cyclopticgaze
Brake Job on the WRX (Front)
Mar 28, 2009
Normally, I only talk about one car here, but the fact of the matter is that I drive something completely different on a day-to-day basis. It's time to swap out the snow tires on my 2005 WRX for it's usual all-seasons, and the mechanic noted on its last service that the brake pads are getting thin. I also plan to track the car soon, so let's trade out the old, stock brake pads for some new ones while the wheels are off.
Up on a jack stand, I pulled the wheel off and this is what we see. It's a two piston caliper, and we need to move it out of the way to gain access to the pads.
Two 14mm bolts on the inboard side hold the caliper. Rather than completely removing the caliper, I removed the bottom bolt, loosened the top one, then rotated the caliper up. Here, a length of wire keeps the caliper up and out of the way while I work on the pads.
The brake pads simply slide out perpendicular to the rotor's surface. Here, I've removed the outboard pad and I'm using a small flathead screwdriver to pry out the inboard pad. I was gentle not to mar the rotor's surface.
You can clearly see the difference in thickness between the new and old brake pads. The new pads are Hawk HPS, which should provide better grip than the stock pads. HPS = High Performance Street, so they ought to also have a good lifespan and give off little dust, making them also good for street use (which is 98% of my driving).
There are clips that sit in the caliper above and below the brake pad that hold the pad in place. I've pulled the bottom one out to clean it off and grease it up.
A little brake grease at the heavy contact points will help keep the brakes from squealing. I flipped this clip back over and pressed it into place. Same thing up top.
The backs of the new brake pads get a thin coat of grease, too. After coating the pads, there are some thin plates that get pressed onto the back of the new pads. I've used the original hardware here; some brake pad kits will include new parts, but mine did not. A true mechanic would clean these off with brake cleaner, but I just dry scrubbed them with some steel wool. I figure that they're still cleaner now than when they came out.
Take care not to get grease on the contact surface of the pads or on the rotor. It'll surely burn off the first time you stand on the brake pedal, but it's just good practice not to lubricate your brakes.
I slid the new pads in from the sides the same way that the old ones came out. The clips should hold them in place.
At this point, it's time to pop the hood. I found the brake fluid reservoir and simply unscrewed the cap. Because the old pads are really thin, the brake caliper's pistons are pushed pretty far out. I need to push the pistons back in to fit the new, thick pads. Uncapping the reservoir opens the hydraulic brake system and will let the pistons move when I push on them. If I didn't open the system, I could push and push on the pistons, but the pressure in the system would mean that they wouldn't budge.
To retract the pistons, you can either push really hard, or do it the easy way. I took a clamp and used it to squeeze them back. Here, you can see the difference between an extended piston and one that I've retracted using a bar clamp.
As I retracted the pistons, I checked the brake fluid reservoir to make sure it wasn't overflowing. The fluid level will go up as the pistons get pushed in. If it overflows into the engine compartment, it'll eat away any paint it finds (ask me how I know *cough* 2002 *cough*). If the level's too high, in the past I've successfully used a turkey baster to suck fluid out of the reservoir.
With both pistons retracted, I undid the wire and rotated the caliper back down into place. It's a tight fit with the new, thick pads, and I had to do some good banging with a rubber mallet. I replace and torqued the two 14mm bolts that hold the caliper to the car and put the wheel back on. This side's done, time for the other side.
Coming soon, the rear brakes. (I had to quit early to catch the UConn game.)