When I pull the right lever to brake I notice that it is not smooth. It's almost as if the part that the lever pushes in the master cylinder needs lube. It is part number 3 I am referring to in the microfiche below. Would changing out the fluid alleviate this? Thanks!
changing the fluid won't by itself help that but you should do it anyway, Brake fluid needs to be changed occasionally (sort of like engine oil does even in an engine that doesn't get run much) because it picks up dirt and moisture that over time causes corrosion. You may just need a little silicon lube in the plunger. But if that doesn't work, you're too far gone for a simple fluid flush to cure it. You will need to rebuild the master cylinder and inspect the piston for corrosion. If you or previous owner never flushed the brake fluid, that piston could be what's sticking. And if that's it, don't stop - the caliper(s) need rebuilt too.
Ok, I'll try a little WD-40 in there. Does the diaphram and the spring reside in brake fluid? (Part 2 of the microfiche)
Dont use any oil based lube, only use a drop of clean brake fluid or synthetic lube, oil base lubes and brake fluid react to each other.
We're not talking about lubricating inside the brake fluid. Smear or squirt something inside Boot part #3 (I use silicon grease, there's stuff made specifically for brake parts) and see if that changes anything. On the diagram, the cylinder with the rings is the piston, and the rings are seals - going towards the snap ring, it's brake fluid on the inside, atmosphere on the outside, which is semi-sealed off by boot #3 (diaphragm). But that's not a great seal, and no that is not what holds in the brake fluid. So the piston slides, partly in and partly out of brake fluid, but you don't know what is catching. Hence the squirting in of lube - if that helps great, if it doesn't, it's rebuild time. If your o-rings are at all functional (and if your brakes work, they are) lube is not going to get into the brake fluid.
Thanks for the replies all. 2wheelsrbest had it, it was the lever pivot. I was so sure it was the other part.
