Follow these instructions if your calliper brakes clog with road dirt, if the brakelevers stick or if the brake doesn’t return smartly when you release the brake-lever.
Always do one brake at a time – that way, you’ve always got a complete one to refer back to if you get stuck in the middle of reassembly. Take particular care to clean road grime away from around the return spring. There isn’t much of a gap between the spring and the calliper arms, so it doesn’t take much of a build-up of detritus to make everything feel sluggish. For the full spring clean effect on tired brakes, combine this service with a new pair of blocks and a new brake cable. Once you’ve got all your tools out, it doesn’t take much longer to do the whole lot at once, and you’ll feel the difference in increased braking control straight away. Fresh brake blocks are easier on your rims, minimising wear so that they last longer.
Step 1 : Start by cutting off the cable end on the brake cable, undoing the cable pinch bolt and pulling the brake cable and casing out of the barrel-adjuster. If you’re thinking of fitting a new cable or cable and casing, do this now by following instructions.
Step 2 : Undo the bolt that attaches the calliper to the frame/fork. It’s either a 5mm Allen key or a 10mm nut. If you’re doing both brakes at once, don’t get the front and back mixed up – the pivot bolt that sticks out of the back of the front calliper and through the fork is slightly longer. Clean and inspect the fixing bolt – the 5mm Allen key type is called a sleeve nut – for cracks. Clean and inspect the bolt hole.
Step 3 : Turn the calliper over and have a look at the back surface. You don’t usually get to see this side of it and it tends to collect grit. Clean it thoroughly with degreaser or bike wash and a scrubbing brush. You can see the return spring clearly from here. Get right in close and clean up all around it so it can move freely. Squeeze the brake blocks together a few times to work out stray bits and pieces of dirt or grit.
Step 4 : Turn the calliper so you can see the top and give this a good scrub, too. Again, squeeze and release the calliper and clean all the bits that squeezing it reveals. Once the whole calliper is clean, rinse off all the degreaser. Drip a little drop of oil down into the gaps between each part of the mechanism and squeeze the calliper to work the oil in. Wipe off excess – it will only collect dirt. The calliper should feel much smoother.
Step 5 : Pop a drop of oil on the calliper fixing bolt and slide the bolt back through the frame/ fork. Make sure you replace any washers that sat between the calliper and the frame. These are there to stop the back of the calliper getting jammed on the frame/fork. Refit the fixing bolt.
Step 6 : Hold the calliper as shown so the wheel runs centrally between the blocks and tighten the fixing bolt firmly. Wiggle the calliper to check the fixing bolt is secure – otherwise it will work itself loose. Feed the brake cable back through the barrel-adjuster then under the pinch bolt washer. Hold the blocks against the rim, pull through any excess cable and tighten the pinch bolt firmly. For final cable adjustments.
“Fresh brake blocks are easier on your rims, minimising wear so that they last longer”
Source : BIKE MAINTENANCE TIPS, TRICKS & TECHNIQUES