Installation of this kit results in an interference fit between the MGB caliper and both the Spitfire rotor and the existing steering arm. Refer to figure 1 for proper installation.

Figure 1 shows the general arrangement of the installation and details the slight interference between the rotor and caliper which must be relieved by skimming the adapter face of the rotor, relieving the caliper locally, or both (see Interference Relief detail). Whichever method is used, remove only the minimum necessary from either part. Use caution in relieving the caliper to avoid damaging the piston seal.

Additionally, make sure that the chamfer on the bore of the adapter does not foul the hub, preventing proper seating of the adapter (see Corner Clearance detail). Relieve the adapter if necessary. SAE grade 8 bolts are supplied with the kit to attach the rotor and hub. However, since the adapter is aluminum, torque these fasteners to only 250 inch-pounds. Thread-locking compound is recommended.

To relieve the interference between the steering arm and the MGB caliper, refer to Figures 2 and 3. You have two choices:

1) Determine the correction necessary, and bend the steering arm enough to both clear the caliper and maintain the bump-steer geometry of the steering arm. Make the bend of equal arc on both sides.
2) Using the drawings provided, refer to figure 2. Install a spacer between the steering arm and the stub axle to relocate the track rod end which otherwise fouls the oversized Spitfire rotor. We have provided a drawing for reference purposes: 8S009revA. Additional modifications may be required to achieve the required bump-steer characteristics. The attaching bolts should be SAE grade 5 or better and have a grip range long enough to engage at least 1/8 of the unthreaded portion of the mating holes in the stub axle. Aircraft bolts AN6-22A and AN6-23A are recommended. Torque these to 300 inch-pounds.

Figure 3 shows where and how much the end of the shock
arm is relieved to eliminate contact with the rotor at full lock. Additional clearance can be obtained by using spacer washers between the thrust washer and the upper trunnion. Do not use more than 1/8 of spacer.
See HUF150 for the complete conversion kit including Calipers