Master Cylinder Maintenance Schedule

[cowboyup3371]

In late 2011 or early 2012, I installed the Kawasaki Ninja twinpot calipers from a 1989 650 and a 2008 Kawasaki Ninja Front Master Cylinder. At the time, I replaced the seals for the calipers but not the pistons. I also did not rebuild the master cylinder since I figured it was still new enough that I wouldn't need to. Furthermore, although the lever pull wasn't "lock up the front wheel" tight, it stopped me well enough. Unfortunately, I developed a leak from the calipers at the end of 2012 which is what helped start my bike rebuild sooner than I originally anticipated.

When I started the bike rebuild, I decided to replace everything in the calipers this time so new pistons and seals are in place. Although I successfully bled the rear brake this week without assistance, I had to ask Steve for help on my fronts because I didn't feel like I did it correctly. After he spent time ensuring we didn't have any air coming from the lines, I still didn't have good strong pressure at the lever with both calipers attached. Yet, having only one brake caliper attached seemed to be okay. After reading up on some information in a couple of Kawasaki forums and the parts fiche, I know both bikes were designed for dual calipers. I also read that many folks say my problem would be corrected by rebuilding the master cylinder. Consequently, I ordered a new master cylinder piston cup set from a local dealer today and should have it in by mid-weekray:

However, the fact I am facing this now with a newer master cylinder and I'm sure something we have dealt with even with the older Suzuki ones begs a question. I'm sure parts will go bad over time but just like changing the brake lines every couple of years, how often should the master cylinder be redone?

As a side note, I rebuilt my rear master cylinder this month as I decided to order a new push rod and a replacement boot (the old one ripped) and found it was pretty nasty inside. I last did that one in 2010.

 

[bwringer]

If you flush the fluid every year or two and keep the brake dust reasonably cleaned out, the brake components will last essentially forever.

I have over 125,000 miles on my '83 GS850, and the front calipers and master have never been apart.

Suzuki's recommendation to replace the brake lines every four years is lawyer BS, but if you replace the rubber brake lines with stainless braided lines (they're actually teflon inside with a braided stainless steel covering) the lines will last indefinitely; there's no need to replace them unless they're damaged.

Once you've upgraded the brake lines, the only scheduled maintenance is to flush the brake fluid every two years (I do this yearly), inspect regularly, and keep things reasonably clean.