Transporters get ABS
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• Volkswagen's UK Transporter range is now available with a Bosch anti-locking braking system (ABS). The foursensor three-channel system, which has been offered on left-hand-drive versions since September, costs 11,127 retail ex-VAT.
ABS braking can be fitted to all the Transporter and Caravelle models, except the Syncro 4x4 derivatives — ABS-equipped Syncro models will be available by mid-1987.
VW's engineers have been working on anti-lock braking systems since 1971, first with Teldix, and latterly with Bosch. Extensive testing in North Sweden has resulted in the adoption of a Bosch system that leaves the standard braking system unchanged. The Transporter is the only one-tonne panel to be offered in the UK with full ABS.
The rear-engined layout of the Transporter means there is a greater share of the braking force on the rear wheels, and sensors have been fitted to all four wheels as a result.
Given the slip behaviour of both rear wheels, regulation of the ABS system is on a 'select-low' basis. This means the rear wheel with the lowest coefficient of friction determines the combined pressure for both rear wheels through the single channel modulation of the rear axle.
An anti-lock braking system for light commercial vehicles will be put into production next year by Automotive Products. The system, which is already fitted into a five-tonne test bed van, will be very competitive against other commercial vehicle braking mechanisms that can add up to £2,000 on the cost of a
vehicle, according to AR
The AP/Lockheed Antilok' system has no moving parts apart from the solenoids. It simply taps into the vehicle's existing hydraulic or air braking lines, although an auxiliary pump can be provided.
Electronic sensors on the front hubs and on the rear axle detect the vehicle's deceleration against a pre-determined value. When that value is reached, the system operates the modulating antilock servo, and cuts off the master cylinder from the brakes.
Designed originally for small front-wheel-drive cars, the three channel commercial vehicle anti-lock brakes have been adapted from the two channel system costing £150 that will be fitted to one of Europe's biggest selling passenger cars early next year.