How to adjust the rear brakes on my mountain bike?

it has rear calipers. i dunno the name of the type of calipers but it looks like the ones in the pic, but just a bit different, cause its an older bike.


http://www.cyclesuperstore.ie/shop/pc/ca...

btw, can i change the brakes on my bike from calipers to disc brakes? if so, what would i have to do? how much would it cost me?

Those are called sidepull brakes. Here are the directions to adjust them as well as they can be, but I am guessing that the brakes are made from stamped sheet metal and will never work well. This is a little long so bear with me...

1) Adjust the brake shoes. Loosen one shoe at a time (probably a 10mm wrench DO NOT USE PLIERS), pressing the caliper in so the shoe contacts the rim. Center the shoe onto the rim and retighten. No need for the Power of Atlas when tightening... just 1/2 turn past snug is all you need. Align all shoes.

2) Loosen the cable fixing bolt (again, probably a 8mm, 9mm or 10mm wrench). Squeeze the shoes against the rim with one hand, then pull the end of the cable with a pair of pliers. While still holding the calipers in place tighten the fixing bolt. Again, no need for overtightening.

3) Squeeze the brake lever HARD a couple of times. Then, as you are operating the lever check to see if both of the caliper arms are moving equally. If NOT, "tweak" the nut (probably 10mm) that holds the brake onto the bike until both arms work. You usually don't have to loosen the nut... just "help" the caliper to center while moving the nut. Repeat as necessary. This takes a bit of time when you first try it and can be a hassle.

I can tell you without reservation that it will cost you a LOT more than the value of your bike to add discs. You'll need disc compatible hubs, disc compatible brake levers, discs, calipers, cables, not to mention the requirement that your frame has to have disc brake mounts which I am certain it doesn't. However, if it DOES have mounts, figure a minimum of $300- $400 for mechanical discs and all the fixin's.