BMW 340i 2005-2011 Body & Frame Bolt Torque Specifications

Correct torque ensures proper clamping force, preventing loosening due to vibration, stress, or thermal expansion. Insufficient torque can lead to parts rattling or even falling off, while excessive torque can strip threads or damage components. For example, improperly torqued fender bolts could cause the fender to misalign or vibrate, leading to premature wear or damage.

Overtightening can strip the threads in the receiving nut or mounting point, damage the bolt itself, or even deform the surrounding body panel. This requires repairing the stripped threads (using a thread repair kit) or replacing damaged parts, and may cause misalignments in the body panel. For instance, overtightening a door hinge bolt could make it impossible to adjust the door correctly.

In most cases, threadlocker is not necessary for body bolts, as the specified torque provides sufficient holding force. However, if a bolt is consistently loosening due to vibration (as sometimes happens with trunk lid or spoiler attachments), a medium-strength (blue) threadlocker can be used as a preventative measure. Avoid using high-strength (red) threadlocker unless specified by the manufacturer, as disassembly could become difficult or damage the threads. Example: If the mounting bolts of a spoiler continually loosen, you can try adding a small amount of blue threadlocker.

Generally, body bolts can be reused unless they show signs of damage, corrosion, or stretching. If you're unsure, or if the bolt was particularly difficult to remove, it's best to replace it with a new one of the same specification. New bolts ensures optimal holding strength, and the cost is minimal compared to the potential consequences of bolt failure. An example is the bolts holding the bumper; while they can usually be reused, if they show any sign of bending or corrosion replace.

For regular maintenance, checking the torque on body bolts is not necessary unless you've been working in that area. If you've recently removed and reinstalled body panels or components, it's good practice to re-check the torque after a few drives. This is particularly important after significant road vibration like off-roading or bumpy road conditions. Example, after removing and reinstalling the front bumper check the torque after the first 200 miles.