DIY: 06-07 WRX brakes for your 04-08 Forester! An OEM brake upgrade for your Rally wheels!
With all the newest performance and sport version cars being equipped with a Brembo brakes you can often feel left out with the Forester’s little two piston front brake and one piston rears. Well, why not do something about that and keep it oem while we are at it!
Subaru introduced the front 4 piston and rear 2 pistons with the 06-07 WRX in America. Why didn’t they add them to other performance models… Outback XT, Legacy GT, Forester XT, etc… who knows but they are quite a great upgrade to the factory Forester brakes. While the front brakes bolt right on, being a simple task for those versed in brake replacement. The rear set will need either a WRX rear knuckle or the proper brake adapter kit to situate them on the Forester knuckles, along with a bit of dust shield modification to fit the new larger rear rotors. One other bonus of these brakes are they work well with 15” gravel wheels to tear up the rally-x course.
What tools will we need to complete this task? You will need a lug nut socket and ratchet/impact gun. A 14 mm and 17mm socket. Brake line wrenches 10, 12 14mm for the bleeders and lines/hoses. If you install the the hub adapter you will need a 10mm allen socket too.
These are my stand by hand tools. I have used these sockets for the last 6 years without breaking one. I really enjoy them. The wobble extensions will help you get into those hard to reach places where there are many on your Subaru. The pliers set will help remove those tricky stuck breather hoses.
Parts we will need are front and rear brake pads for an 06-07 WRX, choose your favorite company and style of brake pad from street to track. The factory Forester brake lines will fit, but you can replace them with the 06-07 WRX brake lines that have locating tabs to keep them in place when tightening down the banjo bolts. If you purchased 06-07 WRX rear knuckles you will bolt them straight on, if not have your adapters ready to go. 06-07 Wrx front and rear brake rotors are larger than the standard Forester units, so add those to the list. A few quarts of your favorite brake fluid will be needed to purge the system of air and replace the lost brake fluid.
As with most projects we will start by lifting the vehicle off the ground and remove the wheels. Set the wheels aside and in a safe place for you to work on the car.
Now you can began at either end of the car you like, I generally start on the front as it is a bit less work and gets your project off on the right foot. The only difficulty on the front brakes are the lower strut bolt, it can hinder the removal of the upper brake caliper bolt. Sometimes you can sneak it by and other times it is just worth removing right away so we don’t struggle with it.
With that dealt with we can loosen the brake hose banjo bolt. You will thank your future self for breaking those loose prior to removing the brake caliper, otherwise prep yourself for a struggle! Now you can break the two caliper bracket bolts loose and free them from their brake caliper prison. Now you can pull the caliper away and remove the banjo bolt.
Next the brake rotor will need to be removed. I generally bust out the BFH or big flippin’ hammer to smack that guy right off. If yu are trying to save the rotors for another project or a back up. You can use bolts to drive it out that are located in between the lug studs. Otherwise you can bring out your brass hammer or rubber mallet to give it a few good strikes and remove it.
The bigger rotors are up next and you can place them on the hub. Next the brand new flashy caliper is ready to go on. You will easily slide it over the rotor and place the two caliper bolts in. With it held in place you may now install the brake hose with two new crush washers and The banjo bolt. The brake pads can slide right in and get cozy in their new home.
Having installed the pads you can now attach the supplied hardware. Slide the two caliper pins through the set of brake pads and you are now able to snap the anti rattle bracket in place. These helps hold the pads from sliding back and forth while in the caliper. With all those equipped, you may now slide in the rear brake pad pins, these will keep the caliper pins from sliding out. Using you favorite brake bleeding technique comes next, I usually work alone and find gravity bleeding to get the job done. One corner done! Now do this on the other side to finish one end of the car! Repeat the same steps on the other side and the front half of the car is completed!
With the front brakes finished you can head to the rear of the car. The rear of the car can go many different ways as was previously touched on, replacing the rear knuckles with 06-07 Wrx knuckles or rear knuckle adapters for your 04-08 Forester knuckles. When I picked up my brake calipers used they included the adapters and with that my mind was made up to try them out.
The adapters simply bolt to the standard caliper bracket mounting points and relocates the caliper. This is by far the easiest way to install the rear two piston calipers. Otherwise you will need to remove the rear knuckle by breaking it free of the CV axle, rear lateral links, strut and trailing arm. With an older higher mileage vehicle this could be quite a daunting task given that once rust takes hold of the lower lateral link bolt, drilling, cutting, destruction could be your only means of removing it. With that being said, we will follow along with the adapter kit install.
Starting with once again breaking the banjo bolt free before the caliper bolts will allow for easy removal. Up next are the caliper bracket bolts, with those removed the pulling the caliper off the brake rotor will finish the uninstallation process.
Removal of the rotors is the same as the fronts, using bolts in the rotor holes located near the lug studs. If you are tossing the rotors you can use your favorite hammer to dislodge the rotor from the hub. Without a rotor on the hub you can start your dust shield modifications. This is a necessary step to clear the larger rear rotors when you use the 04-08 Forester knuckles. There are a few ways to modify the dust shield, you can remove it completely or take a cut off wheel to take off about an inch to the outer edge of the shield. You can also remove the bearing, hub, and parking brake assembly to replace it with the Wrx version, plenty of work for very little improvement. Then place the rotor back on and check that everything clears, if not continue to cut away.
I wanted to try a different technique to leave more of the dust shield intact. I went about cutting notches in it a few inches apart to and then pulled the sections away from the rotor. If you have access to a welder you could even cut a few pieces of metal and cover these cuts to make it less of an eye sore.
Having completed your dust shield mods you can return to your brake adapters, these will install in the old caliper mounting holes. Brakes calipers can now be slid over the rotors and bolt them down, slipping in the brake pads. Now you can attach the caliper hardware to keep the pads in place and quiet. Double check all your fasteners and banjo bolts and begin your brake bleeding process. This completes the rear brakes and you can pump up the brake pedal to make sure it is at a proper height.
If you are still having issues with brake pedal height, stopping power or anything around these issues please take extreme care with your car and troubleshoot in an open area without people, vehicles, obstacles. If it is over your troubleshooting capabilities I'd recommend your favorite local auto shop. Personally, I had issues with my brake pedal after installation with a low inconsistent brake pedal while in the air. When I put the vehicle on the gorund the pedal was fine… my best guess is the factory hill assist was not happy with my jacks not being of equally set on the vehicle.
Lastly, if there are any break in procedures for your brake pads find an appropriate area and follow the manufacturers guidelines and steps.
Congrats! You have completed your “big brake” upgrade on your Forester! Now shine up the wheels and enjoy the view through the spokes of them staring back at you and your improved braking feel and performance!