The wiper motor is a Lucas unit driving both wiper arms through a cable or link mechanism, with a self-parking function that returns the blades to their rest position at the base of the windscreen when switched off, and two speeds, a normal speed for steady rain and a fast speed for heavy downpours. Two distinct motor types were used across the production run and they are not interchangeable, the DR2A fitted to 3-synchro Roadsters from 1962 to 1967, and the 14W fitted to 4-synchro Roadsters and all GTs from 1968 onwards, which is the type also shared with the MGC. The 3-synchro GT originally used a 12W type which is now obsolete and for which most new parts are unavailable, though it can be replaced with the 14W using the correct gear, so any motor suspected of being the 12W type should be confirmed before parts are ordered.
Motor Service & Brushes
Reconditioned exchange units are available for both the DR2A and 14W types. The 14W is repairable, with brush kits available to restore a motor with worn brushes before condemning the unit, though the 14W has two variants of self-parking switch, a screw-fitting type and a clip-fitting type, and the correct brush kit depends on which is fitted, so this should be confirmed before ordering. The self-parking switch and motor seating pad are available as separate replacement parts, and mounting rubbers and retaining straps in standard or stainless steel are also available. Common faults include sluggish operation indicating worn brushes or a failing armature, intermittent stopping suggesting a faulty internal switch or corroded connections, and failure to park correctly caused by a worn or maladjusted park switch.
Before replacing the motor, the earth connection and wiper switch should be checked, as a poor earth is the most common and easily rectified cause of sluggish or non-functioning wipers.
Gears, Wheelboxes & Drive
The gear and link assembly controls wiper sweep angle and must match the application, as different sweep angles are specified for the Roadster and GT and fitting the wrong gear will result in inadequate screen coverage or the wipers overrunning the intended sweep area, with the stamping on the existing gear the most reliable identification guide. Wheelboxes are the pivot assemblies mounted in the scuttle panel through which the wiper spindles pass, and worn wheelbox bearings cause the wiper arms to wobble and eventually seize. Wheelboxes differ between Roadster and GT and are not interchangeable, and within the Roadster between 1962 and 1963 onwards. The drive rack or link mechanism connecting the motor to the wheelboxes should be checked for freedom of movement whenever the motor is removed, as a stiff or partially seized rack puts excessive load on the motor and causes the symptoms of sluggish operation often incorrectly blamed on the motor itself.
Bezel kits, seals, the drive rack casing, and the rack itself are all available individually or as complete assemblies.
Intermittent Wipers
An intermittent wiper kit with variable delay is available for both positive earth and negative earth cars, fitting within the existing wiper switch so the original dashboard appearance is completely unaffected.