Yesterday I installed a set of Whiteline subframe inserts (KDT918). Thanks to Freon and others who posted instructions, photos, and torque values… I found them to be very helpful. I am extremely pleased with the results. Only one test drive so far, but initial impressions are that the rear wheels now feel much more planted and secure.
I thought I’d pass along a couple comments on the installation process:
As shown in the photo, I found that the bolts attaching the diagonal subframe brace to the chassis on my car are 16mm Torx bolts, not hex bolts as others have mentioned. Good thing I had a complete set of Torx sockets!
The position of the subframe and load on the various hardware can be controlled by either lifting or lowering the rear differential with your floor jack. Unless you adjust the jack to either compress or relax the rear suspension for the specific task you are trying to accomplish, you’ll be working against yourself. Here are the steps I recommend:
- With the suspension compressed, remove the rear subframe bushing bolts and loosen the front subframe bushing bolts. Remove the 16mm bolts securing the diagonal subframe braces. Note: the right diagonal brace on my car was loaded outboard and aft by the cross brace that runs inboard and forward to the center of the car. I chose to leave the forward bolt installed a few threads to prevent the diagonal brace from finding a new location and making it difficult to restart the bolts.
- With the suspension relaxed, insert the upper and lower rear subframe bushing inserts.
- With the suspension compressed, loosely reinstall the rear subframe bushing bolts, then remove the front subframe bushing bolts.
- With the suspension relaxed, install the upper front subframe bushing insert.
- With the suspension compressed, install the lower front subframe bushing insert.
- Loosely reinstall the front subframe bushing bolts and diagonal cross brace bolts.
- Snug down all the loosened bolts first, then tighten and torque. I used 74 lb ft on the subframe bolts, and 'good’n tight' on the cross brace bolts.
Here are photos of the bushings before install, before and after photos of the front and rear bushings, and a photo of the 16mm Torx bolts securing the diagonal cross braces. In the last photo (without the inserts installed), you can imaging that with the front subframe bushing lower inserts installed, the diagonal cross brace is displaced by the thickness of the insert (approximately 3/8”). I’m sure that tightening the cross brace bolts results in a fair amount of stress on the cross brace. Ideally a spacer would be fabricated to take up some of this space and reduce the amount of compression/bending load on the brace. I left it as is and tightened the bolts.