d., and excluding all wages the figure was 5.33d. The ear running costs are abnormally high because they include drivers' and mechanics' wages during lengthy stand-bys and delays when members of the editorial staff on urgent jobs are kept waiting.
Tyre costs average 0.094d. per mile per cover, worn covers being replaced by factory remoulds. Spare wheels are fitted with worn covers to discourage thefts. Pressures are checked weekly by two drivers detailed for the job. Although a regular change-round of the tyres is recognized as good practice, the exacting operational schedules do not allow sufficient time for this to be done. Records show the history of every cover.
Tyre Wear and I.F.S.
Normally there is little difference in the wear of tyres fitted to vans with independent front suspension and those on vehicles with beam axles. The former type of vehicle is capable of cornering at greater speeds and if this potential is abused the rate of tyre wear is consequently higher. It has been found that bursts on front tyres are usually caused by uneven brake action.
One of the measures which undoubtedly contributes to a long engine life is the practice of changing the sump oil at 750-mile intervals. when the vehicle is also inspected and greased. At 4,000 miles; a routine is done which includes changing all the transmission lubricants, washing and greasing the springs, lubricating the stub axles and oiling all small joints such as door handles. When the vehicle has covered 10,000 miles. the brake shoes are removed and the facings measured, after which braking performance is tested with a Tapley meter.
Unless the brakes are capable of a further 10,000 miles running, they are removed to avoid intermediate 'attention. As already stated, Duallex piston rings and new bearing shells are fitted after about 25,000 miles.
The grades of oil recommended by the manufacturers are employed, and upper-cylinder lubricant is added to the fuel throughout the life of the engine. This is purchased in bulk.
Another interesting cost .saving practice is reclaiming valves by refacing, which virtually obviates the purchase of new valves. Chromed rings are installed in engines after a rebore but are fitted only to worn
engines when the bore wear is 0.003 in., or less, because of the long bedding-in period (5,000 to 6,000 miles). Because of the many stops per mile, clutch and selector fork wear is relatively severe, the worn forks being rebuilt by oxy-acetylene welding, but little trouble is experienced with other parts of the gearbox or with back axles. Three rear axles have been overhauled in 1,600,000 vehicle-miles.
The average number of engines overhauled in a month is between .four and five and it is necessary in every case to complete the job between Monday and Friday to prepare for the sports-special rush on the Saturday, when, if possible, every vehicle in the fleet must be in service.
No Division of Labour
The total transport department staff numbers about 100, including 80 full-time drivers, 16 workshop personnel (some of whom also drive on Saturdays) and five executive and office staff. Of the 16 men in the workshops, two are employed permanently on greasing, three on painting, two on bodywork and two on electrical repairs. There is no division of labour in an emergency.
No mechanical or bodywork repairs are performed by outside concerns, except when a crankshaft or block is reground. The workshops are equipped with electric-arc and acetylene welding plants, a lathe, a drilling machine, and an alignment gauge, in addition to an engine stand and a comprehensive set of tools.