QA1 Rear Double-Adjustable Coilover Kit for 1979-2004 Ford Mustang

Move rear ride height and damping adjustments onto one matched system

QA1 RCK52406 converts the rear of a supported solid-axle 1979-2004 Mustang to a bolt-in coilover arrangement. Double-adjustable aluminum shocks, 130 lb/in springs, mounting brackets, and hardware provide independent compression, rebound, and ride-height control while retaining a serviceable package.

Key Features

• RCK52406 is a complete bolt-in rear coilover conversion for solid-axle Mustangs
• Double-adjustable aluminum shocks provide independent compression and rebound tuning
• 130 lb/in coil springs are included
• Threaded shock bodies allow up to approximately two inches of lowering
• Application-specific upper and lower mounting brackets are included
• Best-in-class lifetime shock warranty is available under current QA1 registration terms

Fitment

Specifications

What's Included

• One matched pair of QA1 RCK52406 rear double-adjustable coilover shocks
• Two 130 lb/in coil springs, application-specific mounting brackets, and required kit hardware
• Rear axle, control arms, wheels, tires, exhaust parts, brake components, and alignment service are not included

About QA1

QA1 develops rebuildable, tunable suspension systems for street, drag, and handling applications. Its Mustang rear coilover package combines application-specific brackets, spring rate, shock travel, and independent damping adjustment in one bolt-in system.

Related Parts

• No internal companion part is linked because control arms, axle hardware, exhaust routing, wheels, and tires must match the exact solid-axle Mustang and intended use.

FAQ

It is a bolt-in rear double-adjustable coilover conversion kit for the supported solid-axle 1979-2004 Ford Mustang.

No. QA1 specifically excludes Cobra IRS applications from this exact kit.

The verified package includes 130 lb/in rear coil springs.

Yes. The double-adjustable shocks provide independent compression and rebound tuning.

The threaded shock bodies allow up to approximately two inches of lowering from stock, subject to safe travel and clearance.

Yes. The exact package includes the application-specific brackets and related installation hardware.

No. Exhaust, brake-line, wheel, tire, axle, and body clearances must be checked on the exact car through full suspension travel.

QA1 advertises lifetime shock coverage after registration, subject to its current warranty terms and exclusions.

Installation Instructions

1. Verify the Mustang has a solid rear axle and inventory every RCK52406 component before removing the original rear suspension parts.
2. Measure baseline ride height, support the chassis and axle safely, and follow the current QA1 removal sequence.
3. Install the upper and lower coilover brackets in the documented orientation and torque hardware only at the specified suspension position.
4. Assemble and install the matched springs and shocks, then set equal preliminary ride height and damping on both sides.
5. Cycle the suspension and inspect axle, exhaust, brake-line, wheel, tire, spring, shock, and body clearance before driving.
6. Road-test cautiously, remeasure ride height, and recheck torque and clearances after the initial service interval.

California Proposition 65 Warning: This product can expose you to chemicals including antimony oxide and other chemicals known to the State of California to cause cancer or reproductive harm. For more information, visit www.P65Warnings.ca.gov.