Believe it or not, the biggest mistake professional techs and do it yourselfers make when installing hose clamps is torque-related. We have seen many failures and leaks caused by overtightening the clamp during vehicle operation. This can even cause complete clamp failure during the initial installation. While we realize that most people will not use a torque wrench when installing clamps, here are some specifications we recommend you try. It may take some time, but soon you’ll have a good feel for what proper torque is when installing different types of clamps.
Here are recommended torque values for different NORMA brand clamps.
BREEZE Mini Clamps
These are typically worm drive hose clamps found on small rubber and plastic lines ranging in size from 1/4" to 3/8" diameter. The proper torque for these is 10-15 in. lbs.
BREEZE Power-Seal and AeroSeal Worm Drive Hose Clamps
These are found in sizes from 7/16" to 7" in diameter. The correct torque is 30-45 in. lbs. for the stainless screw versions and 27-35 in. lbs. for the carbon screw versions.
BREEZE CT AeroSeal Clamps
These constant-torque clamps, found in sizes from 9/16" to 3 ¾", should be tightened to 30-45 in. lbs.
BREEZE Constant-Torque Heavy-Duty Clamps
These clamps are found in sizes ranging from 1" to 9 1/8" in size. The torque value for this HD clamp is 90 in. lbs. Let’s take a minute to stress how important it is to use a torque wrench on the constant-torque style clamps. These are designed with a Belleville spring that allows the clamp to expand and contract with temperature fluctuations to prevent cold leaks. They only work properly when they are installed at the proper torque specification.
BREEZE T-Bolt Clamps
These range in size from 1 ¼" to 8 13/16" in size. The correct clamp tightening torque for this is 60 in. lbs. for the clamps with a ¼ screw and 150 in. lbs. for clamps with a 5/16" diameter screw. This specification is for standard and spring-loaded clamps.
BREEZE V-Band Clamps
These range in size from 2.11" to 14" in diameter. The proper torque for the V-Band clamp is 60 in. lbs. for V-Bands with a 1/4 screw and 150 in. lbs. for V-Bands with a 5/16 screw.
Do you need to use a torque wrench to install clamps? We think so if you want a bullet-proof reliable connection that will last. Not installing clamps at the proper torque negates all the testing and durability that was built into the clamp by the manufacturer.