If you’re a mechanic, here’s where you’d typically use Big Dog Threadlockers 271, 243, 242, and 222 in automotive and mechanical applications:
1. BD271 (Red – High Strength, Permanent)
Application: Used where fasteners must not loosen and require heat (450°F+) for removal.
Common Uses for a Mechanic:
- Cylinder head bolts
- Main and rod bearing cap bolts
- Flywheel bolts
- Suspension and frame bolts
- Ring gear bolts
- Crankshaft pulley bolts
- Driveshaft and axle nuts
Note: Only use 271 when you don’t expect to remove the fastener frequently. Heat and tools will be needed to break the bond.
**While 271 is considered a “permanent” bond, for critical fasteners we still highly recommend safety lock wiring – especially if you are going to the track.
2. BD243 (Blue – Medium Strength, Oil-Resistant)
Application: Similar to BD242 but with better oil resistance, so it works on oily surfaces.
Common Uses for a Mechanic:
- Brake caliper bracket bolts
- Transmission pan bolts
- Oil pan bolts
- Differential cover bolts
- Timing cover bolts
- Water pump bolts
- Motorcycle handlebar and suspension fasteners
Note: Can be removed with standard hand tools, making it ideal for components that require occasional disassembly.
3. BD242 (Blue – Medium Strength, General-Purpose)
Application: Prevents vibration-induced loosening but allows for hand-tool removal.
Common Uses for a Mechanic:
- Valve cover bolts
- Throttle body and intake manifold bolts
- Power steering pump bolts
- Alternator and starter motor bolts
- Body panel and bracket bolts
- Motorcycle fairing and frame bolts
Note: Works well on clean, dry fasteners but isn’t as effective on oily or contaminated surfaces compared to 243.
4. BD222 (Purple – Low Strength, Small Fasteners)
Application: Designed for small screws where you want to prevent loosening but require easy removal.
Common Uses for a Mechanic:
- Carburetor and throttle body screws
- Electrical connectors and small screws
- Interior trim and dashboard screws
- License plate bolts
- Motorcycle controls and levers
- Small engine parts
Note: This is great for delicate or low-torque fasteners that you don’t want to overtighten.
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