David Brown’s 990 Implematic tractor was introduced in the early 1960s and was a popular choice for farmers, to the extent it became a serious competitor for the likes of Ford and Massey Ferguson.
Powered by a cross-flow, four-cylinder engine equipped with a CAV rotary injection pump, the 990 was rated at 52hp which, for the day, was considered a powerful tractor and meant, more often than not, that a three-furrow plough could be pulled.
In the transmission department, a two-range, three-speed box provided operators with a choice of six forward speeds and two reverse. Top speed was a heady 14mph (22kph).
For pto work, a two-speed drive system provided both 540 and 1000rpm although, for greater fuel economy, many chose to operate the 1000rpm at 540rpm at a lower engine speed.
The system also had “live drive” which meant declutching did not stop pto drive – the pedal needed to be pressed further down to clear the pto clutch.
Purchasers of David Brown 990 Implematic tractors, which were built at Meltham, south of Huddersfield, were asked to shell out a list price of 649-17s-6d (649.875p).
By the 1960s hydraulic linkage was a must-have feature and was fitted as standard to the vast majority of tractors.
David Brown, like several other manufacturers, had struggled to compete with the edge Ferguson tractors had gained with their patented Ferguson draft control system.
When the patent expired however, David Brown, with its 990, fitted a rudimentary draft-sensing system which used a Bowden cable to detect the lengthening or shortening of the top link – the theory being that the spring-dampened top link shortened slightly when excessive load is put on, say, by a plough.
When this happens the cable also shortens, activating the hydraulics to lift the plough slightly to reduce the draft load and lengthen the top link.
Before this system the company had fitted what it called TCU – Traction Control Unit – which put a set lift pressure on to a linkage mounted implement so that weight was transferred to the rear wheels.
DB990 tractors at this time were fitted with both draft and TCU systems.
Calling on the services of Leeds-based Jim Kierans and David Croft, both of who are owners of fine examples of David Brown 990 Implematic tractors, I was privileged to savour once again the delights of driving such a noble machine – after a gap of some 40 years.
And, having pressed the start button and heard that familiar sharp, almost staccato pulse of the DB engine, memories flooded back: Ploughing in sub-zero temperatures with only a cold bottle of tea and a ham sandwich for lunch, damp sacks spread across the knees, warming frozen hands on inlet manifolds, mowing in blistering sunshine, hauling a trailer loaded with grain filled sacks out of the harvest field…
Depressing the clutch pedal – a good beefy pedal from which a muddy boot could not slip off – the range selector lever is moved into high and the gear lever into second, always a good gear to start off in, I recall.
It was only on occasions ratios in the low box were used – high-first was usually about right for ploughing with low-third rarely required.
A short pull on the steering column throttle lever and, with the clutch engaged, we are moving.
There is that familiar gearbox whine as I open the throttle further and wonder about selecting top gear.
A few bone jarring bumps and I decide against it – David Brown 990 tractors had no suspension whatsoever, if one ignored the 2in thick seat cushion.
Indeed, in early 990 versions, you sat between two six-volt batteries which, if the seat mounting collapsed, caused some alarming shorting of electrics.
Luxuries such as power assisted steering, powershift or shuttle control had yet to appear but, none-the-less, the David Brown 990 was a well engineered and respected tractor which served its masters well.
David Brown, having been purchased by International Harvester which, in turn, became part of the Case empire, closed its Meltham works in the mid-1980s.