the rear since this eliminates the hand brake mechanism
and allows the use of the thicker front brake pads. Leave
the dust shields off.
Brake Master
Cylinders
The stock tandem dual master cylinder in the X1/9 is a
good unit, but there is no provision for adjusting balance
between the front and rear brakes. Also, the stockmaster
cylinder is located in a very inaccessible location which
complicates any maintenance on the master cylinder. It
is possible to use the stock master cylinder for racing if
you add a manually adjustable pressure limiting valve in
the line to the rear brakes. The valve used on the
128
sedans can be used for this function if you add a screw
adjusting feature to it. The preferred set-up for racing,
however, is to incorporate two master cylinders with an
Brake Master Cylinders
adjustable balance bar between them. Refer to the pic-
tures on this installation.
Use two
314
inch Girling master cylinders. Fabri-
cate the master cylinder mounting bracket and linkage
per Drawing
16.
The brake pedal has an existing hole, below the piv-
ot, which can be used for the new linkage to drive the
master cylinders. Cut a hole into the front trunk com-
partment to allow the brake pushrod to pass through.
Assemble the
mastcr cylinder bracket, rocker arm and
pushrod, and locate the assembly on the rear wall of the
front trunk as shown in the pictures. Weld the bracket to
the car.
After painting the installed master cylinder mounting
bracket, the cylinders and linkage can be assembled. Set
up the brake balance so the rocker arm pivot is slightly
closer to the front master cylinder for initial testing. Ad-
just this balance as required to obtain optimum front to
rear brake balance under racing conditions. PBS Kit
Number
12
covers the dual master cylinder parts.
Steering
Shaft
Location and Brake Master Cylinder Push Rod
ROLL CAGE
All SCCA production race cars built in 1979 andlater are
required to have a complete roll cage as defined in the
current SCCA
G.C.R. Since it is required, it is desirable
to integrate the cage carefully into the basic car structure
to enhance the stiffness of the chassis as well as to pro-
tect the driver. In addition, the cage should be designed
in such a way as to minimize its aerodynamic drag. The
roll cage described in subsequent paragraphs complies
with SCCA safety criteria and the above objectives as
well as being integrated into the basic styling of the X1/9.
Fabricate the main hoop and the front hoop from
1-112 inch O.D., .I20 inch wall, mild steel tubing per
Drawings
17
and
18.
The bottom ends of the two hoops
Front Camber Plate Installation and Brake Master
Cylinder Installation
will need to be trimmed to fit the installation.
Fabricate four base mounting pads from angle iron
or by bending steel plate and weld them onto the outer
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