ACHIEVING THE PROPER TORQUE

Now that I have been away from the day to day activity of diagnosing and repairing vehicles for almost 15 years, I have the opportunity to view those times from a different perspective. We have all heard the phrase "can't see the forest for the trees". How true that is when we are in the thick of the battle. When working on a vehicle in a retail environment more often than not, time is the enemy. Getting the job done and out the door becomes the top priority and that is when mistakes happen. I know because I made my fair share. Broken bolts, stripped threads, snapped brackets. Some say it’s the nature of the business but most of us know it can be avoided.

Our Tech Line fields in the neighborhood of 250 calls a day. The nature of the inquiries range from pricing and availability to diagnosing failed emission tests and P0420, catalyst efficiency, codes. The number one complaint, however, is the breaking of exhaust clamps during installation. The most interesting aspect of this issue is that although we get many of these complaints every day we know that we are only seeing the tip of the iceberg. As a technician it was clear to me that in most cases when a clamp breaks during installation, phone calls are not being made to the manufacturer to get another clamp. We take off the broken one and get one off the shelf, complete the job and move on to the next vehicle. It became clear that we needed to address this issue.

Over the last couple of years we have done exhaustive studies on the clamps that we use as well as testing of other brands. We have even changed the suggested torque spec. Yet breakage still occurs at an unacceptable rate.

The use of stainless steel in exhaust has changed the game. It is not as forgiving as aluminized and therefore is resistant to crimping. No longer can we put an air wrench on a clamp and spin it down till the pipe crimps. The clamp will give out before that happens. The type of clamp we use and the torque spec we recommend are specifically designed to give you the ultimate seal and longevity on that connection. Below are the results of our testing.

Clamp: 2.5" TORCA (part #103916)

Manufactures Torque spec – 55nm (41ft lb)

30 samples tested on a 2.5" stainless steel slip joint

Results: No failures at spec.  When pushed to the limit, the average failure point was 99 ft lb

Like most issues in the shop, broken exhaust clamps can be avoided when the proper technique is employed.