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How to Install QA1 Double Adjustable Rear Shock on your Mustang

Installation Time

2 hours

Tools Required
  • Floor Jack
  • Jack Stands
  • Wrenches (SAE and/or Metric)
  • Socket Set (SAE and/or Metric)
  • Snap Ring Pliers
  • Spanner Wrench Set (QA1 P/N T114W or T115W)
  • Permatex® Anti-Seize Lubricant
American Muscle
Shop Parts in this Guide

Coil-Over Shock Assembly


1. Thread the aluminum lock nut (shoulder up) and the spring seat adjuster nut (shoulder up) down to the last thread - NO FURTHER. Now is a good time to lubricate the threads of the shock with Permatex® Anti-Seize lubricant.


2. QA1 highly recommends using Thrust Bearing Kit (QA1 P/N 7888-109) for ease of adjustment. If the thrust bearing kit is used, coat both sides of the washers with Permatex® Anti-Seize lubricant. Install the stainless steel
spring seat washer, followed by the bearing and finally, the second washer.


3. If the thrust bearing kit is not used, coat one side of the stainless steel spring seat washer with Permatex® Anti-Seize lubricant. Place the lubricated side of the washer down on the spring seat.


4. With the piston rod fully extended, slide the spring over the shock down to the spring seat adjuster and install the spring cap. Note: xx401 and xx402 shock require 10” springs to be compressed about ½” for installation.


5. Make all ride height changes with the car off the ground and the suspension unloaded. Apply Permatex® Anti-Seize lubricant before making any adjustments to the ride height. Once you have the ride height set, tighten the lock nut against the spring seat adjuster using spanner wrench part number T114W or T115W.


Note: A four wheel alignment should be performed by a qualified alignment shop after any changes to the suspension system.



*M - Proper measurement of shock lengths, extended, compressed and shock ride height are taken from the center of the top shock mount to the center of the bottom shock mount.


• For proper measurement of other style shock mountings see diagram below.


Compressed and extended lengths
measured from the center of loop(s)
and/or shaft shoulder and/or stud
shoulder.


If measuring from mounting surface
to mounting surface, deduct 5/8“ for
each mounting surface to allow for
the bushings.


Note: RS shocks cannot be used as coil-over shocks


Shock Valving Adjustments


QA1 shocks have 18 damping settings per knob. There are 6 clicks per revolution of each knob, and each knob has 3 complete revolutions. The knob set fully counter clockwise is the softest setting - start your adjustments from that point.


Recommended base settings to begin testing with are as follows:


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