4WD FRONT SUSPENSION RIDE HEIGHT FACTORY ADJUSTMENT
Below is the method for setting ride height back to the maximum allowable height specified by Nissan.
Tools required:
Socket set
Spanner set
Ruler/tape measure
Level concrete surface
Jack & jackstands OR hoist
This is a one man job.
Last time I adjusted mine I was lucky enough to borrow a hoist:
Firstly you need a reference reading. Drive the vehicle onto the level concrete surface. Using the ruler, take two measurements as described in the image below, one between the ground and the bottom of the front steering stop bracket, and one between the ground and the centre of the lower link spindle. Subtract the larger from the smaller. This is your 'H' value. Repeat for the other side of the vehicle.
The allowable range for 'H' is 41-51mm. Your aim is 51mm on both sides for max factory ride height.
If one or both of your 'H's is less than 51mm, you need to increase the preload on the torsion springs. Chock the rear wheels, jack the front of the vehicle up on the diff crossmember so that the wheels are off the ground, and install jackstands, lower the jack. Don't get under a vehicle supported only by a jack.
Using a spanner and a socket with a ratchet arm, tighten the preload adjustment bolts at the back of the torsion bars. If one side of your car is lower than the other, tighten it proportionally more. Tighten maybe five full rotations, then it's time to take another measurement.
Lower the vehicle off the jackstands, and bounce the front by hand, then roll it forward 1-2m, then back 1-2m to settle the suspension. Take another pair of measurements as detailed below. Repeat the jack, preload, settle, measure process until you acheive the desired 'H' on both sides (~51mm if you want maximum ride height).
An alignment is probably advisable if your original H was way off your new H - I adjusted mine without an alignment and have found that my tyres wear unevenly.
A few notes:
- If you run out of preload adjustment, it's time to re-index your torsion springs. This is not covered in this guide as I have never needed to do it. This would only be required if your torsion springs have been mistreated, or if your vehicle has been lowered previously.
- This guide does not detail obtaining a 'lift' by adjustment of torsion spring preload. A "lift" involves exceeding 'H' by an unknown figure for a total of 2" of ride height increase. Note that any change in 'H' results in a greater change in actual ride height - H is just the vertical component of the triangle formed by the lower link arm.