Why are my Kawasaki ZR7’s brakes playing up?
Q. I have recently had my Kawasaki ZR7 serviced. The front brake was playing up and new pads were installed to restore service. But my brakes are still in a bad way – there is so much travel in the lever it almost touches the bar.
The mechanic told me that when the pads wear in it would settle down. But I am not sure I believe him as I have had lots of bikes and never experienced this problem before. Is there anything I can do? Is he right?
A. No he isn’t right. I don’t think he’s serviced the brakes properly as there's a sequence of checks you need to go through. Is the brake fluid fresh? If it's three or four years old it needs replacing. When the new pads were fitted did the caliper pistons get cleaned up?
For the last few thousand miles of the previous pads' life more of the pistons will have been exposed to the elements. If they weren't cleaned properly before the new pads are fitted, the pads push those dirty pistons past the caliper piston seals, possibly contaminating them and making them stickier.
What happens then is that the pistons are pulled back too far off the pads by the 'sticky' seals when you release the brake, giving you excessive travel. If that all stacks up, you're looking at the master cylinder piston seal, or maybe, just maybe expanding brake lines.