14mm bolt kit fits IRS subframe and RLCA mounting, 1999-2004

In stock
Regular price $19.97
Designed for Vehicles / Universal (no vehicles listed)

While these 14mm bolts are considered a requirementfor the IRS, they have 2 applications:

  • Cobra IRS: attaches the 2 forward IRS subframe mounts to the chassis. 1 kit required per car.
  • Solid axle: attaches 1999-2004 rear lower control arms to a 1999-2004 Mustang chassis and to a 1999-2004 rear axle housing. Two kits required per car.

Why does the Cobra IRS need these?
The 2 forward mounting points on the 1999-2004 IRS-equipped Cobras have 14mm holes in both the chassis and the steel crush sleeve of the OEM rubber bushings. But on the assembly line, Ford used 12mm bolts to secure the IRS subframe to the chassis to speed up installation. Problem is, putting 12mm bolts in 14mm holes allows the subframe to shift relative to the chassis. That can cause noise and even changes the rear wheel alignment.

This kit replaces those 12mm bolts with better-fitting 14mm bolts. No more subframe shifting, no more noise, no more unpredictable rear alignment changes.

MM sources this hardware from Ford. Nothing beats the OEM hardware for functional, correct-fitting design and excellent anti-corrosion coating.


  • 1 kit required for 1 IRS-equipped 1999-04 Mustang, for the forward subframe-to-chassis attachment.
  • For the rearward IRS-to-chassis attachment, use the MMF-1 hardware kit.
  • 2 kits required for 1 solid axle-equipped 1999-04 Mustang, to secure each end of both rear lower control arms.
  • Not for 1979-98 chassis. Use MMF-5 for those 12mm applications.