Copper Washer for Differentials & Series 1-2a Gearbox Drain Plugs
Sealing washer designed for differential and gearbox drain plugs. Positioned between the plug and the housing, it ensures a leak-tight seal across front, rear differential, and axle drain setups. This component is also widely known as a drain plug washer or sealing washer.
Fits Filler/Level Plug AF-533358.
Alternative to fibre washer AF-FRC4835.
Supersedes CS-230509.
Notes: The original "crushable" washer is no longer available.
515599 is a standard, solid flat copper ring which relies on straightforward flat face sealing under high clamping torque. It is very similar to FRC4089 but not exactly the same. FRC4809 is crush style copper washer designed for lower torque applications where deformation is needed to seal lighter aluminum/cast gearbox casing faces without stripping threads.
To be completely honest, they are likely interchangeable. No matter which one you use, your Land Rover will likely still leak. If's it's not leaking, it's empty.