Master Cylinder Rebuilding - When?

[rcoville]

Is there a general guideline on when you should consider re-building your master cylinders? Obviously if they start leaking or bleeding off pressure that's a sure sign. But how about age guidelines? With these classic bikes, should something pre-emptive be considered BEFORE they start to act up? Opinions?

[mike_of_bbg]

The GS550 factory manual says the master and calipers should be rebuilt every 2 years. I've seen the same quoted as a replacement interval for the brake lines on this board - though the GS550 manual does not say that.

[Dogma]

Try this perspective: Is it worth your time to know your brakes aren't about to fail? Or, do you know that it hasn't ever had the same fluid in it for more than a year or two? More than likely, your masters and calipers all have some sludge in them at this age. If you wait for symptoms, they can come in the form calipers dragging hard enough to use up your traction reserve in a turn. In other words, please do it preemptively.

It's actually not that hard. The hardest part is finding snap ring pliers long enough to reach the snap ring in the front master. I think Motion Pro makes one. I made mine from a pair of needle-nose pliers on the bench grinder.

For a braking upgrade convert it to braided stainless. If you use Earl's DIY parts, you can do that ES, including the anti-dive, for a bit over $100. Much firmer lever, and better braking power (effort not wasted stretching rubber lines). Also not difficult. Search the forums here to find out how.