FRAGMENTS ON FORGOTTEN MAKES No. 13: THE BROCKLEBANK SIX
AMONG the numerous makes of cars which existed in the earlier days of motoring, and which are now threatened with extinction, is the Brocklebank. About 150 of these interesting 14.9-h.p., six cylinder cars were built and sold between 1926 and 1929, in which year lack of sales aggravated by the industrial depression closed down the Birmingham works.
The outward appearance of the cars was governed by the type of body chosen by the purchaser, and no less than eight different models were listed at the 1929 Motor Show, ranging from the 4,5 seater Open Tourins. Car (£405) to the Gordon England Aluminium Panelled Saloon de Luxe (375). But in every case the coachwork followed strictly conventional, rather perpendicular lines dictated by the tall blunt radiator, and the chief interest of the cars lay in the standard chassis, which sold complete with wings, running boards, luggage carrier, lamps and instruments for £295.
At this moderate price Major John Brocklebank, who was both designer and builder of the car, sought to provide u degree of reliability, flexibility and convenience unknown in England in those times. He admired the smoothness and power of the six-cylinder American ears of the period, two of which—a Flint and a Cleveland— he personally owned. The Brocklebank, therefore, although it weighed only about 17 cwt. complete, was endowed with a sixcylinder engine, and can claim to be the forerunner of the “light sixes” which Lord Austin and others later successfully produced in great numbers.
The engine was notable for its massive S26 Alloy Steel crankshaft, which had 2-in. diameter journals and crankpins and was said to be interchangeable with the then current Chrysler six-cylinder crankshaft—a virtue which can only have been of use on the retest occasions! It turned in a crankcase east in one with the cylinder block, the base being closed with an aluminium sump. Bore and stroke were 63.5 x 108 mm., which gave a total capacity of 2,051-c.c. Pistons were of aluminium, and the valves overhead operated by means of a chain driven camshaft, pushrods and rockers.
The two-pressure lubrication system was advanced for its date, A gear type pump forced the oil at about 25 lb. sq. in. pressure to the main bearings and crankpins, then after passing through a relief valve at a considerably lower pressure, on to the timing gear and the rocker shaft, the rockers themselves being internally drilled to admit oil to the push rod cups. A peculiarity of the engine was the method of driving the magneto. This ran in tandem with the six-volt dynamo and the two were joined together by a short, universally-jointed shaft. The necessity for this resulted from the magneto being firmly bolted to the crankcase, while the dynamo worked as the tensioner on the camshaft chain and for this reason required soine lateral adjustment. An Autovac fed the single Stromberg 0.1.11 carburetter and the vertical pipe, which led up from this into the inlet manifold, incorporated an ingenious heating jacket, which allowed a controllable amount of heat from the adjacent exhaust to warm the ingoing mixture. The small amount of exhaust gas so used was then taken to sump level by a straight pipe and there released. Engine cooling was conventionally arranged with the aid of a belt-driven water pump and fan, and the system had the ample capacity of four gallons.
The transmission was conventional, except that the gearbox contained only three forward speeds and reverse, a matter which was commented sadly upon by The Times Motoring Correspondent on December 14th, 1926, after he had tested the car. This writer praised the lightness of the steering and found the suspension—by 1-elliptic springs all round—” distinctly efficient” if a shade over flexible. No shock absorbers were fitted, Isut Gabriel snubbers, as found on early Morris cars, were used to subdue excessive spring movements.
Perhaps the most up-to-date feature of the whole car was the internally expanding four-wheel hydraulic braking system by Lockheed. Unfortunately the records of this company do not go back to the 1920’s but the Brocklebank was, without doubt, one of the first English cars to have an hydraulic system. The brakes were unusual, at least on the earlier (1926-28) models, in having three shoes in each drum. This arrangement was known in America until as late as 1932, but it is rare to find it combined with an hydraulic system. In the case of the Brocklebank, each drum had one leading and two trailing shoes, and it is likely that the difficulty of adjusting all three shoes to work properly led to the adoption of two-shoe brakes on the Mark H chassis, which was introduced in 1928. The hydraulic system was fed by a small reservoir from which it was normally sealed off. When pedal travel increased, a plunger in the reservoir could be unscrewed from its seating and used to pump fluid into the lines. The hand brake worked on the transmission, a band. lined with friction material contracting round the drum-shaped housing of the front universal joint of the open propeller shaft. These brakes were generous for the weight of the car and they worked well. However, the car did not in other ways encourage fast driving. The engine, in spite of its robust design, did not respond quickly to the throttle—perhaps because the heavy crankshaft combined with the flywheel to increase inertia, and flexible though the engine certainly was, it allowed by all accounts a top speed of only about 60 m.p.h.
From the point of view of maintenance the Brocklebank must have been one of the most convenient cars ever made. The design of all parts needing periodic adjustment or attention was carefully planned with this in mind. For example, the sump could be drained by turning a handle near the top of the crankcase; valve adjustment was a matter of taking up or loosening hardened set screws on top of the rockers otherwise held by locking nuts t he instrument board, by releasing two wing nuts, could be tilted outwards, exposing the instruments and wiring. Wear in the clutch and steering box could be simply taken up, and there were many other practical features, even including the now fashionable central positioning of the petrol filler so that it could be reached from either side of the car.
But circumstances were against car manufacturers in 1929, and for all its merits the Brocklebank did not sell. Major Brocklebank was so much absorbed by the design and development of the car that the important work of promoting sales was perhaps neglected, although a demonstration saloon was arrestingly painted in two halves so that it appeared blue on one side and brown on the other. This arrangement caused trouble with the police in Berkshire where the car was kept, but, as they were not able to pin down the offence exactly, the matter in the end was overlooked !
It is doubtful if anyone who bought a Brocklebank when new still possesses it, but present owners almost certainly do exist. One car was heard of in Cheltenham since the war and news of another came front Australia. A one-time owner described his car as the early equivalent of a post-war Humber—comfortable, untiring to drive. but in its handling qualities not encouraging a great deal of dash. If this is so, and most of the advice given in the detailed Instruction Book (67 pages, 5s.) has been heeded, then there seems a good chance that some examples of this rare make will be found.—CharleS Brocklebank.