5 THINGS YOU NEED TO KNOW
1 CALIPER PISTON
These sit in bores held in place by a rubber seal recessed into a groove in the caliper body. As the pads wear, more of the pistons’ surface is exposed to corrosion, which can cause them to stick. They should only be cleaned with dedicated brake cleaner – other products like WD-40 can make the seals swell.
2 BRAKE PADS
Organic pads are for small-capacity bikes, and use a cocktail of aramid fibres, rubber and copper strands. Sintered pads have better wet-weather performance. They have a stronger initial bite, don’t take long to bed in and last longer than organic pads. The material is a mix of copper, tin, carbon and Mullite (a high-performance ceramic material).
3 BANJO UNION
A hollow perforated bolt passes through a spherical union carrying the hydraulic fluid into the caliper body. The union has a long neck which looks similar to a banjo. New crush washers should be used each time they are fitted to avoid leaks.
4 BLEED NIPPLE
A threaded screw mounted into the top of the caliper that allows any build-up of air to be ‘bled’ out of the system after servicing or dismantling. As air compresses its presence means that hydraulic pressure is lost while it’s squeezed, which reduces ultimate braking power and affects feel. 5
More rigid than axial set-ups because the bolts are perpendicular to the wheel’s rotation and not parallel to the axle, cutting down on deflection. They can also be made from a single block of metal and run larger pistons. They can accommodate larger discs on race bikes easily too.
Much more useful than the musical banjo!
Keep pistons and seals clean to ensure top stopping power