Forum Members Suggest Proper Torquing Techniques
Ensure you are accurately tightening your Mustang's fasteners to the manufacturer's precise torque specifications with these tips and techniques.
A Proper Tightening Strategy
An often overlooked procedure when doing any kind of work on your Mustang is properly torquing down the fasteners to the appropriate specifications outlined by the manufacturer. More often than not individuals use the old German 'Gutentight' method to snug down various nuts and bolts, but this can often lead to the fastener fatiguing, loosening, or even failing over time. For safety and peace of mind, using your torque wrench to properly tighten things down will serve you and your car best in the long run. Here are some tips that can help out when using a torque wrench in the future.
Beam vs Dial
Torque wrenches come in several different styles including beam, dial, click-type, and digital. Beam wrenches are designed with a material that flexes as force is applied, but a stationary arm sits over a gauge that indicates the torque value. The beam torque wrench is typically the most durable and inexpensive type of torque wrench but tends to be the least accurate. Dial torque wrenches indicate the torque value with a needle on a round analog dial, which is typically more accurate than a beam wrench, but minor variances in torque values can occur from parallax error when reading the gauge. These can be offered with a type of light or buzzer that indicates a specific torque or even have a second needle that acts as a "memory" function for the torque that was applied.
Click vs Digital
Click-type torque wrenches allow users to set the wrench to the specified torque value before tightening a fastener. The wrench will then break-over or "click" when the preset torque value is reached. These often provide the best bang for the buck in terms of accuracy and durability for a relatively cheap price. The digital torque wrench is the most costly, yet typically the most accurate type of torque wrench on the market today. These electronic wrenches use a strain gauge to measure the force applied and generally have a margin of error of less than 1%. These wrenches have all the bells and whistles such as a memory function, audio indicators, different units of measurement, and more.
The Right Tool for the Job
Choosing the correct tool for the job is a motto to live by when doing any type of automotive work, and this is especially true when using a torque wrench. Torque wrenches come in various sizes and working ranges thus a small 1/4" drive inch-pound torque wrench just isn't gonna cut it when having to tighten lugs nuts to 100 foot-pounds. In general, mechanical torque wrenches have an accurate working range of 20-100% of their scale and digital wrenches 10-100% of their scale, so choosing the appropriate size wrench that will tighten your specific fastener within its working range will yield the best results.
Fastener Prep
So you have the proper torque wrench picked out and you know Ford's suggested torque specification for the fastener you intend to tighten, but does that fastener require any lubrication be applied to the threads? Lubrication greatly affects the coefficient of friction when tightening a nut or bolt. Some sources indicate that a lubricant such as anti-seize can alter the torque reading by as much as 40%. Be sure to check whether Ford intends for the fastener to be installed dry or with a lubricant such as oil, anti-seize, or even threadlocker compound applied to the threads.
In Stages or All At Once?
A torque wrench should not be used as a primary tightening device to run a nut or bolt down, but instead used only as a tool to achieve the final torque value. Fasteners should be torqued to specification in one single pull unless otherwise stated. For parts like cylinder heads or wheel lugs nuts (or any torque + angle spec), torque should be applied in a specific sequence and increasingly tighter until the correct values are achieved.
The Correct Form
Utilizing the proper technique when using a torque wrench in crucial to achieving an accurate reading. Grab the torque wrench in the middle of the handle area and pull in a slow manner to avoid any quick, sharp, or sudden jerks in movement. When the correct value is achieved as indicated by the torque wrench, immediately let up to avoid over-tightening of the fastener and potential damage to the torque wrench.
Care and Maintenance
Once you are finished with your torque wrench it is important that it is stored in a safe place. If applicable, be sure to back-off any tension on the wrench to its lowest setting before storing it. Do not expose it to temperature extremes, high humidity, or allow it to be immersed in any type of liquid. Be gentle with the wrench as dropping or sliding it can have an impact on its calibration. Many manufacturers recommend the torque wrench be inspected and recalibrated every 5,000 cycles to ensure accuracy. In short, if you take care of your wrench, it will take care of you for years to come.