This past weekend I finally finished my project to redo the front brakes on my '87 K75S. I took my time doing it. The advice from the forum was super helpful. A few items:
1) Loosening all the bolts, including the bolts that hold the caliper together while the caliper is mounted was key.
2) I installed new EBC rotors along with EBC HH sintered pads. Went together just fine.
3) The seal kit and slider pin kit worked quite well. I'd never rebuilt calipers before and by being careful and taking time, all went well.
4) Cleaned first with brake fluid then finished with brake cleaner. Let it all dry. Lubed the seal with brake fluid.
5) Put the caliper halves together and torqued to the suggested 50 NM in the instructions with the rebuild kit. Had to finished the torque with the calipers back on the bike. One rubber o-ring per caliper on my bike (each kit had two o-rings).
6) Took a long time bleeding with a vacuum bleeder plus some careful squeeze/turn/close/release bleeding to finish it. The vacuum bleeder did OK up but it didn't really do it without the traditional slow bleeding method. I'll be dealing with the master cylinder and brake lines in the future - I wanted to isolate on variables in case I ran into issues.
When I opened the caliper halves I found some remaining watery brown fluid. Glad I did this rebuild. Cleaned up fine but I suspect they'd not been rebuilt before (~30k on the odo) and who knows about the bleeding history. What triggered my rebuild was rapid brake pulsing. Rather than fight to solve it with 32 year old stock parts, I just replaced the pads and rotors. It stops so much better and smoother than before.
While getting parts and taking my time, I also redid the mounting bits for the instrument cluster and took a few trips to the hardware store to sort out fairing mounting hardware. I also replaced what I think was an Aeroflow windscreen with a stock screen. That is also a big improvement for me. Nice smooth airflow on the helmet. The Aeroflow seemed to create more buffeting for me, anyway.
I'm going to ride it a bit for a while. Maybe take up the brake lines and master cylinder later in the fall. She's feeling pretty good with new tires this spring, new rear Progressive shock, and new fork oil. Plenty else to sort through to keep me occupied.
I appreciate the help on the board. Hopefully I can share some useful things going forward.
Eville Rich
