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techtalk:ih:wheels02 [2020/05/27 19:45]
hippysmack [Caliper ID and Applications]
techtalk:ih:wheels02 [2020/05/29 03:55]
hippysmack [Brake Disc and Pads]
Line 94: Line 94:
  
 ====== Brake Disc and Pads ====== ====== Brake Disc and Pads ======
 +From HD Teschnical Service Bulletin M-712 dated June 16, 1977: \\
  
-Disc and pad sets+//Disc brake friction material can be classified as organic, semi-metallic,​ or metallic. \\ 
 +Organic material will outwear an equal section of metallic material under normal operating conditions. \\  
 + 
 +An organic pad will also reduce heat transfer between the brake disc and brake fluid in the caliper. \\ 
 +It is also less harsh on the disc and usually leaves the disc with a polished look. \\ 
 +This material has two disadvantages:​ // 
 + 
 +  - //The organic material will fade when high pad temperatures are developed.//​ 
 +  - //Wet stopping power is very poor when the material is thoroughly wet. // 
 + 
 +//Metallic friction material increases it's efficiency as temperatures increase, and water has little effect on stopping performance. \\ 
 +Metallic linings, in normal service, have a shorter wear life than organic. \\ 
 +Semi-metallic have characteristics in between the organic and metallic. \\ // 
 + 
 +//Replace pads when the thickness of the friction material has worn down to 1/16" or less on all models except those specified in the paragraph below. \\ // 
 + 
 +//We suggest that you use only the recommended Harley-Davidson pads. \\ 
 +1974 thru 1977 XL, XLCH, XLT, FX, FXE, FXS models have a wear indicator slot in the front brake pad friction material. \\ 
 +Replace pads when the friction material has worn down to 3/32" thickness as shown in the illustration. ​ \\ // 
 + 
 +{{:​techtalk:​ih:​wheels:​1974-1977_brake_pads_drawing_by_hippysmack.png?​direct&​300|}} ((drawing by Hippysmack)) \\ 
 + 
 +Motorcycle brakes operate under high temperatures and can absorb far more horsepower than the engine produces. ((HD Teschnical Service Bulletin M-712 dated June 16, 1977)) \\ 
 +The discs do not need a polished appearance to maintain efficiency. \\ 
 +A disc with a slight amount of grooving similar to a phonograph record is normal with metallic brake pads and is acceptable if the surface is smooth. \\ 
 +The newer stainless brake discs may appear grooved, but if you run your fingernail over the surface you find there are no grooves. \\ 
 +Disc runout, on the motorcycle, should not exceed .015". If the disc becomes warped or dished beyond this specification it should be replaced. \\ 
 +Brake pedal travel is increased with the wave washer type of piston retraction. Caution must be used when adjusting brake pedal travel. \\ 
 +If the required freeplay in the plunger is adjusted away, the expanding brake fluid cannot return to the reservoir and gradual energization of the brake may occur. \\ 
 +If there is any doubt concerning this freeplay or other proper operation of the master cylinder; \\ 
 +The master cylinder cap should be removed and the pedal depressed several times. A squirt of fluid each time will verify proper operation. \\ 
 + 
 + 
 +**Disc and pad sets**:
 |Disc, Material|Pad| |Disc, Material|Pad|
 |-73, mild steel|organic| |-73, mild steel|organic|