When to use threadlocker and which type to use

Threadlocker fluid is used on suspension and brake fasteners

Carmakers use threadlocker fluids on certain bolts to make sure they don’t loosen. In most cases, those bolts are used in brake and suspension systems because failure of the bolt could be life threatening. If you remove a bolt that was installed with threadlocker, you must clean it and apply fresh fluid when you reassemble.

Where you’ll find threadlocker used in automotive applications

• Brakes — You find it on caliper bracket bolts and caliper slide bolts
• Struts — Some carmakers use it on the large bolts that secure the strut to the steering knuckle and sometimes on the bolts that secure the strut mount to the strut tower.
• Suspension — You’ll sometimes find it on ball joint studs, lateral arm bolts, and unitized wheel bearings

How to use threadlocker

If the bolt originally had threadlocker, it must be removed using a wire brush. Then apply fresh fluid to the threads and install it to the specified torque. If you’re installing a new bolt, apply it to the threads that will be in contact with the nut or threaded portion of the component.

What type of threadlocker to use

Purple — Low strength fluid locks the fastener but allows for easy disassembly

Blue — Medium strength locks the fastener, but allow it to come apart using a fair amount of torque.

Green — High strength wicking formula. Best for pre-assembled fasteners that need extra protection against loosening. Apply it and it wicks down the threads. Requires heat and high torque to disassemble.

Red — High strength permanent. It can’t be removed using torque alone; you must use heat as well. Use for fasteners that you don’t expect to remove.

Permatex High Strength Removable ORANGE GEL

Permatex High Strength Removable Threadlocker
ORANGE GEL is a hybrid formula that combines the strength of Threadlocker RED with the removability of  Threadlocker BLUE. Threadlocker ORANGE GEL is ideal for modern-day engine bays with many lightweight components and high vibration applications. Unlike traditional Threadlocker RED, Threadlocker ORANGE GEL can be removed with hand tools when extra force is applied.

How thread lockers cure

Thread locker products are anaerobic, which means they cure in the absence of oxygen at room temperature. In addition to locking the fasteners, the fluid also seals the threads against leaks and contamination from outside materials. They can actually prevent corrosion by keeping moisture out of the threads and provide a barrier against galvanic corrosion.

For more information on threadlocker strength and cure times, see this chart

©, 2021 Rick Muscoplat