Front brake disc problems.
The front right brake caliper from a VFR400 will fit a Bros, the only difference
is the pistons are smaller.
Common faults with the Bros front brake disc.
- Brake pulsing: Brake pulsing is best detected buy speeding up 50Km/h and then
braking fairly hard until you come to a complete stop, as your speed dropped
below 10Km/h you might notice the brake pulsing, as if the brake was coming on and off,
on and off. This is posiblely caused by uneven wear patterns on the rotor,
or the brake disc might be contaminated with some type of grease.
The way to detect this is to remove the brake disc and write the numbers 1 to 10 on the
rotor beside each rivet. Measure the thickness of the disc at each rivet using a micrometer,
in my expeirence a difference in thickness of just 0.04mm is enough to cause brake pulsing.
Uneven wear patterns can be caused by:
- Improperly installed front wheel, brake disc or caliper.
- Loose fasteners.
- Warped brake disc, Honda recomend that the warpage not exceed 0.3mm.
- Mis-aligned brake caiper. Their are many ways of checking caliper alignment, the way I
used was to insert a 6mm rod into the brake pad pin hole and inserting another rod into the
the front wheel axle and then checking that they are paralell.
- Worn or defective brake pads.
- Brake drag can casuse uneven wear and excessive heat (service that caliper).
- Excessive wear: if the min thickness of the rotor drops below 4mm then it should be replaced.
- Scoring on disc or brake pads: Most scoring on the disc is harmless but deep and uneven scores can
sometimes produce noise, scored brake pads should be replaced immediately.
- Warpage, 0.3mm limit, The disc should be replaced, severe warpage can cause a pulsing effect
thru the brake lever.