Coil Spring Preload Adjustment (Shimming) Procedure

GENERAL INFORMATION
Front and rear shock absorbers used on the Viper can have either spring shims or reduced height spring seats installed on the shock absorber assemblies. The spring shims or reduced height spring seats are to be used only on vehicles that do not meet vehicle curb height specifications. Installation of spring shims or reduced height spring seats, is to be the only method used to correct vehicles not meeting front or rear curb height specification.

Installation of a spring shim will increase preload on the coil spring, thus raising the vehicles curb height. Installing a reduced height spring seat will have the opposite effect of decreasing coil spring preload, thus lowering vehicle curb height.

CAUTION: Do not attempt to stack up the spring shims. Only 1 spring shim can be installed per a shock absorber assembly. Also do not attempt to use both a reduced height spring seat and a spring shim to set vehicle to correct curb height.

If shock absorber/coil spring assemblies require shimming or installation of reduced height spring seats, to obtain correct vehicle curb height, use the following procedure.

PROCEDURE
1. Remove both front or rear shock absorber/coil spring assemblies from the vehicle.

CAUTION: Do not clamp the shock absorber in a vise not equipped with protective caps on the jaws of the vise. Failure to use protective caps will result in damage to bushing and clevis of shock absorber.








2. Securely hold the shock absorber in a vise. The front shock absorber can be held in the vise by clamping the lower bushing of the shock absorber. The rear shock absorber can be held in the vise by clamping the shock absorber clevis in the jaws of the vise.





3. Compress shock absorber coil spring using Professional Services Equipment Spring Compressor GP-2020-C3.5 or an equivalent.The spring compressor is to be equipped with an A-20 spring shoe on the top and bottom.





4. Compress the coil spring enough to allow the coil spring upper retainer to be removed from coil spring and shock absorber.





5. At this time, if the vehicle was lower then curb height specification add a maximum of 1 spring shim under the upper spring seat. If vehicle was higher then curb height specification, remove original upper spring seat and replace it with the reduced height spring seat shown.





6. When installing spring shim and upper spring seat, be sure end of coil spring is not positioned at notch in spring shim or upper spring seat.
7. Un-compress the coil spring until the top coil of the spring is about to contact the upper seat for the coil spring. At this point, again check that the end of the last coil is not positioned in the gap of the spring shim or the coil spring upper seat.
8. Fully un-compress the coil spring and remove the spring compressor from the coil spring.
9. Remove the shock absorber from the vise.
10. After servicing shock absorber assemblies, install both front or rear shock absorber/coil spring assemblies back on vehicle. When installing shock absorber assemblies, vehicle must be at design height before tightening and torquing shock absorber assembly mounting bolts.