Commercial Motor Magazine
December 1960

  Taken from the
Commercial Motor Magazine
December 1960

THE G.P.O., like other Government Departments, is not entirely free to determine how much it will spend on buying vehicles. Money spent on the purchase of all new vehicles, whether. required as additions to the fleet or as replacements for vehicles to be discharged, is regarded as capital expenditure and as such is indirectly controlled by the Treasury. The amount of capital which the Post Office can invest from year to year to renew and develop its services (of which the transport fleet is an essential part) is determined by Governmental decision on what the nation can afford from national resources for public investment as a whole.

Therefore, in addition to the many problems necessarily associated with the running of a fleet of some 42,000 vehicles and trailers, those in charge of the purchase, maintenance and operational cost control of the G.P.O. fleet have to cope with the extra problem of financial uncertainty; and it is to the credit of the G.P.O. Motor Transport Branch that they successfully follow a pennywise policy without falling from high standards of vehicle specification and care.

There is clearly reason for extensive standardization upon one make, and the acceptance so far as possible of productions with no or few modifications from normal.

When standard vans are suitable for G.P.O. service, they are purchased in complete form, but if the bodywork does not meet these requirements, chassis are obtained and contract awarded for the construction of bodywork to G.P.O. specification.

More than 1,000 Morris Minivans have been ordered and all but 50 will go into service with engineering side of the G.P.O., the operational activity of which were the subject of an article in The Commercial Motor. The remainder are to undertake postal duties, as described in the issue dated August 1959. These vehicles will supplement the predominant 5cwt. type, the Morris Minor van, an interesting featt of which is that the engine, although otherwise of the Series pattern, has a capacity of 803 c.c.

When the "A" Series 948 c.c. engine was introduced, it was considered that, not withstanding the advantages which might accrue to other users, the increase in engine size and power output compared with the previous unit will not be economical for G.P.O. work. It was therefore arranged that the cylinder blocks for G.P.O. vehicles this type would be bored out to the same dimensions as the former engine, which has been found quite satisfactory.  The G.P.O. buy 20m. gallons of petrol a year, and difference of 1 m.p.g. in consumption means 200,000 in financial terms, To this extent the manufacturers were able to meet the needs of the G.P.O. In the matter of rubber wings, however, the G.P.O. had to adjust to changes in design which made these components a less practical and more costly deviation from standard production than before. Rubber wings used to be specified for the Minor and certain larger vehicles, but they became more difficult to fit with the trend towards integral body construction with the wings (as part of larger pressings) on the larger as well as the smaller types. The G.P.O. therefore agreed to accept standard metal wings. There has been no evidence to show that this was a decision to regret. In preference to normal-control chassis, the Morris Commercial LD type has been adopted as the standard chassis for 240cu.-ft: postal vans and modified by the fitting of twin rear wheels for 360cu.-ft. postal vans also. The standard factory-built body of this model is satisfactory for the smaller load-carrier but is insufficiently high inside for use on the larger, and 360cu.-ft. bodies to G.P.O. specification are being built by contractors. The first 50 such bodies have just been completed by Longwell Green Coachworks, Ltd., who are employing reinforced plastics. The sides and rear doors and tailboard are colour impregnated, but the roof is translucent. Steel stiffeners are used where necessary. The G.P.O. have had satisfactory experience with plastics bodies, a number of Seddon 25 cwt. engineering vehicles obtained some years ago having been fitted with them.

The LD vehicle in both its forms is fitted with the B.M.C. 2.2-litre diesel engine. After a series of tests extending over several years, the G.P.O. decided to specify diesel engines for all new vehicles of I-ton capacity or more, or in other words those which Would have a petrol engine of about 2 litres or over.

One hundred vehicles of both types were involved in the tests, and vans were paired to carry out similar work. The eventual analysis, made in November, 1959, after two years of experiment, was that 240cu.-ft. vans with petrol engines had an average fuel cost per mile of 3.26d., compared with 2.02d. per mile for those with 2.2-litre oil engines. Vans of 360cu-ft. capacity with petrol engines averaged 4.63d. per mile, and those with 3.4 litre diesel engines 2.35d.

These savings meant that each 240cu.-ft. van, if converted to diesel, would be 29 cheaper to run in a year in which 11,500 miles (an average figure for vehicles of this type) were run. The comparable saving for a 360cu.-ft. van during a 13,900 mile year was reckoned at 101. The sums were then adjusted to take account of the training that drivers and mechanics would require to become familiar with diesel engines. A sum of 9s. 2d. per vehicle was deducted for driver instruction and 1 ls. for mechanics' tuition. To cover the cost of the installation of oil-fuel tanks where they would be needed at garages provided only with petrol storage, 5 16s. was subtracted. This reduced the savings on account of fuel costs by 8 16s. 2d. Furthermore the comparisons took account of higher depreciation and interest charges for oilers, and maintenance costs were also taken to be higher.

The latter was attributed to the fact that, allowing for the higher initial costs and higher maintenance charges during period of test, the test period was not long enough for the full life of the diesel engines to be run. It was acknowledged that diesel maintenance costs would probably be lower than petrol if this had not been the case, but it was considered prudent for the purposes of the analysis to err on the side of severity.

Even so, and in spite of the fact that, the case against diesels was deliberately weighted, the diesel gained the decision, and the conversion policy is now in progress. How long it will take for the petrol engine to be abandoned in the bigger vehicles is difficult to judge because of the impossibility of following a fixed vehicle-replacement programme. At the rate that money has been granted by the Treasury to the G.P.O. over the past few years, it would appear that Minor vans have to last for 10 years; 10cwt, types 12 years; 240cu.-ft. and 360cu.-ft. vans 14 years and the larger engineering vehicles about 20 years. The G.P.O. buy up to 5,000 vehicles a year.

Tests had also been made with a Perkins Four/99 engine in a JB van. Similarly there had been trials of a JB with a B.M.C. 948 c.c. "A" series petrol engine and modified rear axle. The Four-99 engine was also tested in a Hillman car.

Attention has been paid to lubricants in the constant endeavour to diminish expenses, but experiments with multigrade oils in petrol vehicles showed an insignificant saving in fuel consumption compared with the use of ordinary oil. The tests are continuing to determine whether engine life was enhanced by the more modern lubricants.

Until November, 1959, the G.P.O. had been using a straight mineral oil in petrol engines and a heavy-duty oil in diesel engines, but it was realized that the former was hardly up-to-date practice and that, with the forthcoming expansion in the use of diesel engines, it would be of great benefit to have a common engine lubricant for both types. In April this year oil to specification DEF.2101 B was adopted for all vehicles, both petrol and diesel. This is a heavy-duty oil of fairly low detergency which is used for most Government vehicles, and viscosity SAE 20 is specified by the Post Office.

Tecalemit automatic chassis lubrication equipment with nylon tubing has been experimentally fitted to about 200 x 240cu.-ft. and 360cu.-ft. forward-control vans. In the long distance fleets of the Supplies Department and the Engineering Department there are, approximately 400 big vehicles, and a number of these has been equipped with automatic chassis lubrication plant of the, heavier type. These two fleets are to be amalgamated.

The maintenance programme laid down for G.P.O. vehicles is at present in a state of transition both in respect of the intervals at which certain jobs are done and to whom they are entrusted. Negotiations with the trade unions concerned are involved before new policy in this respect can be fully implemented.

At present. engine oils are changed every 3,000 miles and filters of light vehicles at 6,000 miles and of heavier outfits at 10,000 miles. Greasing will be done on postal vehicles every fortnight and on engineering vehicles monthly. Another suggestion is for the docking of vehicles at 7,500 and 10,000 mile intervals according to type, for preventive maintenance inspections. Work done on any of these occasions would be to ensure trouble-free running until the next docking was due. In the case of postal vehicles this would be on the average every seven months and engineering vehicles every year.

It is considered preferable where practical and economic considerations allow, for drivers to be relieved of maintenance and servicing duties (other than replenishing petrol. engine oil, water and air) and for this work to be done by workshop staff. This practice is gradually being extended, and currently about 38 per cent. of all postal vehicles and 33 per cent. of engineering vehicles are wholly looked after by workshop staff. All vehicles, however, whether serviced by driving or workshop staff, are at present inspected by a mechanic at intervals

of between one and four weeks according to type and other factors, but under the new scheme all vehicles will be inspected monthly and postal vehicles will receive, in addition, an intermediate examination for "safety items," that is steering, brakes, tyres and lights.

In each of the nine regions into which the G.P.O. divide the country for their administrative purposes there is a motor transport officer who is responsible for the maintenence, overhaul and replacement of vehicles. Some have all the workshop facilities required, but there are in addition four big central repair depots at which vehicle rebuilding and repairs, component reconditioning and tyre retreading are carried out on an extensive scale. These are at Kidbrooke (S.E. London), Yeading (Hayes, Middx), Bamber Bridge (Preston) and Coseley (Wolverhampton).

Kidbrooke depot undertakes the complete overhaul of heavy vehicles, motorcycles and mechanical aids employed in the London and Home Counties regions, whilst Yeading depot is responsible for the light vehicles and special vehicles Used in these areas. Bamber Bridge undertakes part of the overhaul work emanating from the north-eastern and northwestern regions, and Coseley serves part of the Midlands.

Work entailing the reconditioning of components, including engines, may be received by a depot from distant regions which do not send their complete vehicles in for rebuilding.

The Yeading depot, which I visited, rebuilds some 150 vehicles a month as well as dealing with numbers of components. For example 50 x 6v. and 50 x 12v. batteries are rebuilt every week, and 350 tyres are recapped in the same period.

Work at the depot proceeds on the basis of" production " rather than "rebuilding," and the extensive shops are laid out along lines as they might be in a factory. Vehicles are collected by drivers, and before dismantling a note is made of any special fittings and tyre equipment. Bodies are then removed from the chassis, and it is to the body that the identity of a vehicle is attached throughout the reconditioning process. When this is completed, a van may have a different chassis, engine and other parts, but the body and the registration number are the same as at the start.

A detached body is steam cleaned before being taken into any one of a number of bays for repair. It is later prepared for painting, which is done when it is remounted on a rebuilt chassis. After rubbing down, filler and undercoat are applied, and the vehicle spends half-an-hour in a heated booth, of which there arc four. Green vans need only one topcoat because the covering power of green paint is superior to red. With a red van, the first coat after the undercoat is a 50-50 mixture of undercoat and topcoat, and this is followed by a full topcoat.

After the application of transfers, the van is varnished. then handles and other accessories are replaced, and the masking paste is wiped off. This is used in preference to masking with paper and tape. The topcoat used is a quick drying synthetic. There are two spray booths at the depot, one for green and the other for red vehicles.

A separate department is concerned with work in reinforced plastics. Certain body panels for older vehicles can no longer be obtained as spares from the manufacturers. What is more simple than to use one as a mould in which plastics components can be laid up?

It is true that there is a slight discrepancy in the-dimensions, but this is so small as to be negligible. As well as wings, complete van sides are being produced in this way. 'Battery boxes are also being made because of the plastics' resistance to attack by acid, and for motorcycle leg-guards a method has been evolved for the impregnation of lettering in the resin.

Glass-fibre Matting Another interesting procedure is the application of a thin layer of resin and glass-fibre mat to the floors of cabs, both inside and out, for protection against rust. This has proved extremely effective in preserving the metal, and the task is more straightforward than using a bituminous or rubber based preparation as is normally employed.

Reverting to the stage at which chassis separated from bodies are stripped, the various parts are kept together as systems, each set to follow a different course throughout the depot until they meet again on the assembly lines for the different models. For example, the electrical harness and accessories are put into a tray to be taken into the department where there is special -equipment for testing and reconditioning them. •

Costing at all stages in the depot is thorough, as the establishment's sole reason for existence is in being able to supply reconditioned vehicles and parts more cheaply than they could be bought from manufacturers. In certain instances, it is not possible to beat the manufacturers' prices and for this reason semaphore direction indicators are not among the many units rebuilt at Yeading. This is probably because the number received is too small for quantity-production, or quantity-reconditioning, methods to be applied. Nevertheless the difference in price is marginal, and I quote this example to underline the vigorous economy which is exercised.

Parts such as engines, gearboxes and axles are degreased and decarbonized before proceeding into the workshops. There are two Tricchlorethylene tanks and four in which Magnus caustic solution is used. Certain parts are blasted in a Spenstead machine with coconut shell, this being used in preference to sand which was found difficult to remove from such channels as oil galleries.

The machine shop is extremely well equipped, and in one section there are the facilities for the recovering of crankshafts by the process of metal spraying. The ends of axle shafts where the oil seals are fitted are also returned to standard size by the same process.

The various systems are put together again and tested, and are fed to the lines along which the vehicles are rebuilt. When the body is refitted and the vehicle is almost complete, it is lubricated before being taken into the paint shop and after painting there is a final test before the vans are sent out ready again for service.

There is a large joinery shop at Yeading, and a bodybuilding department where vehicles such as those for the long-distance fleets are constructed. A varied range of woodworking machines are used to produce parts for the reconditioning of vans and the construction of new bodies.

At Yeading, as at Coseley and 13araber Bridge, the G.P.O. have a tyre-recapping plant of Tyresoles manufacture operated by G.P.O. staff. The three depots retread tyres garnered from the whole country except Ulster and parts of south-west England and Scotland. These areas, and any tyres of odd size for which the G.P.O. do not themselves have suitable equipment, are dealt with on a contract basis.

The depots retread 41,000 tyres a year in 20 sizes. The average rejection rate of covers submitted is 35 per cent., although this can be 45 per cent. in certain areas where flints are liberally used for surface dressing.

Retread Life It has been shown by controlled tests that a retread will last for 70-80 per cent. of the mileage of the new tread, and it is reckoned that an original tyre can be retreaded twice. An analysis of 300 new tyres and 300 retreads used on the' Morris Z-type van, size 4.50-17, revealed an average tread life of 15,500 miles for new tyres and 11,500 for retreads. . An interesting comparison can be made between the 4.50-17 covers as fitted to the Z-type and the 5.00-14 tyres with which the Morris 4--ton van is equipped. It might be thought because of the latter vehicle's smaller tyre size and independent front suspension that tyre life would differ. Thirty 5.0044 tyres were checked, however, and the life of their original treads was found to average 15,100 miles, only fractionally less than that of the 4.50-17.

The 5.50-18 tyres on Morris Y-type vans average 18,500 miles for the new tread and 13,200 miles for the retread. Corresponding figures for the 32 x 6 equipment of 240-cu.-ft. vans are 23.400 and 20,000 miles respectively.


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