Tuesday, November 5, 2013

How Do I Change My Muffler

Replacing a muffler can be a rewarding job that is quickly completed with a few tools---or it can be the task from Hades. A simple look at the muffler will help you determine which way the job will likely go and help make the decision about doing it yourself easier. If its held on with bolted flanges, it should go well. Replacing a muffler held on with U clamps might require special tools and be a job better left to experts.

Taking Off a Flanged Muffler

    A muffler held to the pipe with bolted flanges will have one of two bolt arrangements securing the flanges together. Look closely at the flange. What looks like a bolt may actually be a stud and will require much more care to remove. Examine both ends of the bolt to see if it or the nut is welded to one flange. If it is, care must be taken to get the nut off without damaging the stud. Use a penetrating oil or heat to help break up rust on the threads before attempting to remove the bolt or nut.

    Some bolts are through bolts and can turn freely in the flange holes once loosened slightly. If you are certain your muffler flange uses these bolts, you may find it is easier to cut them in half and replace them with a new bolt. Use a reciprocating saw or hand hacksaw to cut them.

    Once the flange is unbolted spray the rubber hangers with a light oil, such as WD40 and remove them from the brackets on the muffler. This is easily done with a pair of arc joint pliers.

Removing a Clamped-On Muffler

    Be aware that replacing this muffler will be difficult. You must cut the U clamps off and then separate both ends of the muffler from the pipes. Generally, this will require careful work with a hammer and chisel. An air hammer with a chisel designed to split the pipes is much faster if you have access to this tool, and a cutting torch is much faster, but this is not the place to learn to use one.

    Once the muffler nipple is split, you can work the pipe out of it. It isnt easy to do because of rust and the deformation of the pipe caused by the clamp. Avoid hammering on the pipes, try to remove them with twisting and pulling. It may be necessary to split the muffler nipple in two or three places before the pipe will separate from it.

Installing the New Muffler

    Use a new gasket when installing a flanged muffler. Place the bolts through the flange and use them to hold the gasket while you slide the muffler in place. Tighten the bolts securely but dont over tighten. Finish up by lubing the rubber hangers and pushing them on to the muffler brackets.

    If your muffler is secured to the exhaust pipes with U clamps, it will be necessary to install the muffler on to the pipe a distance equal to the length of the nipple on the muffler. Slide the muffler on while twisting and pushing it in place. If it does not readily slide on to the pipe, you may need to rent a pipe expander and enlarge the nipple slightly. Once the pipes are installed in the muffler ends, install the proper-sized U clamp and tighten securely.

Check your work

    The last step in replacing your own muffler is to start the engine and check for leaks. If any are found simply tighten the clamps or bolts tighter. This should eliminate the leaks.


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