GTM Libra - Main build manual

With the car level and in its final position recheck the ride heights to 5 ½ ″
taking into account any packing materials you may have used on the wheels.
The Steering Rack
Start at the front of the car. Before any adjustment can be made to the tow-in
at the front of the car it is necessary to determine the central position in the
steering rack. Moving the steering wheel to one extreme, measure the
amount of turn to the other extreme, halving the movement and determining
the central position can do this. Once these central positions have been
determined mark the top of the steering wheel with some masking tape and
check that the movement left and right is the same. Once you are sure you
have the central position it is a good idea to put the steering wheel itself with
its spokes in the central position so that when you drive the car it can be
clearly seen whether it is steering correctly.
Using a straight bar that will run from the front of the front wheel to the back of
the rear wheel, hold the bar halfway up the wheels and adjust the tow-in on
the wheel to give approximately a tow-in on either side of 2mm. On certain
Metro steering racks you may find it necessary to remove a small proportion
of the threaded end of the steering link to enable the correct adjustment to be
obtained. This can be done using a suitable hacksaw and file. Repeat for the
other side of the car.
The adjustment of the camber angles for the front wheels is both covered as it
has been found that this angle is pretty near correct straight from the factory.
The wheels at the front should be vertical and as long as your car does not
deviate from this measurement unduly our suggestions that you leave it at
present and tackle any changes at a later date. Methods of making
adjustment to the camber angle at the front are detailed at the end of this
manual.
Moving to the back of the car the set up is more complex. Camber angle and
tow in are both adjustable as well as the track that the car runs at.
The car runs with a rear camber angle of minus 1 ½ -2 degrees. This means
that the top of the tyre leans in towards the car by 1 ½ - 2 degrees. Set the
camber angles to be around this figure by adjusting the top wishbone
adjusting nuts on the outside face of the wishbone. Set the tow in to be
square with the front wheels i.e. neither towed in nor towed out.
Referring to the diagram and looking from the back of the car set the
dimension five 550mm on the driver's side of the car from the face of the
casting where the drive shaft protrudes to the centre nearest bolt on the
bottom wishbone. To obtain this adjustment it is necessary to adjust only the
bottom wishbone with the two locking nuts on the outside ball joint and then
re-adjust the top wishbone to obtain the correct camber angle. Working
similarly on the passenger side adjust the distance from the face of the
casting where the passenger side drive shaft protrudes to the centre of the
first bolt on the bottom wishbone to 365mm. Now re-adjust the top passenger
side wishbone to obtain the correct camber angle.
It is difficult to measure exactly these two dimensions but try to get them as
close as you can. An accuracy of plus or minus 2mm will be satisfactory, as
any slight error in the track will not in any way adversely affect the handling of
© GTM CARS LTD. 12.3