Advertisement
4.1.1. Place the turnplates centrally in front of each front wheel with the curve facing downwards. Drive the vehicle onto the turnplates
(fig.2). nEVEr attempt to carry out any wheel alignment without positioning the vehicle correctly on the turnplates.
4.1.2. turn the steering wheel to the straight-ahead position and lock it in position with the spring loaded steering wheel clamp positioned
between it and the driver's seat (fig.3).
4.1.3. Hang the alignment assemblies onto the top of the rear tyres and make adjustments, so that the horizontal bar is sitting at
approximately the centre of the wheel and touching the tyre at both ends. Ensure that the scale is at 90° to the wheel. check the spirit
level to ensure the correct position is achieved (fig.4).
4.1.4. Mount the laser measuring heads onto the front wheels with the toe scales to the front of the vehicle. the black locking hand screw on
the assembly allows the hanger to be shortened or lengthened to suit different wheel sizes. set the hand screw so that the hanger sits
on top of the tyre and the three 40mm locators touch the wheel rim. check the spirit level to ensure the bubble is centred (fig.5).
4.1.5. switch the switches on the laser measuring heads to position I, the laser can be observed hitting the rear scales (fig.6). check the
reading on each scale, add the readings together and divide by 2. for example: if the nearside scale reads 3 and the offside scale
reads 5, adding together and dividing by 2 equals 4, making each side in this example 4.
4.1.6. Adjust each track rod end to achieve this reading, when both rear scales are equal, the front wheels are aligned. Leave aligning
equipment in place for the next check.
fig.4
4.2.
FronT wheel Toe angle (TraCKing)
toe angle, also referred to as tracking, relates to the way in which the actual width of the wheel track varies between the front edges
when compared to the rear edges of an axle's wheels. (see fig.9 - in this case B is greater than A). As viewed from above, the front road
wheels, will either be pointing towards the centre line or away from it. If the wheels point away from the centre line, they are said to be
toed-out (also called negative toe); in specification books this will be represented by a number preceded by a minus sign. Wheels
pointing towards the centre line (as shown in the diagram), are toed-in (positive toe). Please note, in this simple front-only situation, the
steering wheel position is shown set at right angles to the centre line, and each front wheel equally set toed in to the centre line, with the
rear wheels parallel. toe angle is built into vehicle geometry to reduce the tyre wear to a minimum and to counteract any tension built in
by the other angles. Ideally once the vehicle is moving, the two wheels of a said axle should become perfectly straight (parallel) to each
other, In order to achieve this, when static the axle is set with a small amount of toe-in or toe-out. once the vehicle starts moving
forward, forces in the suspension and drive should pull the wheels almost parallel. However, most vehicles today will be set to have a
slight toe-in or toe-out, this is a result of vehicle designers compromising; for example, setting the wheels to toe-in provides better
straight-line stability whereas setting to toe-out offers a quicker steering response.
4.2.1. Each toe scale is made up of two colours, green for toe in and red for toe out. When the laser beam hits the toe scale (fig.7), if both
colours are the same then add the readings together, e.g: 2 green and 1 green means the axle is 3mm toe in: 2 red and 1 red means
3mm toe out. If the readings are different colours then subtract the lower figure from the higher figure, e.g. 2 green and 1 red means
the axle is 1mm toe in.
4.2.2. After calculating the above figure and obtaining your reading, refer to the vehicle manufacturer's settings to ascertain if adjustment is
necessary. If it is, adjust each track rod end by referring to the rear scale, making sure the rear scale readings remain equal at
all times. e.g. total toe on the toe scales is 1mm toe in and required total toe to be 3mm toe in. Adjust each track rod (fig.8), increasing
the rear scales from 4 to 4.5 or 5 on each side until arriving at the desired toe on the scale. If less toe is required on the axle, then
reduce the numbers on the rear scales.
4.2.3. If the vehicle has power steering, run the engine at this point. Lock up the track rod ends.
fig.1
fig.2
fig.5
Original Language Version
fig.3
fig.6
GA60
Issue: 1 - 23/02/10
Advertisement
