Today I dismantled the front caliper to clean it out, check the seals, and make sure the piston was operating smoothly. There was no indication of trouble with the brakes beforehand, but since the brake hoses and brake fluid were so old, it is worth checking out before going for the first ride. Getting the piston out of the caliper was the most difficult part, but mostly because of my previous actions.
The service manual procedure for removing the piston is to use compressed air through the brake hose connection point after the caliper is removed from the motorcycle. I don’t have a very good air nozzle on the compressor and could not get the piston to budge with that method.
I later found on the GS Resources pages that removing the pads and using the brake fluid to push the piston out was an option, but a bit messier procedure. I had already bleed the brakes and removed everything from the motorcycle, so I created my own setup in the basement workshop to be able to utilize the hydraulic pressure to remove the piston.
Here is the front brake lever and master cylinder mounted on a pipe clamp with the front caliper attached with the rear brake hose.
I wasn’t worried about the brake caliper hanging from the brake hose because I will be installing new brake hoses later.
I used the brake fluid I had recently bleed out of the brake system rather than waste some new fluid, had to prime the master cylinder, and bleed the brake to get the piston to start moving out of the the caliper. If I had done this first on the bike, I would have just removed the brake pads and squeezed the brake lever until the piston came free.
Piston pushed out:
Once the piston was out, I removed the o-ring and dust deal and cleaned everything up. The seals and piston appear to be in good shape, but I will probably get a couple of new seals for $15 before rebuilding the caliper.
The brake pads also appear to have plenty of life left in them. The pads are EBC Organic Kevlar Model No. FA65, which must have been replaced fairly recently and are what I would have chosen if I was to replace the pads so I’ll also leave those in place for now.