2015 WRX & STI Rear Control Arms Installation

As most of you already know, control arms serve a very important function to a cars handling and suspension. Essentially, they connect the steering of your vehicle to the chassis. Control arms permit the wheels to move and control the motion of the wheels through pivoting. Without control arms, your tires would not have any control when hitting bumbs. There would be nothing to aid the wheels from ascending and descending. The tires would be fixed and cause for an unbearably rough ride.

With the 2015 WRX/STI in full production, Subaru fans are getting a taste of the new stiffer and more refined chassis. ISC offers a full product line for the 2015 chassis including wheel spacers coilovers and rear control arms. The chassis can be best described as more rigid. Combine this chassis with the improved throttle response and upgraded control arms, and the 2015 WRX/STI is a well tuned machine that clearly outdoes it’s predecessor. From the manufacturer, the chassis has been tuned to be 14% stiffer while the suspension is 21% stiffer than previous models.

ISC rear control arms are some of the best in the industry because of the use of stainless steel hardware and a cnc’d 6061 aluminum arm. Many competitors use welded or stamped steel which is much weaker and less reliable. ISC control arms are lighter, stiffer, and stronger than the competition. These rear control arms offer over 5 degrees of camber adjustability and use a pillow ball rod end with a street seal protective cover to protect the bearing from harsh elements like sand and road salt. At a price point of 475.00 to 575.00 these rear control arms are hard to beat, and backed by ISC’S industry leading warranty. Combine ISC’s rear control arms with Subaru’s refined chassis and you will have an ultimate machine that will offer a smooth ride and rip through corners.

ISC control arms are not only offered for the 2015 WRX/STI but many other models aswell. View the following list for fitment of all models:

  • 2010+ legacy GT
  • 2008-2014 WRX
  • 2008-2014 STI
  • 2013+ BRZ and FRS
  • 2015+ WRX
  • 2015+ STI

You can find all of ISC’s rear control arms for the models listed above at AJW Performance Products:

2010+ Legacy GT Rear Control Arms

2008+ WRX Rear Control Arms

2008+ STI Rear Control Arms

2013+ BRZ & FRS Rear Control Arms

ISC Rear Control Arm Installation


  1. If possible, spray all the bolts being removed ( lower shock bolt, sway bar end link bolts, and inner and outer control arm bolts) a few times for few days before the installation.
  2. Remove the lower shock bolts, along with the sway bar end link bolts.
  3. Remove the inner and outer control arm bolts. These are very tight so a large breaker bar with impact sockets will work best. (I had a 3 foot breaker bar on it and also had to use a torch to heat up the nut to remove mine).
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  5. Now that the OEM control arm is out of the car. You can begin to setup the ISC control arm. To establish a starting point, I un-threaded the Heim joint all the way from the arm itself and from the extension nut. Apply anti-seize to all threads. Then I simultaneously started to thread the Heim joint and the extension nut into the end of the arm, so that there was equal adjustment on both sides of the nut. Since one side of the nut is a left handed thread and one side is a right handed thread, all you have to do is hang the arm off the end of a table, hold the Heim joint still and spin the extension nut all the way till it bottoms out. I then adjusted the ISC arm to the same length as the stock OEM control arm. Tighten down both locknuts to assure the length of the arm does not change.
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  7. Pack the Heim joint with lots of grease. I also found some rod end dust seals online and decided they would be a good addition to keep the joint free of road debris.
  8. Install ISC control arm into back into the car. New hardware is supplied for the sway bar and the lower shock mount, but the original hardware is re used for the inner mount. Be sure everything is tight/properly torqued.
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  10. Repeat steps for the other side of car.
  11. Since the length of the control arm was only eye-balled, the alignment of the car could be way off, or it could be close. GO GET AN ALIGNMENT ASAP!!
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