[Darkreaper]

Ok, so I went away for two weeks, and someone else was riding my bike. Now I'm home, and the front brakes have lost a lot of their stopping power. They're Hayes mechanical discs, and they used to be so strong that with the brake on even jumping on the pedal wouldn't move me, and I could stop in a very short distance.

Now I can't get the same 'locking' effect I had, and the overall performance just sucks. Full lock and the wheel still spins when enough pressure is applied to the pedals. I've wiped the disc with paper, and run paper through the calipers to make sure there's no mud on the pads. I've had the bike since October now.

I know there are probably loads of ways that it could have gotten screwed up. What I want to know is what can I try to do to fix it, short of buying new pads (and would that even work? It could be the disc, right?) My disc also seems to be out of true when I spin the wheel but it's been like that a while.

Cheers

 

[Kornphlake]

it sounds like your pads got oil on them, in which case you really can't do anything but get new pads. You can use brake rotor cleaner available at an auto parts store on the rotor, or just use alcohol but there's no way to salvage the pads if they've been contaminated with oil. Some people claim that you can soak the pads in alcohol, boil them, bake them or barbecue them (I'm not kidding I read about someone doing this) the idea is that you can evaporate, dissolve or burn the oil out of the pads but this just isn't true. And don't think you can use brake cleaner on the pads, break cleaner was designed for automobile brake pads which differ from the type used on bicycle brakes.

I'm guessing you've already adjusted the brakes so the caliper is centered correctly and such so I won't mention that.

As far as the bent rotor you can put a crescent wrench on the bent part of the rotor and gently bend it back, I've found that my rotors are slightly out of true as are most. Unless your rotors are really out of whack trying to straighten them will most likely make them worse.

 

[rpk1988]

You were letting someone else ride your bike....thats a no no in my book. Unless its not my bike....

 

[Darkreaper]

It's my bike - but I couldn't bear the thought of it sitting alone in a shed over winter... So rubbing alcohol or something will clean the rotors?

The problem with the rotor being out of true is that it then rubs on one of the pads, and the noise gets annoying after a while. I can't stop it unless I open the pads so wide that I lose braking power.

 

[Kornphlake]

One other thing you could try is to run the bike down a long hill with the brakes dragging pretty hard so that the rotor gets hot then let it cool down slowly, or if that doesn't work ride back to the top of that hill, drag the brakes down and then dump your camelback on the rotor so it cools quickly. The rotor might warp itself back if the warppage was caused by some thermal shock, unfortunately every time you get the rotor heated back up it will settle back into it the same place. I've never seen a bike where the rotors were completely true, some are much worse than others though and you might have just gotten a bum rotor.

One other thing that may have happened is that the pads got glazed. I haven't read about this in a long time, as I recal there were only a hand full of pads that this would happen to. The solution was to remove the pads and gently sand them with a piece of sand paper wrapped around a block of wood or something else flat untill the glossy finish all gets sanded off.

 

[Darkreaper]

I'll try the hill thing on my way home today. 1.5 miles of hill should be enough, right?

If that doesnt work I'll just get new pads. How hard are they to replace? Can I do it myself easily enough?