Well, I officially went on my first ride yesterday... and was disappointed to find a few problems with my bike...

1) The rear tire is screetching when I brake...

2) my rear brake pedal is a soft - I pressed down on my fellow riders rear brake it was solid (meaning I could feel that the brakes were being applied and I should stop putting more force on it)
He suggested that there was air in my rear brake lines and I should drain + refill it...

Any suggestions/ideas?

thanks.

Screeching when braking sounds like you need new pads.  It's probably a good idea to change the front pads as well.

Try bleeding your line like the other guys said and see if that helps.

Theres only 5500km on my bike, and the pads don't look worn out... they looked better than my friends bike which had 10K+ on it..

Would this be the most obvious reason that its screeching?

Could the 2 symptoms be related?

Yeah, you should check your pads and replace them if they're worn. Also make sure your rotor is to spec meaning it isn't too thin and there aren't any grooves in it that you can catch a fingernail on. Basically, if you can feel any grooves, it is too grooved. If the rotor is shot and you replace the pads without replacing the rotor, you'll just have to replace the pads again when you get a new rotor, so it is much better to do them both at once.

As for the soft pedal feel, you need to bleed your brakes. Just get a fresh bottle of brake fluid (you can't use one that's been opened, it absorbs water and goes bad really fast) and one of those vacuum brake bleeder pumps. Just take the cover off the reservoir under the seat, connect the pump to the bleeder on the caliper, crack it open and add fluid to the reservoir as you pump it out of the caliper. Don't let the reservoir get empty, you'll suck air in the system and that's counter productive. Once the brake fluid coming out of the caliper is clean and bubble free, close the bleeder, top off the reservoir and you're done. Whatever you do, don't spill brake fluid on anything, it eats paint better than anything else I've ever seen. Also make sure to dispose of the used brake fluid properly. You'll probably have to go to your local hazardous waste center to get rid of it.

You could also search for Kerry's post on brake bleeding, I'm pretty sure he posted a really detailed set of instructions with pictures and everything.

Quote from: joepua on March 23, 2009, 10:04:55 AM
Theres only 5500km on my bike, and the pads don't look worn out... they looked better than my friends bike which had 10K+ on it..

Would this be the most obvious reason that its screeching?

Could the 2 symptoms be related?

Brake pads aren't rated for any specific distance. Their wear is directly correlated to how you use them. If the previous owner rode around with the brakes on all the time or liked to go to the track, he could have killed the pads in way less than 5500km. Also, the screeching can be related to the vibrations between the back of the pad and the piston. There are many products on the market sold to minimize this problem. You just apply them to the back of the pads when you install them and they help keep the brakes quiet. Another possible source of screeching is a grooved rotor, so check that too...

Fred, how does he have such problems with so few miles?  That bike should still be good as new.  He definitely needs to bleed the brakes, but half the cars and bikes I've owned had brakes that squeal, even with new pads and rotors.  I say ignore it.  How he has air in the line at this stage of the game is also a mystery.

Pads even when new can make noise if the mechanic contaminated the pads or the pads have cracks in them I have seen it both on cars and bikes. Its not uncommon to have bad pads if they are the cheap brand. Air can get in if the previos mechanic did a shotty job again not uncommon.

My bike even when new from the stealership had the rear squeal.  I searched the boards soon after and it seems like a common enough problem. For me personally it goes away, and comes back sporadically. I'd say check them just in case and if not worn then ignore the noise

I am going to bleed the lines and go from there...

it just sucks... 5500km and screeching its strange though, the screeching only happens if I am traveling @ low speed, I dont know if thats strange but... lol..