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How to Replace a Factory Exhaust Flex Pipe

by Joshua Smyth

Flex pipes are flexible pieces of piping that fulfill an important role in a car's exhaust system by absorbing the vibration and movement of the car's transmission and engine. They also compensate for movement and flexing in the body of the car. By doing so, they absorb stress that might otherwise cause cracks, leaks and other damage. They also provide a breaking point if the muffler gets caught on something as you drive. With all this stress to absorb, the flex pipe that came with your car from the factory often needs replacement, but it's an easy job to do.

Get under the car. If your vehicle is raised high enough for you to fit underneath it on your back, you can slide under it. Otherwise, you will need to raise your car up, either by placing it on an automobile lift in a garage or by raising the back end of the car on hand-pumped jacks. If you jack up the car, check very carefully that the jacks are secure before getting under the raised end.

Find the flex pipe. Consult your owner's manual to find it or just look under the car with a flashlight. It is a flexible pipe that has one end connected to the muffler with a flange and the other end joined to the exhaust pipe with a pipe elbow.

Grab the bolts holding the flex pipe to the flange on the muffler with a wrench. Turn counterclockwise to remove them. Then pull the flex pipe out of the flange.

Remove the clamp holding the flex pipe to the exhaust downpipe with the wrench. This will release the old flex pipe, which you can now set aside.

Pull out the old gasket that sat between the flex pipe and the muffler flange. This will allow you to clean out the flange with a stiff wire brush.

Hammer out any dents from the end of the exhaust downpipe. This will let the new flex pipe seal tightly to it.

Loosen the nuts holding the muffler and downpipe. You may need to move both of them slowly to fit in the new flex pipe.

Coat a new muffler gasket with exhaust sealer, then place it in the muffler flange and fit the end of the new flex pipe over it. You must use the end of the flex pipe that has a hard elbow with holes for bolts.

Coat the end of the downpipe with more exhaust sealant and place the free end of the new flex pipe over it. Adjust the position of the muffler and downpipe until the flex pipe is straight but free of tension.

Thread bolts through the holes in the end of the flex pipe attached to the muffler flange. Tighten them with a wrench to secure the pipe to the flange.

Place a new clamp around the flex pipe where it meets the downpipe and tighten it with a wrench. This will secure the flex pipe in place.

Retighten the bolts holding the muffler and downpipe and cut any plastic ties that are wrapped around the flex pipe.

Items you will need

About the Author

Joshua Smyth started writing in 2003 and is based in St. John's, Newfoundland. He has written for the award-winning "Cord Weekly" and for "Blueprint Magazine" in Waterloo, Ontario, where he spent a year as editor-in-chief. He holds a Bachelor of Arts in political science and economics from Wilfrid Laurier University.

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Photo Credits

  • exhaust pipe image by A74.FR Ben Fontaine from Fotolia.com