This procedure was lost with the old forum, but has saved many Coupe owners a lot of money, by preventing the replacement of "warped" discs that weren't actually warped.
The cause of brake judder isn't actually a physical warp in the disc - its an uneven build-up of pad material on (in) the disc surface. Often, the effect is felt as an on-off-on-off feeling when braking really gently, rather than a violent judder from high speeds.
When a disc gets hot, pad material is chemically transferred into the crystalline structure of the disc material. This is the purpose of bedding-in - it deposits an even amount of pad material around the disc.
The on-off-on-off feeling is actually caused by one section of the disc being "grippier" (or occasionally, less grippy)than the rest of the disc. This is caused by the pad material being deposited unevenly around the discs.
There are two reasons this:
1) Wearing away of the original bedding-in process pad material, leaving some of the disc surface with less pad material than others - this is most commonly caused by prolonged periods without heavy braking (winter?)
2) Excess material being deposited on one part of the disc - almost always caused by coming to a complete standstill with the brakes on when they're very hot.
In either event, the procedure is the same:
From Pagid's own bedding-in procedure:
Basic bedding-in:
4 - 6 stops with medium brake pressure from about 90mph to 50mph - distance between stops about 300 - 400m
Immediately after basic bedding-in:
One stop with medium to heavy brake pressure, from 110mph - 50mph
then 3 - 4 "recovery" stops using "basic" method.
Repeat the big stop and 3 - 4 light stops a further 2 times.
Important
NEVER come to a complete stop when bedding-in - it will ruin your hard work
NEVER get the ABS to cut in - its the same as coming to a complete stop
ALWAYS allow about 500 metres after a big stop to let the brakes cool a little (Pagid suggest 500m - I suggest double this, as Coupe's brake cooling is awful)
Given the speeds mentioned above (the process is designed for the track, not the road), I strongly suggest you only ever perform this procedure on your own quiet stretch of (ahem) private road
Once you've conducted the bedding-in procedure, drive for a good few miles to let the brakes completely cool down before stopping the car.
Many sets of discs have been saved with this method - its always worth a try, as there is absolutely nothing to lose (apart from your licence, if you try it with Plod around )
Courtesy Nigel
