Thread Lockers and Sealants

Track Cars see incredible vibration and expansion/contraction of bolted assemblies. This causes fasteners to loose their torque and eventually fail. The old way of retaining fasteners was castle nuts with pins, lock washers, and safety wire. The new way is with chemical thread lockers. At 3DM Motorsport we use Loctite thread lockers on virtually every fastener in a racecar. LOCTITE is the world’s leading brand for adhesives and sealants.

In addition to thread locking, Loctite also performs multiple other functions. Loctite acts as a lubricant when torquing fasteners which ensures proper torque specifications are obtained. This is similar to the concept of oiling cylinder head and crank bolts before installation. Loctite also acts like an anti seize. As the bolt is installed the loctite is distributed through all of the mictroscopic gaps in the threads. Once it cures it essentially seals the threads disallowing any moisture and oxygen to start the corrosion process.


Loctite Automotive Catalog

Click the image below to view the all of Loctite's available products and their uses on automobiles. You will find there are a lot of products available and it is not cost effective to have them all on hand. Below, we have put together a reference guide of the most common used products that we use when assembling racecars. Keeping these on hand won't break the bank and will cover 95% of all thread and flange sealing needs on your automobile.

 
 

Loctite Products most commonly used

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Loctite® 222

We typically use this compound on data sensor mounting hardware, dash display mounting hardware, body panel hardware, etc.

 

Color: Purple
Strength: Low
Bolt Size: Set screws and bolts up to 6mm
Technical Data Sheet

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Loctite® 243

This is by far the most commonly used thread locker and we keep a big bottle of this around. We used to keep the traditional Loctite 242 on hand but 243 accomplishes the same thing with the added benefit of higher oil resistance. No need to keep them both around.

Color: Blue
Strength: Medium
Attributes: Oil resistant
Typical Bolt Size: 6mm up to 22mm
Technical Data Sheet

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Loctite® 263

We use this on flywheel bolts and axle nuts. We used to keep the traditional 262 on hand but Loctite 263 accomplishes the same thing with the added benefit of higher oil resistance. Again, No need to keep them both around.

 

Color: Red
Strength: High
Attributes: Oil resistant
Typical Bolt Size: 6mm to 22mm
Technical Data Sheet

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Loctite® 272

We keep a bottle of this around for one purpose... wheel studs. Brakes get very hot and the heat transfers into the wheel hub where the studs are retained by Loctite. The added temperature resistance of Loctite 272 helps ensure we don't have wheels studs coming loose.

Color: Red
Strength: High
Attributes: Temp resistant to 450F
Technical Data Sheet

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Loctite® 290

This is for fasteners that are already installed as it "wicks" into the threads. We rarely if ever use this but it is nice to have on hand "just in case."

Color: Green
Strength: Medium to High
Attributes: Wicking for already assembled fasteners
Technical Data Sheet

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Loctite® 518

This is a medium-strength, general purpose gasketing product with excellent contamination tolerance. Ideal for use on cast iron, steel and aluminum flanges such as differential covers, oil pans, thermostat housings, etc.

Color: Red
Strength: Medium
Attributes: Gel type consistency
Technical Data Sheet

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Loctite® 7649

This is designed to promote the curing speed of LOCTITE anaerobic adhesives and sealants without any significant loss of joint strength. We use this track-side and/or when a newly assembled fastener needs to be used immediately.

Color: Clear
Attributes: spray
Technical Data Sheet


Accessories

These are hand-held bottle-top applicators that mount easily on any Loctite® 50 or 250 ml bottle. It will not leak regardless of the orientation of the bottle which minimizes waste and converts the product package into a portable dispenser. These are pricey and not really worth it but nice to have if you do a lot of assembly work. Part # 97001 for 250 ml bottle and 98414 for 50 ml bottle

 


Assembly and Disassembly Tips

For Assembly

  • For best results, clean all surfaces (external and internal) with a LOCTITE cleaner and allow to dry. (Brake clean works well for this)
  • If the material is an inactive metal or the cure speed is too slow, spray all threads with an activator such as LOCTITE 7649 and allow to dry. 
  • Shake the product thoroughly before use. 
  • To prevent the product from clogging in the nozzle, do not allow the tip to touch metal surfaces during application. 
  • For through holes, apply several drops of the product onto the bolt at the nut engagement area. 
  • For blind holes, apply several drops of the product down the internal threads to the bottom of the hole. 
  • Assemble and tighten as required. 
  • For Sealing Applications, apply a 360° bead of product to the leading threads of the male fitting, leaving the first thread free. Force the material into the threads to thoroughly fill the voids. For bigger threads and voids, adjust product amount accordingly and apply a 360° bead of product on the female threads also. 

For Disassembly 

  • Remove with standard hand tools. 
  • In rare instances where hand tools do not work because of excessive engagement length or because a high strength product was used, apply localized heat to nut or bolt to approximately
    250°C.
  • Disassemble while hot.