Sunday, June 5, 2011

Part 12 - Front Brake

The motorcycle front brake is a DNA unit (DNA P/N M-BC-1002) that comes complete with 3/8-24 banjo bolt, 3/8 crush washers, mounting bracket, caliper, brake pads and 2 different length 3/8-16 mounting bolts. The only part not supplied is the banjo. A 90 degree banjo works well for this application.

Front brake components

The shorter mounting bolts are used to bolt the bracket to the matching mounting point on the front shock. For final installation, use blue locktite and the correct torque spec. Since this is mockup, I'm doing neither.

Mounting bracket installed
In order to center the caliper with respect to the motorcycle brake rotor, spacers are needed. In this case spacers needed to be around 0.070 inches. I used 3/8" steel washers I happened to have lying around. These are okay for mockup but will corrode in final application. Better to go with stainless steel or aluminum. The spacers fit between the caliper and the mounting bracket to center the caliper with respect to the rotor. Stainless steel spacers of varying thickness are available from many sources ( for example). You can stack them to achieve the required thickness.

Front caliper with spacers before installation

After the caliper is secured, the banjo and banjo bolt can be fastened in place. A crush washer is placed on either side of the banjo. Left finger tight for now. Final  torque is 30-35 ft/lbs. Once crush washers are crushed, they need to be replaced - do not re-use them.

Banjo and banjo bolt

Finally the brake line is attached to the banjo and fastened. The other end of the brake line is connected to the front brake reservoir on the hand controls.

Thats all for now. This post will be extended with final brake bleeding info. Before operating any motorcycle after working on the brakes, double check to make sure all hardware is torqued correctly and that there are no leaks. Any sponginess is evidence of air in the system and requires the brakes to be bled. Always test the brakes at slow speed before venturing into traffic. You need to make sure the brakes work properly before driving at street speeds. 

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