I’m converting this RS model to a RT. The only difference in the brake system is the length of the hose from the front master cylinder to the front brake line splitter underneath the gas tank as the RT handlebars are wider so that hose is longer. The rear brake system is the same on both the RS and RT models
I previously rebuilt the two front and one rear calipers and rebuilt the rear master cylinder. The front master cylinder was so badly corroded that I replaced it along with the entire right handlebar perch. I also installed the three disk brake rotors on the newly powder coated wheels. You can read about how I did that work here.
- 34 BMW 1983 R100RS Disassemble, Inspect & Rebuild Brembo Brake Calipers
- 34 BMW 1983 R100RS Disassemble, Inspect & Rebuild Master Cylinders
- 34 BMW 1983 R100RS Remove, Refinish, Install Disk Brake Rotors
Here is the documentation of how I install the rear brake system and a short video summary of the procedure.
VIDEO: 1983 BMW R100RS/RT Install Rear Brake System
The master cylinder in on the right side while the rear brake caliper is on the left so there is a long steel brake line between the master cylinder and a bracket on the left, lower frame gusset where the flexible brake hose from the caliper attaches to the steel brake line. That’s a long run of brake line and I use my “Air Zapper” to help pull the air out of the line.
I finished up bleeding the rear brake system by pumping the rear brake pedal and opening and closing the caliper bleed valve to get the last bit of air out of the system. I now have a solid rear brake all set to stop.
So next up is installing the front brake system.