Fred
M em b er e d
So I noticed that there was a strange wear pattern on my rear brake rotor. There was a rough bit near the outer edge, like something was rubbing.
Sensing a problem, I began to take the rear caliper off. And here's where I made a mistake.
To get the caliper off, you only need to remove the rear, 10mm bolt. The front 14mm bolt does not need to be removed. I know this now.
I was unscrewing the front bolt, and it was coming out, and then it got stiff. So I stopped. I tried to turn it back in, but it was stiff in that direction too. Not good. The bolt had seized against the threads.
So with the bolt halfway in and halfway out, there's really nothing to do but get it all the way out. It's painful, because you know you're doing damage. But if you don't, you're not going to be able to fix anything.
So I got a cheater bar and used more force, and got the bolt out. Here's what I found.
That's the hole in the caliper. The innermost 1/3 of the threads are intact, but the rest are gone.
So where did those threads go? Found em!
Ugh. I need a new bolt, and I need to repair the stripped out threads in the caliper. So much for going for a ride tomorrow.
And what was causing the wear to the brake rotor? Here's the culprit.
The circle is around the spot that was causing the problem. It's an larger than normal chunk of copper that is embedded in the brake pad material. The pads are sintered metal. This piece of metal is bigger than it should be and is casuing abnormal wear on the rotor.
Anyway, the lessons for all of you.
1. Watch for abnormal wear on your rotors.
2. You should NEVER need to remove that front bolt. Remove the rear one and the caliper will swing up and then slide off to the right side of the bike.
3. Any time that you have a steel bolt going into aluminum, hit it with some penetrating oil and let it soak in for a while before you try to remove it. What happened to me, I'm sure, is a small speck of grunge or corrosion on the steel threads jammed up against the softer aluminum. As I kept turning, it picked up aluminum like a snowplow, making the problem worse and worse. And by the time I felt it, the torn out aluminum was big enough that I couldn't turn the bolt back in past the innermost, intact threads.
I made a choice between tearing out the inner threads (and having a stuck bolt) and tearing out the outer threads and getting the bolt out.
It's not terminal, but it sure is a pain in the ass. I'll need a thread repair kit, a new bolt, and new brake pads to fix the problem.
Fred
Sensing a problem, I began to take the rear caliper off. And here's where I made a mistake.
To get the caliper off, you only need to remove the rear, 10mm bolt. The front 14mm bolt does not need to be removed. I know this now.
I was unscrewing the front bolt, and it was coming out, and then it got stiff. So I stopped. I tried to turn it back in, but it was stiff in that direction too. Not good. The bolt had seized against the threads.
So with the bolt halfway in and halfway out, there's really nothing to do but get it all the way out. It's painful, because you know you're doing damage. But if you don't, you're not going to be able to fix anything.
So I got a cheater bar and used more force, and got the bolt out. Here's what I found.
That's the hole in the caliper. The innermost 1/3 of the threads are intact, but the rest are gone.
So where did those threads go? Found em!
Ugh. I need a new bolt, and I need to repair the stripped out threads in the caliper. So much for going for a ride tomorrow.
And what was causing the wear to the brake rotor? Here's the culprit.
The circle is around the spot that was causing the problem. It's an larger than normal chunk of copper that is embedded in the brake pad material. The pads are sintered metal. This piece of metal is bigger than it should be and is casuing abnormal wear on the rotor.
Anyway, the lessons for all of you.
1. Watch for abnormal wear on your rotors.
2. You should NEVER need to remove that front bolt. Remove the rear one and the caliper will swing up and then slide off to the right side of the bike.
3. Any time that you have a steel bolt going into aluminum, hit it with some penetrating oil and let it soak in for a while before you try to remove it. What happened to me, I'm sure, is a small speck of grunge or corrosion on the steel threads jammed up against the softer aluminum. As I kept turning, it picked up aluminum like a snowplow, making the problem worse and worse. And by the time I felt it, the torn out aluminum was big enough that I couldn't turn the bolt back in past the innermost, intact threads.
I made a choice between tearing out the inner threads (and having a stuck bolt) and tearing out the outer threads and getting the bolt out.
It's not terminal, but it sure is a pain in the ass. I'll need a thread repair kit, a new bolt, and new brake pads to fix the problem.
Fred
