3. New brake pads running on worn/tapered discs will cause softness
until they wear to match and the springiness goes away. Machine
discs when fitting new pads.
4. It is well proven that undersized discs do not cool well and warp
quickly. Do not use when below minimum for safety and legal
reasons.
5. Check master cylinders for residual valves when converting to discs.
These valves are meant to stop air sucking past wheel cylinder cups
but will make discs drag. Early American Corvette calipers can suck
air and therefore need light pressure, special residual valves, all
modern calipers are fine with none. If not sure, do the dripping
bleeder test.
6. Never get any hydrocarbons, oil, kerosene, petrol etc. near brake
parts – brakes use special rubbers, which swell dramatically when
contacted by hydrocarbons. Wash brake parts in Methylated Spirits
or Brake Clean Fluid and lubricate with brake rubber lubricant
(silicon based), or brake fluid during assembly.
7. Fitting new seals to used master and slave cylinders is not always
successful. Bore wear, scratches and corrosion usually mean
reduced life of rebuilds. Buy a new assembly or have yours stainless
sleeved if necessary.
8. Cheap brake pads are a false economy; they wear quickly and do
not stop as well.
9. A reaction disc is a small rubber disc which lives under the head of
the booster output push rod. If this is lost, the brakes will be nearly
uncontrollable with stopping proportional to pedal position, not
pedal effort, sending you through the windscreen at the lightest
touch.
10.With all modified systems, check everything for clearance, through
all suspension travel and lock to lock, particularly brake hoses and
calipers versus cross members and sway bars etc. on lock.
11.When converting a four-wheel drum type car to front discs
(retaining original rear brakes), it is necessary to fit smaller rear wheel
cylinders to reduce rear brake effort, as the front discs are not self-
energising.
12.If not sure, seek the advice of an expert.