Personally replacing the brake pads on your Opel Astra will save you hundreds of dollars. Aside from the savings, you will also get the satisfaction of repairing your own vehicle. When replacing the brake pads, it is recommended to replace the rotors as well, so that the new brake pads have an even surface to push against during braking. Replacing the brake pads and the rotors will increase performance and longevity of the brakes.
Lift the Opel Astra with the jack and place it on jack stands.
Remove the wheels with a lug-nut wrench and set them aside. The lug-nut wrench can be found in the boot of your Astra. If you cannot find it, you can also use a ratchet and a 19mm socket.
Remove the caliper with a ratchet and use a bungee cord to hang the caliper. Do not let the caliper hang from the brake hose, as the hose might break and cause fluid to leak.
Remove the brake caliper bracket from the steering knuckle with a ratchet and set it aside.
Remove the brake rotor from the hub. The rotor might require force to be removed; if it does, use a hammer to hit the rotor in the centre, where the lug studs are located. Take care not to hit the studs.
Remove the new rotor from its packaging, and use brake cleaner to remove the grease from the rotor. Grease is applied on the rotor in the factory to inhibit rust during storage.
Install the new rotor onto the hub.
Install the caliper bracket with new brake pads onto the rotor and fasten it to the steering knuckle. Use a ratchet to tighten the bolts.
Open the master cylinder reservoir, so that you don't break a seal while compressing the brake caliper.
Compress the brake caliper with a C-clamp, so that the caliper can fit over the new brake pads. Install the caliper by securing it to the brake caliper bracket with a ratchet.
A brake caliper compressor might work better for you than a C-clamp.
Wear safety glasses while working on your brakes.