HOW TO INSTALL A FLOWMASTER PRO SERIES AXLE-BACK FOR YOUR 2005-2010 MUSTANG GT AND GT500

Pick a side to start with. Loosen the nut on the clamp that connects the mufflers to the over-axle pipe with a 15mm socket (no need to remove it). 

Each muffler has two hangers supported by two bolts each. Use a 13mm socket to remove them on the rear most hanger first. 

Now do the last hanger on that side. As the bolts become loose, try to support the muffler just to be safe. 

Now slide the muffler off the over-axle pipe. 

With a 15mm socket, remove the nut from the clamps supplied in the kit and slip a little grease on the threads for anti-seize purposes. Slide these onto the Flowmaster mufflers. 

Slip on the muffler hangers to the Flowmasters (the left side for the left muffler and right side for the right muffler). 

Pick a side. Take the muffler for that side, and slide it on the over-axle pipe until the knob on the pipe is inside the cutout on the muffler pipe. While supporting it, tighten the clamp a bit and keep the support for safety’s sake. 

With the 13mm, install the rear hanger since it is easier. You may remove the muffler support 

Install the second hanger with the 13mm socket. NOTE: the bolt above the muffler will be hard to reach, so using a 13mm ratcheting box-end or adjustable wrench will make it much easier. 

Then tighten the muffler clamp all the way once the hangers are in place. 

If one of the mufflers does not sit centered in the bumper cutout, it is because of the H-pipe. Loosen the 2 H-pipe clamps and the muffler clamp, and then adjust it to your liking. 

Installation Instructions Written By AmericanMuscle Customer Carmine Lomonaco 6.25.2013