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1999-2004 Mustang IRS Torque Specifications

Created by Jay Walling
Last Updated 1/6/2022

Upgrading the rear suspension on IRS-equipped 99-04 Cobras is common in high horsepower applications. Knowing the proper torque is key with any upgrade!

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In 1999, Ford introduced the updated New Edge Mustang. This redesigned Mustang featured sharper body styling, upgraded engine platforms, and a new independent Rear Suspension for the SVT Cobra chassis. This IRS rear end was extremely popular with street and open-track enthusiasts who wanted to carve corners. But when it came to any high horsepower drag racing applications, this design lacked in some areas.

1999-2004 Mustang IRS Torque Specifications - 1999-2004 Mustang IRS Torque Specifications

Over the years, aftermarket manufacturers have produced upgraded components for the IRS rear end that have completely redesigned the downfalls plaguing the 99-04 IRS. As with any performance modification, proper torque specs are needed to ensure your upgrades are installed the way they should be!


1999-2004 IRS Torque Guide

Suspension Component Newton Meters"NM" Pound-Feet "LB/FT"
Subframe-to-Body Bolts 103 76
Subframe-to-Rear Bracket Bolts 103 76
Subframe Rear Bracket-to-Body Bolts 80 59
Shock Absorber-to-Lower Arm and Bushing Bolts 133 98
Shock Absorber-to-Body Nuts 40 30
Upper Arm and Bushing-to-Subframe Nuts 90 66
Upper Arm and Bushing-to-Knuckle Nuts 90 66
Lower Arm and Bushing-to-Subframe Bolts 250 184
Lower Arm and Bushing-to-Knuckle Nuts 115 85
Toe Link-to-Subframe Nuts 48 35
Toe Link-to-Knuckle Nuts 48 35
Stabilizer Bar Bracket Bolts 55 41
Stabilizer Bar Link Nuts 48 35
Rear Axle Differential Rear Insulator-to-Axle Housing Bolts 103 76
Rear Brake Disc Dust Shield-to-Knuckle Bolts 10 n/a
Brake Line-to-Rear Brake Caliper Bolts 40 30
Parking Brake Cable to Lower Arm Bolts 15 11
ABS Sensor Bolts 23 17
Axle Shaft-to-Hub Retainer 325 240
Wheel Lug Nuts 129 95


Source:Alldata.com