Thursday, December 24, 2009

Christmas Caliper (Non-) Catastrophe

It was an unseasonably warm 56°F when I set out to run some errands on Tuesday. I noticed I was low on gas, so I set out for a quick run to the Lewis Country Store in Scottsboro before swooping back into town for a stop at the public library and Aldi.

Just as I finished the 55-70mph ride up Briley Parkway and Ashland City Highway, and pulled into the gas station, the rear tire locked up as I was slowing towards the pump. "Uh-oh... is that my belt coming apart, jamming in the clutch?" Being thankful that I have my cellphone Just In Case, I give it a little gas. It lurches about 6" forward, and stops, again, bucking like a horse. I get off it... can't even push it.

Closer examination shows that the front bolt that holds the rear caliper to the swingarm has vibrated itself completely loose. If not for the muffler, it would have hit the road some time ago, but as it is, it backs out only as far as the muffler will allow. That distance, however, is sufficient to allow the caliper to clear the threaded end of the bolt (probably designed that way so one can change the rear brake pads without removing the muffler, if one is talented enough).

The end result being that the caliper, now only being held by one bolt, was allowed to pivot on the axis of that bolt, and that last application of the rear brake was enough to cause the front of the caliper body to contact the rotor, which cut into the caliper like a saw blade. Good thing I wasn't going very fast, eh?

As you can see, the end of the caliper where the damage is is now discolored to a bronze-like color, instead of the aluminum color of the rest of it. I hope this does not mean that it is irretrievably damaged. The rotor only has some small nicks in the very edge, and no burrs, so I think it is okay.

The whole caliper, uninstalled. I couldn't get the small wrench I had with me into the tight space to re-tighten the front bolt, and I wasn't going to try to remove the muffler there at the gas station. So I removed the caliper from the rotor, and hung it over my rear passenger footpeg to get it home (it definitely would not have been safe to leave it attached as it was). Today, when I needed to ride again, I removed the caliper, entirely, to prevent further damage to it or the brake line.

UPDATE: Now that I think about it, I wonder if this hadn't been going on for some time, and it only getting burred enough to catch when I noticed it. Look at my mileage chart at Fuelly. If this had started between 11/11-11/15, that would make some sense, wouldn't it?


  1. Dang, that is fugly. I'm kinda glad my Helix has a rear drum.

  2. Well, I wouldn't go that far. :) The disc is a much better brake, and this one got a good 'un. It probaby should have had some blue Loctite applied before being reassembled, and I will certainly do so when *I* reassemble it.

    If the weather holds, I'll do that tomorrow at the shop.