Repair an Exhaust Pipe with a Tin Can

A new exhaust pipe for a car can be very costly. A quick and effective method for temporarily patching a hole in an exhaust pipe is to use a tin can. The readily available exhaust pipe wraps can be ripped apart by exhaust gas pressure when used alone and become more expensive when metal inserts are included (along with stainless steel clamps). But by wrapping a tin can around the hole in an exhaust pipe, a seal can be created that lasts without the cost of labor and new parts, at least until the tin can breaks or burns through. After all there is a reason that exhaust pipes are not made from tin cans - they aren't strong enough, but as a patch the tin can relies on the strength of the pipe and of the multiple clamps to make a trusty temporary fix for a leaky exhaust pipe. The length of time that this patch will last is dependent on the strength of the pipe, the reason for the hole appearing and the toughness of the can material.

Steps

Properly Jacking Up Your Vehicle

  1. Ensure your vehicle jack and jack stands are in proper working order and have the capacity to hold your vehicle prior to beginning the jacking sequence. Use chocks or pieces of wood ahead and behind the last wheel that you intend to jack. For example, if you intend to lift the front of the vehicle, place chocks in front and behind the rear wheels. If all four wheels are to be lifted, set the emergency brake, put the vehicle in Park or in gear and lift the rear wheels first. The decision will be most likely made based on where the repair is to be accomplished. Vehicle exhaust pipes run from the front to the rear on most vehicles (not all).
  2. Find the jack point on your vehicle
    • If you cannot locate the jack point, use the frame of the vehicle or a solid component of the sub-frame.
  3. Use jack to lift the vehicle high enough to be able to work underneath
    • Be cautious. The vehicle might shift if the jack is on wheels and the ground is not reasonably level (flat). If only the rear wheels are lifted, be sure that the emergency brake is set or the vehicle is in Park or in gear to prevent rolling.
  4. Place jack stands underneath vehicle at the frame or solid parts of the sub-frame.
  5. Release pressure from the jack and place most of the vehicle weight onto the jack stands.
    • Once weight is placed on the jack stands, start to pump the jack until it begins to raise the vehicle again. Do this to have 3 points of contact on the vehicle to make it as stable as possible. Don't forget that a hydraulic jack might suffer from leak-down, so re-pressurize the contact point from time to time. If four jack stands are used, one at each corner of the vehicle, the stabilized vehicle should be safest to work under.
  6. Remove handle from jack if possible and set off to the side.

Preparing Materials and Exhaust Pipe

  1. Obtain a tin can. The best tin can to use is a soup can about 4 inches in diameter for the standard 2 - 2.5 inch exhaust pipe. A larger can will be required for larger diameter pipes.
  2. Use tin snips or heavy duty scissors to cut the can up the side and to cut the bottom out of the can. (Note: don't attempt to cut the can with ordinary household scissors. It might work, but the scissors will be destroyed.) The bottom of the can may be removed with an ordinary can opener so that the bead is retained for strength purposes.
    • Be very careful cutting the can, the edges are extremely sharp. Wear thick gloves such as leather gloves or even a good grade of mechanics gloves (not nitrile 'rubber' gloves).
  3. Set the cut can off to the side where it won’t be in the way.
  4. Use a steel wire brush to brush off any debris on the tail pipe that will hinder the seal of the can against the exhaust pipe. Note that the can should also be clean inside, but the picture is referring to the exhaust pipe, not to the can - remember, we set it aside a moment ago.
    • Safety glasses are recommended for all steps, but are essential for this step because you are below the exhaust pipe you are cleaning. Floating debris seldom falls straight down, it swirls in any air current that is present - inevitably into your eyes.
    • If there is any concern that the pipe is not going to allow sealing between the can and the pipe due to flaky material or uneven surfaces, a good sealant for exhaust joints should be used - something that will withstand 2000 degrees F or so. Now is the time to decide, not after you are unable to get the seal to occur.

Wrapping the Can Around the Exhaust Pipe

  1. Form the can to the shape of the exhaust pipe centered over the hole, and where the two edges will overlap, providing a double-thickness of material over the hole. If the hole is too large, this won't suffice as a fix. Also if the material is found to be weakened more than just along the bottom or about one third of the diameter of the pipe, the pipe will be too weak to withstand the clamping step.
  2. Unscrew completely 5 #28 hose clamps so that they can be placed around the can.
  3. Place all 5 of the clamps equally spaced across the length of the can.
  4. Begin to screw the clamp on one of the ends until the clamp can no longer move. Make sure that the edge of the can is sliding under the other edge on both ends of the can as the clamps are tightened.
  5. Begin to screw the next clamp until the clamp can no longer move. Continue this until all clamps can not move.
  6. Return to the first clamp and tighten until the clamp cannot be tightened anymore. Continue this step for the remainder of the clamps.
    • When clamps are completely tightened, the screw may skip and loosen depending on the diameter of the exhaust pipe. If this occurs tighten clamp again to a point it will not skip and loosen again.
  7. Make sure that the transmission is in neutral (standard transmission) or Park (automatic) and start the vehicle to determine whether the exhaust leak has been fixed.
    • If the exhaust leak is still present, recheck the clamps to ensure all are tight and ensure the can is completely covering the hole in the exhaust pipe. If the pipe is too weak to support the clamps, the pipe might have collapsed inside during tightening, reducing the diameter of the original pipe.
    • Feel around the edges of the patch without touching the material as the engine is idling to sense any escaping hot gases (turn sensitive portion of your hand nearest the pipe). If you can feel the gases escaping, chances are that the seal is not going to hold for long. You can either take your chances or redo the procedure using a sealant putty designed for exhaust joints.
    • Another alternative is to use one of the wraps that tend to blow open and wrap the can around the installed wrap to provide a strong positive seal. However, if the pipe is too deteriorated, it is time for a new pipe.

Lowering The Vehicle

  1. Raise the jack to where the vehicle is lifted off the jack stands one at a time.
  2. Remove the jack stands from under the vehicle as they are released.
  3. Slowly lower the vehicle back onto the tires one at a time.
  4. Remove the jack from under the vehicle.

Tips

  • Ensure the jack you have can lift the weight of the vehicle, approximate rating of one half the vehicles curb weight.
  • Make sure your jack and jack stands are in proper working order. Use four stands if at all possible.
  • The more straight the can is cut up the side, the easier it will be to wrap around the exhaust pipe. But if the can is cut on a 15 degree angle, the seal will tend to be stronger since it is not in line horizontally, but will still be relatively easy to wrap. But the cut should still be uniformly straight.
  • Seriously consider purchasing a sealant compound to assure the seal is complete between the can and the pipe especially if the pipe is deteriorated where the can contacts the pipe.

Warnings

  • If you don't feel confident in your abilities to do this, do not attempt to do it.
  • Serious injury or death by crushing is a risk if vehicle is not properly supported.

Things You'll Need

  • 1 steel wire brush
  • 1 hydraulic floor jack; 1.5 T for a 3 T vehicle (sedan), 3 T for a larger pickup
  • 2 jack stands; four jack stands is best, but more work
  • 1 suitable can, such as a soup can
  • 1 pair of tin snips or heavy duty scissors
  • 5 #28 hose clamps, that is, clamps large enough to circumvent the patched pipe
  • 1 pair of heavy duty gloves, leather or good grade mechanics gloves
  • 1 pair of safety glasses; these are to be used, not to sit on.
  • 1 flat blade screw driver or hex nut driver of appropriate size
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