Know-How Notes: Exhaust Clamps and Hangers
Unless you have to replace the entire exhaust system, basic maintenance of your vehicle’s exhaust system can be done with just a few hand tools and the right parts. But what parts are the right parts? There all kinds of different components in the exhaust. The big pieces—mufflers, pipes, and catalytic converters require cutting and welding in most cases, so you may not want to tackle that yourself (though you certainly can). These major components are not part of the general maintenance regime, which includes exhaust gaskets, exhaust clamps, and exhaust hangers.
Eventually, these parts will fail, usually before the major components. Gaskets and hangers are the most common replacement parts for typical exhaust system, hangers are usually replaced as part of servicing the other two components. There are several types of each; this article should help you make heads or tails of what you have and what you need. We will cover gaskets in another article, this article is focused on hangers and clamps.
Factory hangers range from vehicle-specific to universal. You may be surprised to find out that most vehicles use universal-style hangers as opposed to the vehicle specific ones. This is because it is much easier (that means cheaper) for an auto manufacturer to simply use an off the shelf parts for the exhaust than spend hundreds of hours developing and manufacturing a bracket and hanger for one car model. There are some cars that use very specific hangers, this was a common practice in the late 1980s to early nineties.
Most modern vehicles use a readily-replaceable hanger system that consists of two pegs and a rubber isolator bushing. The pegs look like exaggerated arrows, the large cone shaped tip passes through the isolator, but can’t slide back off. These isolators suspend the exhaust from the chassis, while absorbing vibrations so the exhaust system is quiet and does not rattle. These have become the most popular style of hanger. One peg is welded to the tubing, while the other is typically welded to a small bracket that it bolted to the chassis itself. The positions are vehicle-specific, but the isolators are generally universal. There are different sizes to match the factory isolator.
Older vehicles use the other style of universal hanger. These are a combination stamped steel brackets with a belted rubber strap. There are many different shapes and sizes of these strap hangers, many are brand and model specific, but they are still universal because they cover a wide range of vehicles and can be used in other applications. The truly universal strap hanger is a single strip of rubber with a several equally-spaced holes in it (this is the part that bolts to the chassis), and a single metal bracket on one end which is designed to be secured using a U-bolt exhaust clamp. When changing these style of hangers, it is a good idea to replace the clamp as well.
There are numerous style of exhaust clamps, and the type that your vehicle’s exhaust system uses depends on the car. The main types are ball and socket, U-bolt, flat band, and V-band clamps. Each have their place in the exhaust system and you may find 2 or more styles of clamp on your factory system.
This is the most common type of exhaust clamp, even though it is the worst one. So many aftermarket exhaust systems use these types of clamps, even factory systems have used them. They are not bad, they are certainly functional and useful for hangers and slip-fit pipe connections. They get the job done when properly installed. The problem arises when you need adjust or remove a section of the exhaust for service, such as drivetrain or rear suspension repairs. The small diameter of the clamp crimps the pipes together, so you can twist them, but usually you can’t actually separate the tubes. If you don’t get the clamp tight enough to crimp the tubes, they leak.
Ball and Socket
This is not quite a clamp, but also not a flange. Just like it sounds, there is a rounded ball end that fit inside a flared socket end of pipe. The two halves are compressed together with a two or three-bolt ring on either side of the joint. This is a gasket-less connection that is quite common on factory exhaust systems, particularly used between the exhaust manifold and the catalytic convertor. The cat is a service piece, so they have to be easily removable. The ball and socket can be reused over and over again, so it works really well. These can be bought as weld-on sections for custom exhaust as well.
The band clamp is a wide strap of metal, typically stainless or mild steel, which wraps around the exhaust pipe joint. These come in two subtypes, a pre-formed ring or a flat strap that you wrap around the pipe and bolt together. The pre-formed type is now more commonly used in higher-end aftermarket exhaust systems using slip-fit, whereas the flat band strap clamp is sold a “sealing clamp”, designed for use in butt-joint seams. The biggest benefit of this style is ease of use, they are relatively cheap, and are reusable without damaging the pipes. You can easily remove the system for service and reinstall everything without cutting anything.
If your last name is Warbucks or Rockefeller, then you can afford V-band clamps. All jokes aside, these things are really expensive, easily fetching $20-30 each (and much more), but if you have a high-end vehicle with a turbo, they are worth it. Typically these clamps are used on turbo exhaust systems, because they are easy to work with, seal better than anything else, and look good. Each clamp consists of two machined interlocking rings that get welded to the pipes, and a large outer ring that sandwiches the two rings together for a perfect leak-free seal. If you are building a custom exhaust system and you may need to remove it later, or want a high-end look, dropping a few hundred bucks on some stainless steel V-band clamps may be worth the price. Is it overkill for a daily-driver Accord or Saturn? Yes. Does it look cool anyway? Absolutely.
Servicing your vehicle’s exhaust system is not the most glamorous task. If you have a worn out exhaust hanger or busted exhaust clamp, fix it as soon as possible, otherwise you could be shelling out big bucks replacing the entire system after you drive over it on the freeway.
Check out all the exhaust system parts available on NAPA Online or trust one of our 16,000 NAPA AutoCare locations for routine maintenance and repairs. For more information on exhaust clamps and hangers, chat with a knowledgeable expert at your local NAPA AUTO PARTS store.