Results 1 to 8 of 8
  1. #1

    Default Differential question

    Will a 99 complete rear end bolt up to an 85 RS. I have read plenty of articles here, and most are what bits and pieces to use.


  2. #2


    From what I recall, they will not. The '99-04 rears are something like 1.5" wider per side (3" overall) than the fox rears. I also read that the control arm bolt size changed from the previous years.

    If you're looking for a 5-lug disc rear, look for a '94-98.

    1985 Mustang GT - Build Thread
    347 (10.5CR, AFR 185's, PP Crosswind, Comp Custom Cam, Holley SA "670"), T-5, 8.8 w/3.55's, MM SFC's, T/A, PHB, LCA's, STB, KMB, Bilsteins, MM/H&R Springs, SN95 5-Lug, Cobra Brakes, '04 Mach 1 Steering Rack

  3. #3


    In addition, the RLCA bolt hole are 14mm instead of 12mm and the brake hose routing is different.
    Jack Hidley
    Maximum Motorsports Tech Support

  4. #4


    I know the axles are longer but the housings are the same. I was foing to put my 4 lug into it, and keep the brakes until I can get everything for a 5 lug. Its hard to not get it for $100.00

  5. #5


    I was thinking i can attach the main brake line directly to the set up in the 99.
    Last edited by Messe; 11-09-2018 at 03:22 PM.

  6. #6


    The housings are not the same width.

    The 1979-98 7.5" and 8.8" housings are all the same width. The 1999-2004 8.8" housings are 1.5" wider.

    In addition to this, in 1994, each axle got 0.75" wider. In 1999, each axle got an additional 0.75" wider. It is impossible to install the 1999-2004 axles into a pre 1999 housing.
    Jack Hidley
    Maximum Motorsports Tech Support

  7. #7


    the one for sale is a 7.5 out of a 99 V6 I was going to swap my 85 axles into it, so i can maintain my 4 lug for now.

  8. #8


    Oh well, i will skip this.
    Thanks all for the input

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts