WARNING: This is an easy but dirty job and can pose potential health risks due to the potential presence of brake dust and fluid, so be certain you want to do this job yourself. All modern brake linings are by law asbestos free, but they still create a lot of dust which is best not inhaled. Brake fluid is highly toxic, ingestion and contact with the skin should be avoided. Also make sure you change the pads on both sides of the car at the same time, changing just one side could make your brakes dangerously unstable.
Okay, here goes.
You will need the following items before you begin:
A set of Brake Pads.
A jack to lift the car.
A Wheel Brace to remove the road wheels.
Two axle stands.
A 7mm Allen Key in a socket and a wrench to turn it.
A Torque Wrench
A Flat Bladed Screwdriver
A pair of Pliers.
A large C Clamp.
A wire brush and/or a small stiff paintbrush
You may also want to invest in some strong latex gloves to keep your hands clean and a simple paper mask to avoid breathing in the dust.
Start by making sure the car is on a solid, level surface and that the handbrake is on and secure.
Slacken the wheel nuts on one of the front road wheels and jack up that side of the car. Place an axle stand under the car's body, the correct location for the stand is on the front to back floorpan brace just behind the sill jacking point, and lower the car onto the stand. DO NOT work under the car if it is supported by a jack alone.
Remove the road wheel.
BEFORE YOU DO ANTHING ELSE, inspect the brake disc for signs of wear. Heavy corrosion, deep grooves, cracks or pits in the surface, warping or obviously reduced disc thickness are all indicators that the disc is due for replacement. It is a false economy to put new pads into contact with a badly worn disc, it will wear them out in no time at all.
To remove the old brake pads the brake caliper has to be separated from the brake disc. If you have brake wear sensors on your pads, unclip the connector and wiring and move it to a save position. MAKE A NOTE of the wiring position as only one of the pads has the wear indicators.
On the side of the caliper facing you is a long wire clip that holds in the forward brake pad, grip this with the pliers and prise it free with the screwdriver. Put it in a safe place.
On the rear of the caliper are two plastic covers that protect the ends of the caliper guide pins, remove these.
Using the 7mm Allen key unscrew and remove the guide pins. Some force may be required to slacken the pins.
The caliper can now be pulled away from the disc. Support the caliper on the extra axle stand to avoid twisting the flexible brake hose.
You may find the outer pad stays stuck to the disc, remove this and the the inner pad from the brake caliper piston.
Use the paint brush to clean away any dust and dirt from caliper, you may find a spray-on brake cleaner useful if there are heavy deposits to be removed. Use the wire brush to clean away any rust along the edge of the brake disc, do not use it on the disc surface.
Inspect the caliper for any signs of brake fluid seepage from the piston seal or hose connector. Your new pads will be destroyed if they become contaminated with brake fluid. The caliper will have to be rebulit or replaced if there is a fluid leak.
The caliper piston needs to be pushed back into the caliper to provide enough space for the new pads, this can be done with a C clamp, or if one is not available, a thick piece of wood can be placed between the piston and caliper housing to allow a large screwdriver to be used as a lever. NOTE: brake fluid from the caliper will be pushed back into the brake master cylinder reservoir, care should be taken not to cause this to overflow.
Your new pads can now be fitted into the caliper, make certain you put them in the right way round.
The caliper can now be repositioned and the guide pins replaced. The pins should be tightened to a torque setting of 28Nm or 21lbf/ft. DO NOT overtighten them.
Reposition the sensor wiring, if any, and replace the forward pad retaining clip.
Refit the road wheel and lower the car to the ground.
Carry out the same procedure on the other side of the car.
When all the pads are in place check the brake master cylinder reservoir fluid level. Top it up if it is too low, or syphon off any excess fluid if the level has gone above the MAX marker.
Make sure you test your brakes thoroughly before you go on any long journeys and remember they will take a short while to bed in before they work at their full capacity.
Suddenend, October 2010
