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The 'CI and :4' Bureau is a CM service. its
Page 96
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expert staff will gladly answer your ueries Lett ers Q. Q.
should be addressed to: "0' and A' Bureau Commercial Motor 40 Bowling Green Lane 40 Bowling Green Lane Commercial Motor
London, ECI and
Q.
should be addressed to: "0' and A' Bureau
QWe operate a tipping lorry on farm work and understand that if the vehicle is restricted to a five-mile radius of base it does not require plating.
Could you let us have an answer to this question as we can get no direct answer from any other source ?
AThe only exemptions from plating which
might apply to your vehicle are to be found in "The Goods Vehicles (Plating and Testing) Regulations 1968 Schedule 2 (17)". This gives exemption to "vehicles exempted from duty under the 1962 Act (The Vehicles (Excise) Act 1962). by virtue of section 6 (6) of that Act and any trailer drawn by such a vehicle".
The section 6 (6) referred to states: "If an applicant for a licence under this Act for any mechanically propelled vehicle satisfied the county council that the vehicle is intended to be used on public roads—
(a) only in passing from land in his occupation to other land in his occupation, and (b) for distances not exceeding in the aggregate six miles in any calendar week. then, if authorized so to do by the Minister with the consent of the Treasury, the council may exempt the vehicle from the duty chargeable under this Act in respect of the use of the vehicle on roads."
aCould you advise me what brake effi
ciencies are required for a three-axled articulated vehicle which carries a manufacturer's plate giving the axle weights, and a gvw of 18 tons? The vehicle is of pre-1968 manufacture.
I am told that the brake efficiency must be 50 per cent for the service brake and 25 per cent for the secondary brake, but if I remove the manufacturer's plate then the efficiencies which apply will be 40 per cent and 15 per cent respectively.
Also, am I correct in thinking that a tandem-axied semi-trailer plated at 24 tons by the MoT cannot run at this weight unless it is also fitted with a manufacturer's plate, even though it is hauled by a plated tractive unit?
AThe answer to your first query is that your
three-axled artic plated Ion the tractive unit) for 18 tons will need to have braking efficiencies of 40 per cent service and 15 per cent secondary. The situation is not affected by the fact that it carries a manufacturer's plate even though it is likely that the vehicle will have been designed to give the higher figures of 50 per cent and 25 per cent respectively.
It seems clear from the regulations that the manufacturer's plate has significance only in allowing the higher weights allowed since 1964 (over 20 tons for a three-axle artic) and as your outfit is below this figure, 40 per cent and 15 per cent are satisfactory even though it carries a plate.
To answer your second question, we pre
sume that the 24 tons refers to the gross trailer weight of the semi-trailer—if used in an outfit grossing more than 24 tons it needs a manufacturer's plate. To operate at the post1964 gross combination weights (over 24 tons and up to 32 tons) both parts of an articulated outfit have to be plated by the manufacturer.
It is worth pointing out in this case that the MoT plate will have been issued on the basis that the semi trailer, not having a manufacturer's plate, would be used in an outfit requiring the reduced brake efficiencies of 40 per cent and 15 per cent.
QIs an hgv driver's licence required to
enable a psv to be driven even when it is not used for carrying passengers—for example, if it is being taken to a workshop for repair or painting? Also, does a person being trained to drive this type of vehicle need an ordinary provisional driving licence and a provisional figy driver's licence?
I have been told that the holder of a psv driving licence will need an hgv driver's licence when his ordinary driving licence expires and that a medical examination is required to obtain a provisional hgv driver's licence. Are these facts correct?
AA driver of a psv does not require an hgv driver's licence whether the vehicle is carrying passengers or is empty and is being taken for repairs or painting.
In the case of trainee drivers, they would need only ordinary provisional licences.
A medical test is required to obtain a provisional hgv driver's licence.
QI have had 12 years' experience on heavy goods vehicles, including artics, and have a current psv licence.
Could you give me some details regarding training schools, including costs etc. for would-be hgv driving instructors.
AThe British School of Motoring offers a
course for experienced hgv drivers who wish to become instructors. It is of a week's duration and costs [112 10s Od plus accommodation. It is based on the use of articulated vehicles and has the sole aim of teaching how to teach, although it can conclude with the hgv driving test if required. For more details we suggest you contact Mr King of the BSM Commercial Division. telephone 01-352 1014.
There is also a demand for good hgv men among haulage operators, and firms covered by the RTITB can nominate employees for the (free) hgv instructors' course at Motec 1, High Ercall, Shropshire.
CI We run a fleet of five SB1 and SB5 Bedford-Duple Coaches, all 41-seaters, but we are now after a Bedford VAL or Thames 52-seater. Regarding the Bedford VAL, I gather they are always having to have brake adjustments. Could you tell me what the price of fitting an exhaust brake would be and has this any detrimental effects on the engine?
I gather a Telma retarder works out at £350 and thought an exhaust brake might be a lot less than this, but is it so efficient? Regarding the Ford 1964 Thames 52-seater, do you think the 330 engine is powerful enough as it was not until 1966 that the 360 diesel engine was brought out?
AThere do seem to have been many com
plaints about VAL brakes, though why this should be so extensive is hard to understand. It is obvious that a vehicle having smalldiameter tyres and wheels cannot have largediameter brake drums and one would immediately assume that this would necessitate more frequent brake adjustment; this has never become apparent on any of the road tests carried out by the staff of this (ournal, and VAL brakes have not been shown to be in the least suspect. During recent conversations with Bedford engineering staff, a point was raised regarding the large incidence of incorrect adjustment which was being discovered on VALs by the Vauxhall service dept. It is wellknown that correct centralizing of brake shoes is essential if adequate life between adjustments is to be achieved. This may be part of the answer.
You are correct in assuming that the Telma costs about E350 but this item is not approved by Vauxhall: the reason given is that it can tend to overload the thrust bearings in the differential. It is, nevertheless, widely used and is extremely efficient. It makes immense savings in the wear and tear of brake liners, We have ascertained that there is an exhaust brake kit for the VAL when this is fitted with the Leyland 0.400 engine. The Bedford part number for the kit is 7161346.
You may Or may not be aware of the limitations of exhaust brakes. This device is a shutter valve which closes off the exhaust gas flow and therefore has a retarding effect on the engine by producing back pressure against the piston crowns. The unit is effective only when the engine is turning at relatively high speeds and will not produce sufficient retardation if the vehicle is travelling slowly in a high gear.
The correct method of use on occasions for which the exhaust brake is primarily intended (descending hills) is that the transmission should be in the same gear that would be needed to climb the gradient the vehicle is descending. The degree of retardation obtained in these conditions is adequate to dispense completely with the need to use the service braking system.
Regarding your comments about the Thames, this was not made after 1965; the Ford passenger chassis after that date for 52-seater bodywork was. and still is, the Ford R226. You are, in our opinion, correct in assuming that the 330 cu.in. engine was low on power for this application.