I am re-consolidating my trail toolkit and decided to check what ChatGPT says about common sizes that will cover 90 to 95% of trail fixes. I thought it would be used to share in the forum.



For a Land Rover Discovery 2 (1999–2004), you'll find that most fasteners are metric, although a few imperial-sized wrench/socket heads occasionally appear on driveline and supplier-sourced components. Owners and technicians generally consider the D2 to be about 90% metric.



Most Common Socket & Wrench Sizes



If you're working on a Discovery 2, these are the sizes you'll use most often:



- Socket/Wrench Common Fastener

- 8 mm Hose clamps, trim brackets

- 10 mm M6 bolts, interior trim, engine accessories

- 13 mm M8 bolts, body brackets, engine bay components

- 15 mm Suspension and chassis hardware

- 17 mm M10 bolts, steering and suspension

- 19 mm M12 bolts, suspension, driveline

- 24 mm Axle, suspension, hub-related fasteners

- 27 mm Differential and axle work

- 30 mm Hub and driveline work



The most common metric thread sizes on the vehicle are M6, M8, M10, and M12. Typical hex-head sizes are: M6 = 10 mm, M8 = 13 mm, M10 = 17 mm, M12 = 19 mm.



Torx & E-Torx Sizes You'll Need



Land Rover loves Torx fasteners. A Discovery 2 tool kit should include:



- T20

- T25

- T30

- T40

- T45

- T50

- T55



And External Torx (E-Torx):



- E8

- E10

- E12

- E14



These are commonly found on:



- Seat mounts

- Engine accessories

- Transmission components

- ABS and braking hardware

- Steering column components

- Discovery 2 "Must-Have" Socket Set



For routine maintenance on your Discovery 2, I recommend:



Metric Sockets

- 8 mm

- 10 mm

- 13 mm

- 15 mm

- 17 mm

- 19 mm

- 24 mm

- 27 mm

- 30 mm



Torx

- T20–T55 set



E-Torx

- E8–E14 set



Other

- ½-inch breaker bar

- Torque wrench

- 36 mm fan clutch wrench (for many V8 cooling system jobs)

- 9/16-inch and 5/8-inch wrenches (occasionally useful on aftermarket or supplier-sourced components)

ü Fasteners You'll Encounter Most Often by Job



Jobs and Common Sizes

- Oil change 27 mm drain plug (some aftermarket plugs vary)

- Serpentine belt 15 mm tensioner

- Brake calipers 13 mm, 15 mm

- Driveshafts 9/16", 14 mm, 15 mm depending on shaft

- Suspension 18 mm, 19 mm, 24 mm

- Wheel nuts 27 mm

- Alternator 13 mm, 15 mm

- Water pump 10 mm, 13 mm

- Interior trim T20, T25, T30



For your 2003 Discovery 2, if you're putting together a trail or garage toolkit, a compact set containing 8, 10, 13, 15, 17, 19, 24, and 27 mm sockets plus T20–T55 and E8–E14 Torx sockets will handle roughly 90–95% of repairs you'll encounter on the vehicle.

 

This is very useful.