After covering high mileage many Morgan cars develop front wheel vibration(shimmy). If the wheels have been balanced properly and are free from distortion, the problem will most probably be caused by a need to adjust the steering dampers (see Figure 1). When the vehicle rides over bumps and the mainspring (1) is compressed' it tends to exert a rotary force on the hub carrier (2). At certain speeds this can lead to harmonic motions in the steering causing severe front wheel wobble (also known as 'shimmy' and often referred to as 'Malvern dance' in the Morgan world). In the early 1950's, to alleviate this problem, Morgan fitted a bronze thrust plate (3) between the hub carrier (2) and the mainspring. This was bolted via an aluminium spacer (4) to a spring steel damper blade (5) which was secured at the other end by a clamp bolted to the chassis. The bronze thrust plate isolates the rotational torque exerted by the mainspring to the hub carrier.
Damper adjustment
Figure 2
Closer examination of the damper blade clamp (see Figure 2 A)reveals it to consist of two metal plates (12) seperated by a couple of shims (9) and secured by two bolts (8) to the chassis. Adjustment requires loosening the bolts and butting the shims against the damper blade (10). Having re-tightened the bolts, make sure there is no radial movement(see Fig 2 B), but the blade is free to move in and out (see Fig 2 C) of the retaining clamp (12) as the hub carrier (2) moves up and down the king pin.
