The exhaust system is has individual sections that are connected together either by a weld or a series of clamps. In some cases, the vehicle will have a clamp attached to a weld point for an extra support. This is the job of the exhaust clamp on most cars, trucks, and SUVs made since the 1940’s.
Exhaust clamps are just metal clamps that are made to hold and seal together different components of the exhaust system. They come in different shapes as well as different sizes to accommodate different types of exhaust pipes, and can usually be tightened or loosened according to need.
Symptoms of a Bad or Failing Exhaust Clamp
If your exhaust is noisy, loose, or is failing an emissions test, you might need to replace an exhaust clamp.
When the clamps fail or have any kind of issue, it can cause problems with the vehicle’s exhaust system, which can affect engine performance. Mostly, a bad or failing exhaust clamp will produce a few symptoms that can alert the driver of a potential issue.
1. Noisy exhaust
One of the first symptoms of a bad or failing exhaust clamp will be a noisy exhaust system. If one of the vehicle’s exhaust clamps fails or has an issue it can lead to a loud exhaust because of an exhaust leak. The exhaust might ring noticeably louder at idle, and noticeably louder during acceleration.
2. Loose exhaust components
Another symptom of a problem with an exhaust clamp is loose exhaust components. The exhaust clamps are made to hold together and seal the exhaust systems pipes. When they fail, it can lead the the exhaust pipes to come loose, which can cause them to rattle and sometimes even hang visibly beneath the vehicle.
3. Failed emissions test
Another symptom of a problem with the exhaust clamps will be a failed emissions test. If any of the exhaust clamps fail or come loose, an exhaust leak can form which will affect the vehicle’s emissions output. An exhaust leak can disturb the vehicle’s air-fuel ratio, as well as its exhaust stream content – both of which can result in a vehicle failing an emissions test.
How to Replace an Exhaust Clamp
An exhaust pipe is supported with the help of exhaust clamps within a vehicle. A bad clamp can lead to exhaust leaks that can turn hazardous if taken care of.
Part 1 of 2: Replacing an exhaust clamp
In many cases, the symptoms you might notice of a bad clamp are actually caused by exhaust system cracks or holes that, once again, can’t be repaired or fixed by an exhaust clamp. The only time you need to replace the clamp is when the clamp has broken or is wearing out BEFORE it has caused the exhaust pipes to crack.
If the exhaust clamp is broken or worn out, there are a few things you require to do before taking on this job:
- Get the right clamp. There are several types of exhaust clamps, but it’s important that you get the right size and style of clamp for your specific application. Look in your vehicle’s service manual if you’re replacing an OEM clamp, or contact the aftermarket part supplier if you are replacing an aftermarket exhaust clamp.
- Verify about the right circumference. There are different sizes of exhaust pipes, and it’s incredibly important to match it with the right sized exhaust clamp. Make sure to physically measure the circumference of the exhaust clamp to verify that it matches the exhaust pipe where it is being installed. Installing the wrong sized clamp can lead to additional damage to your exhaust system and may lead to the need for a complete exhaust system replacement.
- Flashlight or droplight
- Clean shop rags
- Boxed end wrench(s) or ratchet wrench set(s)
- Impact or air wrench
- Jack and jack stands
- Replacement exhaust clamps specific to your needs (and any appropriate gaskets)
- Torque wrench
- Steel wool
- Penetrating oil
- Safety equipment (i.e., safety glasses and protective gloves)
- Service manual which is specific to your vehicle (if you are replacing a clamp used in an OEM application)
- Wheel chocks
- Note: According to most service manuals, this job will take atleast about an hour to complete, so make sure that you have adequate time set aside. Also make sure that you’ll have to raise your vehicle in order to have clear access to the exhaust clamps. If you are having the access to a vehicle lift, use this so you can stand underneath the vehicle, as this will make the job much easier to complete.
Step 1: Disconnect the vehicle’s battery. Even if there are not many electrical parts that are touched when replacing exhaust clamps, it’s a good habit of always disconnecting the battery cables when doing any service to your vehicle that involves removing parts.
Remove the positive and negative battery cables and set them away where they cannot make contact with any type of metal.
Step 2: Raise and secure the vehicle. You’ll be working underneath the vehicle, so you will have to raise it with jacks or use a hydraulic lift if you have access to one.
Be sure to place wheel chocks around the tires on the side of the vehicle you won’t be lifting for support. After that, jack up the other side of the vehicle and secure it on jack stands.
Step 3: Locate the damaged exhaust clamp. There are some mechanics that advice to start the vehicle to find the exhaust clamp that is damaged, but that is very dangerous, especially when the vehicle is raised in the air. Complete a physical inspection of the exhaust clamps to locate those that are loose or broken.
- Warning: If during your physical inspection of the exhaust clamps, you notice any cracks in the exhaust pipes or holes in rusted pipes, stop and contact a professional mechanic to replace the exhaust pipes in question as soon as possible. If the exhaust clamp is damaged and has not broken the exhaust pipe or the welds, you might proceed.
Step 4: Spray the bolts or nuts on the old exhaust clamp using penetrating oil. Once you locate the damaged exhaust clamp, spray the nuts or bolts that are holding the clamp onto the exhaust pipe with penetrating oil.
Since these bolts are exposed to the elements which are under your vehicle, they can easily become rusted. Taking this quick extra step can help to reduce the potential of stripping nuts and bolts which could lead to you having to cut off the clamp and potentially damaging the exhaust pipes.
Let the penetrating oil soak into the bolts for atleast five minutes.
Step 5: Remove the bolts on the old exhaust clamp. With an impact wrench (if you have one) and the appropriate socket size, remove the bolts or nuts while holding the old exhaust clamp in place.
If you don’t have an impact or air wrench, just use a manual ratchet and socket or boxed end wrench to remove these bolts.
Step 6: Remove the old exhaust clamp. As soon as the bolts have been removed, you can take the old clamp off the exhaust pipe.
If you have a clamshell-type of clamp, just pry the two sides off the exhaust pipe and remove it and a U-shaped clamp will come off easily.
Step 7: Inspect the clamp area on the exhaust pipe for any crack or leak in the system. Sometimes, small cracks might be present underneath the exhaust clamp when it’s removed. If this is the case, ensure these cracks are serviced by a professional or the exhaust pipe is replaced before installing a new exhaust clamp.
If the connection is good, just proceed to the next step.
Step 8: Clean the clamp area with steel wool. The exhaust pipe can be rusted or corroded. In order to verify that the connection with the new exhaust clamp is secure, lightly clean the surrounding area of the exhaust pipe using a steel wool.
Do not get aggressive with the steel wool, just ensure to dust off any debris that will hinder the connection of the new exhaust clamp.
Step 9: Install the new exhaust clamp. The installation process is unique depending on what type of clamp you are using. In most cases, you’ll be using a U-shaped exhaust clamp.
For installing this type of clamp, place the new U ring over the exhaust pipe in the same direction as the U ring from the old clamp. Put the support ring on the other side of the exhaust pipe. While holding the clamp in place with one hand, screw one nut onto the threads of the U ring and hand tighten it till you reach the support ring.
Install the second nut on the other side of the clamp in the same manner, ensuring to hand tighten it until you reach the support ring.
Tighten the nuts further with an end wrench or ratchet. Use a progressive method for tightening these bolts to make sure that one side is not tighter than the other; you want a clean connection on the exhaust clamp. Do NOT tighten them using an impact wrench as it may twist the exhaust clamp, which is way it’s best to install these nuts with a hand tool.
Tighten the exhaust clamps fully using a torque wrench. You can find the recommended torque settings in the vehicle’s service manual.
- Tip: Many certified mechanics will always finish tightening important nuts that are attached to studs using a torque wrench. By using an impact or air tool, you might cause the bolts to be secured higher than the torque settings. You should always be able to turn any nut or bolt at least by ½ of a turn with the torque wrench.
Step 10: Prepare to lower the vehicle. Once you’re finished tightening the nuts on the new exhaust clamp, the clamp should be successfully installed on your vehicle. You then need to clear all tools from under the vehicle so that you can lower it.
Step 11: Lower the vehicle. With your jack or lift, lower the vehicle to the ground. If you are using a jack and jack stands, just raise the vehicle slightly first to remove the jack stands, and then proceed towards lowering it.
Step 12: Reconnect the vehicle’s battery. Reinstall the negative and positive battery cables into the battery for restoring power to the vehicle.
Part 2 of 2: Testing the repair
Most of the time, testing the vehicle after completing an exhaust clamp replacement is quite simple.
Step 1: Visually inspect the exhaust pipes. If you found earlier that the exhaust pipes were hanging low, and you can physically see that they are no longer doing this, then the repair was successful.
Step 2: Listen for excessive noise. If the vehicle was previously making excessive exhaust noise earlier, and now when you start the vehicle the noise is gone, a successful replacement of the exhaust clamp was completed.
Step 3: Test drive the vehicle. As an added measure, it is a good to road test the vehicle with any audio off to listen for any noise coming from the exhaust. If an exhaust clamp is loose, it will mostly create a rattling sound under the vehicle.