Pressure Differential Valve: Reassembly
Replace seals and copper washers with new ones provided in service repair kit. Lubricate parts with clean brake fluid during assembly. Install new seals on pistons with lips facing outwards. Insert long piston into bore (slotted end out) until radiused groove is opposite switch plunger hole. Insert ball (if equipped) and screw in switch assembly and torque to specification.
CAUTION:
Ensure that piston seals are never pushed across central hole in valve body as this will damage seals.
Insert short piston into bore with slotted end out. Install plugs with new copper washers and torque to specification.
BRAKE SPECIFICATIONS
| Application | Specification | ||||
|---|---|---|---|---|---|
| Rotor | |||||
| Diameter | |||||
| TR-4 & TR-4A | 11" (279 mm) | ||||
| Spitfire Series | 9" (229 mm) | ||||
| GT Series | 9.7" (246 mm) | ||||
| Max. Permissible Runout | |||||
| Installed | .006" (.152 mm) | ||||
| Removed | .002" (.0508 mm) | ||||
| Min. Thickness | |||||
| TR-4 & TR-4A | .440" (11.18 mm) | ||||
| GT Series | .460" (11.68 mm) | ||||
| Hub End Play | |||||
| Disc Brake Models | .003-.005" (.076-.127 mm) | ||||
| Drum Size | |||||
| 1200 (Front) | 8 x 1 1/4" | ||||
| TR-4 & TR-4A (Rear) | 9 x 1 3/4" | ||||
| Spitfire Models (Rear) | 7 x 1 1/4" | ||||
| Master Cylinder (Non-Tandem Unit) | |||||
| Bore Diameter(1) | |||||
| Single Ring | .75" (19.05 mm) | ||||
| Double Ring | .7" (.7-.78 mm) | ||||
| Piston Stroke | |||||
| Max. Available | 1.38" (35.05 mm) | ||||
| Stroke At Cut-Off | .099" (2.5 mm) | ||||
|
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TIGHTENING SPECIFICATIONS
| Application | Ft. Lbs. (mkg) | ||
|---|---|---|---|
| Disc Brake | |||
| Rotor-to-Hub | |||
| Spitfire IV | 30 (4.1) | ||
| All Other Models | 33 (4.5) | ||
| Caliper-to-Mounting Plate | |||
| Spitfire IV | 58 (8.0) | ||
| All Other Models | 52 (7.1) | ||
| Pressure Differential Valve | |||
| Plunger Switch | 2.5 (.3) | ||
| End Plugs | 18 (2.4) | ||
| Wheel Nuts | |||
| TR-4 | 50 (6.9) | ||
| All Others | 40 (5.5) | ||
DISC BRAKE ROTOR SPECIFICATIONS
| Application | Disc Diameter In. (mm) | Lateral Runout In. (mm) | Parallelism In. (mm) | Original Thickness In. (mm) | Minimum Refinish Thickness In. (mm) | Discard Thickness In. (mm) |
|---|---|---|---|---|---|---|
| TR-4 & TR-4A | 11.0 | .006 | .... | .... | .440 | (1) |
| (279.0) | (.15) | .... | .... | (11.17) | .... | |
| Spitfire | 9.0 | .006 | .... | .... | .... | .... |
| (229.0) | (.15) | .... | .... | .... | .... | |
| GT6 | 9.7 | .006 | .... | .... | .460 | (1) |
| (246.0) | (.15) | .... | .... | (11.68) | .... | |
| TR6 | 10.85 | .006 | .... | .... | .... | .... |
| (276.0) | (.15) | .... | .... | .... |