1999 4Runner Rear 3-Link

Steadfast friend Justin wanted more travel and some welding practice, so we worked with him to design modifications to a common outboard shock relocation kit that was already on-hand and paired it with a simple 3-link design. 

The shock mount modifications raised the upper shock mount as high as possible without cutting into the cab.  This achieved approximately a 3"-4" higher shock position by using this boxed design.  This also allowed the lower shock mount to be moved from below the axle tube to the front of the axle tube and gave us the opportunity to utilize a custom lower shock mount.  We oriented  the lower bushing 90 degrees opposite to the upper mount to remove as much torque off of the shock shaft and seal head as possible during articulation. Many available configurations incorrectly orient this mount.  Given that the angle between shock shaft and axle is always greater during articulation than the angle between the frame and the shock body (and that these are rubber bushed shock ends rather than spherical bearing shock ends in this case) this is the logical way to orient these these bushings. It provides minimal stress to the seal head of the shock, and makes the rubber bushings last longer.  The angle change in this orientation was minimized due to our choice of using near parallel length upper and lower links. 

Perfect parallel links would keep bushings and pinion at constant angle during travel, but we opted to adjust the upper link to be slightly longer when setting static pinion angle at ride height.  The result is that during suspension droop, the pinion angle rolls slightly upwards, which helps maintain the pinion pointed at the output of the t-case and double-cardan joint. This minimizes u-joint angle and reduces stress on the drive-line.  A bonus feature is that all three link tubes are are identical, differing in length only by rod end adjustment.  Therefore, only one spare is needed to replace any of the three, which is of some concern for 1.5" tube links when it comes to rocks.

We did not optimize anti-squat geometry here as this is not a high-horse power vehicle and quite often operates in low-traction environments.  Therefore chassis squat during acceleration is not of concern.  The end result is that the suspension cycles 13.25" of travel despite using a 12" stroke shock.  The system articulates fully, one shock reaches full compression while the other reaches full extension. This means 12"+ of travel with maximal articulation.  

Contact us if you are interested in a similar set up for your vehicle!