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Hi,
Brake Repair is not Rocket Science, it's all very straightforward. But, there are several things you need do properly.
You want the proper Pads. There are lots of Aftermarket Pads which will fit, but really should not be used. If not using OEM Pads, you need to be certain the dimensions are corect. Thickness varies widely among Aftermarket Pads. The correct dimensions are: 12.0mm (0.47') for the Front Pads and 10.5mm (0.41') for the Rears (Standard and 'S' Models). The allowable wear dimension is 2mm (0.08') for both (this is slighty more than the thickness of a Quarter). Also, too agressive a Pad will quickly wear the rotors, often at a rate faster than the Pads themselves. This is problematic because Brake wear and the need for attention is often determined by the Brake Pad thickness. Also plan to replace the Vibration Dampers at the same time as the Pads are changed and use a File to Champfer the Leading Edge of the Pad Material to a 45° angle to insure proper Bedding and Full Facing of the Pads.
For Rotors, these need to be checked for thickness using a Micrometer. New Rotors measure 24mm (0.94') (28mm (1.1') for 'S' Model) for the Fronts, and 20mm(0.79') (24mm(0.94') for 'S' Model) for the Rears.
The Wear Limit is 22.6mm (0.89') (26.0mm (1.02') for 'S' Model) for the Fronts, and 18.6mm (0.71') (22.0mm (0.86') for 'S' Model) for the Rears.
The Rotors should also be checked for Lateral Runout (warping) using a Dial Indicator. This is very important. Maximum allowable Lateral Runout is 0.03mm (0.0011') for the Rotor alone and 0.06mm (0.0023') with the Rotor Installed (adding in allowable Hub Lateral Runout of 0.03mm (0.0011'). This is important for both proper Pad Wear and reducing/eliminating Vibration in the Brakes.
These tolerances are so tight that Machining is generally not recommended. This is because these tolerances approach the accuracy limits of most Brake Lathes and when trying to eliminate the Lateral Runout - the most important function of machining, you can easily exceed the overall allowable thickness dimension. In either case, there will invariably be a trade-off between Lateral Runout and Thickness.
Also, NEVER use, or allow a Shop to use a Pneumatic Impact Wrench when installing your Wheels. This is because these tools are notoriously inaccurate and inconsistent with the amount of Torque they apply. Today's Rotors are much less massive than years past in an attempt to reduce both Overall and Unsprung Weight. Improper Torqueing of the Wheels Lugs will cause the Rotors to Warp. If using a Shop, do not just insist that the Wheel Lugs be tightened by hand using a proper Torque Wrench, actually Watch them do it!
In addition, before pressing the Caliper Pistons back into the Calipers, these should be inspected for corrosion and if present, the Calipers should be rebuilt. Failure to do this will result in the corroded Pistons Tearing the Caliper Seals and loss of Brake Pressure and Fluid Leaks. Also, the Dust Seals around the Pistons should be checked at the same time.
Flushing the Brake Fluid is also recommended as it will most probably have been in the system for two years or more. There is a different procedure for doing this depending upon if your Car is equipped with PSM/TC or not, so be sure you know the difference.
Finally, it's very important to properly Bed-In your new Pads. If you're not aware of this procedure, search for my thread detailing the proper procedure for doing this. Hope this helps...
Happy Motoring!... Jim'99
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