Sticky rear brake on a K4

The rear brake was sticking and the disc was very hot on Monday. I took the rear caliper apart and had the piston almost out but it was clear that it was in fine condition with no corrosion (yes, this IS on a Suzuki) so I didn't take it all the way out.

I reckon it's the brake fluid (never been changed). The pedal goes down and then doesn't come all the way back up, unless I hook my boot underneath and give it a final pull up.

Anyone who's had problems with brake pistons - if the piston is the problem, it'd be obvious that there was corrosion, etc. on it, causing it to jam, no?

I'll change the fluid tomorrow, weather permitting, and see if that makes any difference.

Before you start messing with the hydraulics, take the lever/footrest assembly apart and grease all the mating surfaces.

[jambo]

Originally Posted by Carsick

Before you start messing with the hydraulics, take the lever/footrest assembly apart and grease all the mating surfaces.

However shot the caliper piston and fluid is, the lever will always return smoothly unless there is a problem with the lever pivot or master cylinder. I'd go with Carsick and say that dirt / salt / crud has stopped the brake lever pivoting properly.

Cheers guys, that was exactly the problem. Took it apart, cleaned it up, blasted it with WD40 and it's better than it's been for months. Saved me hours mucking around changing the fluid and not sorting it. Another year with the same brake fluid beckons...

I'd suggest using a proper grease to save you the hassle of having to do it too often. I think white grease works well.