Installation Notes:
Replacing the rear coil springs on a 4runner is relatively easy. The short step by step is:
Lift the back end of the truck and support the frame on jack stands
Remove rear tires
Note that you may need to remove the tires then lower the frame onto jack stands if the stands are too short to reach w/ the tires on.
Disconnect sway bar and shocks from axle
You may also need to disconnect the panhard bar if you can't get enough down travel to fit the spacers in place.
Press down on the now free-hanging axle and swap the springs
You can remove the stock rubber spring isolator as the coil spacers serve the same purpose.
Note on some aftermarket springs, the top of the coil may not have a flattened/tapered end like the stock coils do and thus may not sit flat against the spacer. If this is the case, you can use an angle grinder to slightly flatten the projecting end of the spring to fit better. The spacers themselves are a compliant poly urethane material and will accommodate some unevenness on the top end of the spring.
If you are going from stock height springs to any lift, you may need to replace the rear axle brake line with a longer one
Reinstall the disconnected parts to complete the installation.
If you had to remove the panhard bar and need to re-install it, you may need to add some weight to the passenger side (have a few friends stand on that side of the tailgate) or use a bottle or floor jack under the passenger side of the axle to lift it a little to allow the panhard mounting bolts to be reattached.
If you find the two ends of the panhard bar are more than a few inches different in height, you may need a panhard drop bracket...
Check all fasteners in 100-200 miles to make sure they have not loosened
If you hear a clunking noise under braking/accelerating, you may want to double check your factory bottle jack, especially if it was used in the installation. It may not have been replaced tight enough and is making that noise.
The rear brake Load Sensing Proportioning Valve (LSPV) sensing arm should be adjusted to compensate for the lift achieved.
The sensing rod bolts to the axle and uses ride height to adjust rear brake pressure.
If the LSPV adjusting bracket was purchased with the spacers, un-bolt the sensing rod from the axle, bolt in the LSPV adjusting bracket with the stock bolts.
Then bolt the sensing rod to the top of the bracket with the supplied bolts.
Check for proper brake operation and fine tune the sensing rod as needed:
Movement of the sensing rod upward at the LSPV = more rear braking, lowering it = less rear braking.
By jamming a piece of wood (2x4 or similar) between the brake drum and the wheel well, the axle should be low enough to work on the springs. The only tricky part of this, if using the spacers with lift springs is getting the springs compressed a couple of inches, as the spring compressors are difficult to work with in this confined area.
Here is a write-up on the installation process with additional photos and tips:
All Pro Off-Road Coil Spring Spacer Review- ORN
With variations in rear suspensions, you might find that the rear springs might pull away from the coil spacer under full spring droop. If this happens there are several options available. One option is to install some limiting straps on the rear axle to keep it from dropping low enough to take the tension off the springs. Straps are available from many off-road parts shops. Another option is to install some small u-bolt clamps to attach the spring to the spacer. This will involve drilling a small (~1/4") hole into the edge of the spacer to slide the u-bolt in place. Typically, you'll need 2-3 u-bolts per spring to hold it in place. U-bolts should be available from most hardware stores. If you can't find any locally, a set of 4-6 can be supplied for a cost of $20.00 - $25.00 plus shipping. Contact 4Crawler Offroad for more information. For this option, provide a measurement of the diameter of the coil spring steel and whether you want 2 or 3 u-bolts per side.
