Maximum Motorsports Extreme-Duty Adjustable Rear lower Control Arms, 1983-1989 Thunderbird MMRLCA-40

Maximum Motorsports
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Extreme-Duty Rear Lower Control Arms with adjustable-height spring perch and spherical bearings. Fits 1983-1988 Thunderbird with Mustang rear springs.

Improves traction and handling by reducing the unwanted deflection allowed by the stock soft rubber bushings and flexible stamped steel control arm.

Rated for Big Power!
These MM Extreme-Duty control arms are robust enough for hard launches at the strip by a Thunderbird with 1,000 rwhp, on slicks.

Use with Mustang springs!
The adjustable-height feature of these control arms was designed for aftermarket springs intended for 1979-2004 solid-axle equipped Mustangs.

Why use Mustang springs?
Aftermarket lowering and performance springs are no longer made for 1983-1988 Thunderbirds. These MM control arms allow readily available aftermarket Mustang rear springs to be fitted to your Thunderbird. That gives you several choices of springs, as you can use any rear spring listed for a solid-axle equipped 1979-2004 Mustang. Order a pair of Mustang rear springs.

NOT for use with Thunderbird springs
If Thunderbird springs, either stock or aftermarket, are installed with these control arms the rear ride height will be raised, compared to a stock Thunderbird control arm, even when the adjuster is at its lowest setting.

Better by design

  • Stress on the chassis torque-boxes is greatly reduced because the MM bushing design allows proper articulation of the rear suspension.
  • Spherical bearing at the axle end allows articulation while eliminating deflection.
  • Large 2" diameter round steel tube design for highest strength.

Why do I need these MM Rear Lower Control Arms?

  • You can install aftermarket lowering and performance springs. Thunderbird springs are no longer available; these control arms allow you to install readily available Mustang springs.
  • Adjustable ride height lets you change your Mustang's instant center location to tune the anti-squat percentage for optimum traction.
  • The stock Thunderbird rear lower control arms are fitted with very large, soft rubber bushings. Those bushings allow the axle to shift fore and aft, causing the toe of the rear tires to change. Toe changes cause instability as the rear of the car steers itself in unpredictable directions.
  • Deflection of the rubber bushings allows axle wind-up during acceleration, which in turn causes wheel hop.
  • MM Rear Lower Control Arms were designed by our engineering team to eliminate fore/aft movement of the axle, while also retaining the suspension's ability to properly articulate. This improves performance without unnecessarily compromising handling or ride quality.
  • Potential of torque-box damage is greatly reduced because the MM design with spherical bearings allows the suspension to articulate easily.
  • Manufactured by MM in the USA.

Fits 1983-1988 Thunderbird. Includes adjustable-height spring perch and a swaybar mount for a stock-style rear swaybar.


  • Pair of assembled rear lower control arms
  • Urethane end cap shields for spherical bearings
  • Mounting bolts and nuts
  • Grease for the urethane end cap shields
  • Installation instructions


  • Large spherical bearing at both ends of each control arm completely eliminates unwanted deflection, while allowing proper articulation of the suspension.
  • Plated steel reducer inserts in the spherical bearings
  • Strong and stiff round steel tube construction
  • Adjustable-height spring perch
  • Durable black powdercoated finish
  • Hard-anodized aluminum jack-bolt
  • Grease fitting to easily lubricate jack-bolt threads
  • Designed and manufactured by MM in the USA.