Subaru WRX STi
Cusco Rear Subframe Brace
The Supplies you'll need for this installation are:
1. Cusco Rear Subframe Brace
The tools you'll need for this installation are:
Torque Wrench (25 - 250 ft lb range recommended)
2. Ratchet or breaker bar
3. 19mm Socket & a 3 to 6 inch extension
5. Jack Stand
6. Wheel Chocks
Once again, Cusco steps to the plate with instructions only in Kanji.
For easier reference, the above photos have been colorized. In photo 1, the 2 large yellow arrows show where the 2 subframe bolts are. Photos 2 and 3 show the right and left ends of the brace after installation.
The following two photos are of our installation. The yellow arrow in the Cusco photo 2 and our photo 1 point to the rear anti-sway bar to help you get a better idea of the area in which we'll be working.
1. Prepping the car
Park on a flat, level work area. Chock the front wheels to keep the car from shifting. Using standard jack locations, jack the rear of the car up high enough to clear your jack stand. Line your jack stand up under your subframe and lower the car down enough so that the jack stand is ready to hold up the subframe if needed. DO NOT SUPPORT THE WEIGHT OF THE CAR ON THE SUBFRAME. All we want to do is prevent the subframe from dropping out of place while working on the brace installation.
2. Remove the subframe's 2 primary bolts.
We're interested in Step 12 in the shop manual reference (below). The rear of the car is toward the top of the diagram with the front of the car toward the bottom. DO NOT REMOVE ANY OF THE OTHER ITEMS REFERENCED ON THIS PAGE.
A. Using the ratchet or breaker bar, loosen the 2 bolts referenced in step 12 (above) while watching to ensure that the subframe doesn't drop. Raise the jack stand, as needed, to support the subframe in place.
B. DO NOT USE YOUR TORQUE WRENCH TO LOOSEN FASTENERS. It will ruin your wrench.
3. Once you're sure the subframe is stable, slide the brace into place. Remove 1 bolt, start the bolt for that side of the brace, then remove the other bolt and feed it through the other side of the brace. Once both sides of the brace are in place, tighten the bolts to finger tight.
4. Alternating between each side of the brace, work your way toward the target torque of both bolts: 145 Nm (106.9 Ft-Lb); Bolts T9 in the next diagram.
A. Torque wrenches are always more accurate in the middle of their ranges than they are at the edges of their capacity. A wrench with a range of 25-250 ft-lb would work for this application.
B. Because of the extreme torque being placed on these bolts, it is wise to have someone nearby to help (and keep an eye on the car). You don't want the car to shift and fall off the jack/jack stands. Having it happen without nearby help could be life threatening.
C. Fasteners exposed to extreme torques often need to be replaced instead of re-used. Check with your Subaru dealer for the proper factory replacement bolts.
5. Remove the jack stands, lower the car, and double check your work. Once you're sure that the whole rear end of your car hasn't fallen to the ground, it's time for a very gentle, short test drive. After the test drive, do another visual inspection. Doing a double check might not be a bad idea either. Setting your torque wrench for 100 ft lb will help check for anything that's gotten too loose without over-torquing the bolts.
If any of the above steps give you second thoughts, then you can always take your subframe brace to your dealership and ask them to install it for you. They have lifts, the right tools, and 3 large guys named Guido to help them get the final torque muscled down on those 2 bolts. Also, their work will be warrantied. Total shop time is under 30 minutes which, locally, is about $45. DAMHIK IJK OK.
(C) 1995 - Present, Mark Johnson. All rights reserved.