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  • Before beginning work on an exhaust system, make sure it is cool to the touch.
  • Some technicians disconnect the battery's negative cable before starting to work to avoid short-circuiting the electrical system.
  • Soak all rusted bolts, nuts, and other removable parts with a good penetrating oil.
  • Check the system for critical clearance points so they can be maintained when new components are installed.
  • Most exhaust work involves the replacement of parts. When replacing exhaust parts, make sure the new parts are exact replacements for the original parts. Doing this will ensure proper fit and alignment, as well as ensure acceptable noise levels.
  • Exhaust system component replacement might require the use of special tools and welding equipment.
Special tools required for exhaust work.
  • Be sure to support all parts of the exhaust system while performing maintenance.
  • Clamps help to secure exhaust system parts to one another. The pipes are formed in such a way that one slips inside the other. This design makes a close fit. A U-type clamp usually holds this connection tight, as seen below.
A U-type clamp is often used to secure two pipes that slip together.
  • Another important job of clamps and brackets is to hold pipes to the bottom of the vehicle. Clamps and brackets must be designed to allow the exhaust system to vibrate without transferring the vibrations through the car.
  • There are many different types of flexible hangers available. Each is designed for a particular application. Some exhaust systems are supported by doughnut-shaped rubber rings between hooks on the exhaust component and on the frame or car body. Others are supported at the exhaust pipe and tailpipe connections by a combination of metal and reinforced fabric hanger. Both the doughnuts and the reinforced fabric allow the exhaust system to vibrate without breakage that could be caused by direct physical connection to the vehicle's frame.
Rubber hangers are used to keep the exhaust system in place.
  • If the vehicle's system is welded, cut the pipe at the joint with a hacksaw or pipe cutter. The new pipe need not be welded to the muffler. An adapter, available with the pipe, can be used instead. When measuring the length for the new pipe, allow at least 2 inches (50.8 mm) for the adapter to enter the muffler.
  • When trying to replace a part in the exhaust system, you may run into parts that are rusted together. This is especially a problem when a pipe slips into another pipe or the muffler. If you are trying to reuse one of the parts, you should carefully use a cold chisel or slitting tool on the outer pipe of the rusted union, as illustrated below. You must be careful when doing this, because you can easily damage the inner pipe. It must be perfectly round to form a seal with a new pipe.
Removing a rusted-on muffler.

Be sure to wear safety goggles to protect your eyes and work gloves to prevent cutting your hands on the rusted parts.

  • Slide the new pipe over the old. Position the rest of the exhaust system so that all clearances are evident and the parts aligned, then put a U-clamp over the new outer pipe to secure the connection.