Most everyone is familiar with the common tools every automotive technician uses on a daily basis. Ratchets, sockets and wrenches come to mind. One of the most important tools that you may not know of is called a torque wrench. In actuality it is not really a wrench at all but rather a very sensitive ratchet which allows the technician to dial in the proper torque force to the fastener.
What is "torque"?
The simple definition of torque is the exact amount of twisting force applied to an object. In the case of the automotive repair field it is generally the amount of twisting force applied to nuts and bolts required to reassemble vehicle components.
How does this affect my car?
The improper amount of applied torque to fasteners in your car can negatively affect your vehicle. Vehicle manufacturers such as BMW, Audi and Mercedes have specific torque specifications for almost every nut and bolt in your vehicle. When fasteners are under or overtorqued it can have adverse affects. For example the torque specification for your lug bolts that hold your wheel to the hub is usually around 90 foot pounds. If the lug bolts are undertoqued you may run the risks of your wheel falling off while you're driving! If the bolts are over torque it can cause warping of the brake rotors, imbalance of your wheels, and seizing of the lug bolts. Seizure of lug bolts can cause a problem changing a flat tire. Every so often at M-Spec Performance we find that some vehicles have over torqued lug bolts which require special extractors to remove seized bolts.
Should I trust a shop that doesn't use a torque wrench?
The short answer is no. Especially on German cars, torque specifications are very important. They can mean the difference between a job well done and leaky gaskets or even engine failure during very delicate engine operations. Proper torque as well as the right tools for the job can also show that the workshop is a professional repair facility ready and a willing to follow the proper repair procedures. Torque wrenches are also not inexpensive. Quality torque wrenches can exceed $600 for one wrench! There are also different sizes and lengths as well as specialty torque wrenches. A proper repair facility should employ all of them.