| Most of us know that the fluid in the brake and clutch hydraulic system needs to be changed every couple of years or so, but do you know what happens when you really neglect it?
There’s a good reason why changing brake fluid every couple of years is in every manufacturer’s maintenance schedule: it absorbs moisture.
Over time the moisture level increases, which lowers the boiling point of the fluid. This isn’t noticeably a problem until one day, descending that long hill with the brakes applied, the fluid temperature exceeds its boiling point and air bubbles form.
The worst-case scenario is that the brake pedal immediately sinks to the floor and the brakes fail. At the very least the pedal action becomes ‘spongy’, with little resistance, and poor brake performance.
If the fluid is left unchanged for a long time, it turns into a thick syrup, then eventually into a crystalised gel.
I’ve just dismantled a motorcycle that’s been stored in a garage for a few years. The brake just about still worked, but the front calipers were slow to release.
After splitting the calipers, this is what I found: a thick syrup... | 
