Broken Brakes

[The Beakman]

When I went to get new rubber put on the bike, the tech showed me I needed new pads in the rear, then some odd wear on the front left pads: the outside left pad is wearing on a bias. If you were to look at the pad straight on (thin-ways) as mounted in the caliper, the top is wearing more than the bottom as if the pad is contacting the disc at a slight angle. This is familiar from the last time I had brakes done but now something new has come up.

I had the shop put new pads on all around and right away on the ride home, and (a little) less so after about 150 miles, I feel what I thought was a rough road surface but is a vibration transmitted up the forks when I engage the rear brake. It is not there or much less prevelant when only using the front lever, and also when braking at high speeds (both lever and foot).

I have no stand or the proper tools to remove any calipers but had a friend work the brakes while I felt the calipers for any odd motion. The left set moved more than the right as only could be noticed by feel, not sight. BTW, left and right as seated on the bike.

Has anyone had a similar problem, or have some insight? If it were just the uneven wear I would say it was a faulty caliper mount first, faulty caliper second but this vibration thing has me baffled for the moment as it involves the linked brakes somehow.

Thanks.

[XXTi]

The left front caliper is supposed to move. That's how the linked brakes work from front to rear. Left front outside pad wear is also common.

I can't comment on your vibration problem though. If it didn't vibrate before the pads, I'd check the installation and make sure the pads are installed correctly. Also check to see that the calipers move freely on their mounting pins. Take a look at the service manual and you'll see what I mean.

[Redbird]

Like Jim said, the "odd" pad wear is normal. It's been noted and discussed here on a couple occasions, most likely a result of the pivoting caliper mount. No real answer as to why it does that, but it no cause for concern

Now, your vibration- Being that you just had your tires changed it's possible a rotor was bent in the process. Simplest way to check is to put the bike on the center stand and rotate the rear wheel by hand, if you feel a stiff spot or hear a difference in the noise the pads make as they lightly drag on the rotor, it's probably a bit tweaked. You can get the front tire off the ground for the same process by having someone (preferably a heavy someone) push the rear of the bike down while it's on the center stand.

[XXTi]

Good point about a possible bent rotor. I change my own tires and sometimes forget that not everyone is careful. Some of the ham handed guys who have the nerve to call themselves mechanics should have their asses kicked.

[The Beakman]

Like Jim said, the "odd" pad wear is normal. It's been noted and discussed here on a couple occasions, most likely a result of the pivoting caliper mount. No real answer as to why it does that, but it no cause for concern

Now, your vibration- Being that you just had your tires changed it's possible a rotor was bent in the process. Simplest way to check is to put the bike on the center stand and rotate the rear wheel by hand, if you feel a stiff spot or hear a difference in the noise the pads make as they lightly drag on the rotor, it's probably a bit tweaked. You can get the front tire off the ground for the same process by having someone (preferably a heavy someone) push the rear of the bike down while it's on the center stand.

Ah-Ha! I never thought to check out the rear disc! And I do think I have a problem there. I shall investigate. Thanks a lot guys.

Good point about a possible bent rotor. I change my own tires and sometimes forget that not everyone is careful. Some of the ham handed guys who have the nerve to call themselves mechanics should have their asses kicked.

The tech semed like a competant mechanic, some 20+ years on the job. But the tires, well they could have been put on by a . . .a . . . some kind of a . . .fucktard!

[Fast Eddy]

Is it possible the new brake pads are "breaking in". I have heard of "bedding in" or the surfaces need to mate. Could this be the case, although with the claim of vibe when braking with rear brakes, def look at rear rotor.