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Exhaust Hanger Replacement

New exhaust-pipe straps eliminate rattles and bangs

Most General Motors musclecar exhaust systems are secured to the underside of the vehicle with exhaust hangers. These metal brackets are attached to pieces of rubber, which flex and allow the pipe to move. Like all rubber items, smog, heat, cold, salt and constant movement wear these parts at an alarming rate. With GM's "over the rear axle" exhaust-tubing design, a loose exhaust pipe can contact several undercarriage spots, resulting in an annoying rattle or occasional bang (as experienced after driving over a serious pothole).

As the rubber section of these exhaust-pipe hangers wears, it becomes increasingly loose and flexible, which allows more and more movement of the pipe. Eventually, rattling can be experienced even while driving on a relatively smooth road. The fix is simple and the parts, as shown above, are available at most auto-parts retailers or muffler shops.

Dual Exhaust

Most dual-exhaust vehicles have two hangers per side. The first is at the front or rear of the muffler, where the pipe enters or exits, and the second is shown here at the rear. Removing and replacing either is simply a matter of reversing the removal process. Make sure you have the correct replacement hangers or your system will be out of alignment, which often results in the rattling problem you're trying to fix. The small rear hanger usually goes away first because of the basic design of the item—attached to the outside of the framerail, usually next to the fuel tank.

Clamping Down

Typically, a U-clamp is used to attach the pipe itself to the hanger. Before buying a set of replacement clamps, measure the outside diameter of your exhaust pipe—these clamps come in several sizes to fit over the tube. Too big or too small will not work. These clamps are usually attached with 1/2-inch nuts and a lower retainer as shown in the photo. If your clamps are rusty, an overnight soaking with a penetrating lubricant will help in removing the nuts. We are doing this remove-and-replace project on a vehicle lift, but it can be easily accomplished on the garage floor.

Hanging Around

The hanger is attached to the framerail with a single 9/16-inch bolt that can be removed with an open-end wrench or ratchet and socket. The hangers look basically the same, but upon closer inspection of the mounting bracket, where the hanger attaches to the pipe, they're reversed from side to side. Replace the hanger with its exact duplicate for that side. We are replacing the U-clamps but re-using the factory attaching bolt for the hanger. A quick cleanup on a wire wheel will remove any rust or dirt, and it doesn't hurt to run a thread tap into the frame if you live in a rust-belt area.

New U

Here's the replacement hanger in position with the new U-clamp securing the pipe. It's a good idea to whack the pipe with your hand a few times before completely tightening the clamp to make sure the position is correct. If not, you'll hear the pipe contacting the frame and have to readjust the pipe to clear whatever it's hitting. Compare the position of the U-clamp in the first photo and the final photo. Notice the U-clamp is turned up toward the inner fender. This is done for two reasons: It prevents road debris (paper, plastic bags, etc.) from catching on the bottom of the U-clamp ends and is obscured when looking at the profile of the vehicle. Just an artistic touch, but it works well.