251321 - Lock Nut – 5/16" BSF

- €1,80

€1,80

€1,80 - €1,80

€1,80

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Aftermarket: Quality alternative. This is a quality alternative, designed to fit and function like the original part, often at a more competitive price.

Lock Nut with a 5/16" BSF thread.

The lock nut secures a threaded fastening against loosening under vibration, maintaining clamp load in service. Used on the 2.0L 4-cylinder petrol engine.

Vehicle Model Land Rover Defender up to 2016
Land Rover Series 2 and 3

Fitment Notes SERIES II 1958-1961 — 2.0 Petrol engine

Alternative Codes

25132150525BR 1173

In stock 24 units

14 · Gouda 10 · Drachten

Express delivery available

When will my order arrive?

Order before 15:00 (Mon–Fri): same-day dispatch for in-stock items.
UPS Express (order before 14:00): dispatched today, delivered tomorrow where available.
Netherlands / Belgium / Germany: 2–4 working days.
Other EU countries + UK: 4–8 working days.
Outside EU/UK: delivery times vary — contact us for an estimate.

Items may ship from multiple warehouses at no extra cost.

Job kits containing this part

This part is included in 0 job kit(s) below. Pick the kit that matches your vehicle and job, then add what you need.

Frequently asked questions

What is the 5/16 inch BSF lock nut used for?

The 5/16 inch BSF lock nut secures a threaded fastening against vibration so it holds its clamp load in service. The BSF (British Standard Fine) thread suits the older imperial fixings on the 2.0L 4-cylinder petrol engine. It's a general-purpose locking nut for that thread size.

What does BSF mean and will it fit a metric or UNF thread?

BSF means British Standard Fine, an imperial thread used on early Land Rovers. This 5/16 inch BSF lock nut only fits a matching 5/16 inch BSF stud or bolt, not a metric or UNF thread of similar size. Match the thread standard, not just the diameter, before fitting.

Can the lock nut be reused?

It's best to replace the lock nut rather than reuse it. A locking nut's grip typically weakens each time it's wound on and off, so a reused one may not hold as well against vibration. Fitting a fresh 5/16 inch BSF nut keeps the joint secure under load.