[200q20v] bedding brakes - the real reason

[Glen Dustin Powell]

The reason to bed new brakes is to permit controlled outgassing of the pad
material. If you heat the pads up too hot too fast the molecular structure
of the pad material is torn apart and is damaged permanently. The idea with
bedding is to bring the pads slowly up to a high temperature over a period
of time, hence the '3-5 repeated but gradual stops' frequently suggested
(but inadequate in most cases). Generally performing many repeated moderate
stops from like 30 MPH and slowly increasing the speed and agressiveness
until the pads are 'stinky hot' and just starting to smoke a bit is a good
procedure to use. Bring the car slowly back up to speed before the next
application to allow for some cooling a an overall controlled increase in
pad temp over time. Get out after every few stops and feel the temp of the
inner area of the wheel where it bolts to the hub, smell the brakes and
observe for smoke. When the wheel is hot and you have visible smoke coming
from the pads put a fork in 'em - they're done! Should take about 5 mins to
slowly approach stinky-hot & smokey. A laser-pointer non-contact temp meter
is very handy here to monitor progress if you have access to one. A
secondary beneficial effect of brake bedding is letting the new pads get
friendly with the new or used rotors surface-wise, but this is not the
primary reason for bedding. Some new race pads are of a material that
requires no bedding/controlled outgassing, but these are the exception and
not the rule.

I do like that technical term 'stinky hot' a-lot....

-glen