Description
Steel Brake Pipe Union 3/8″ BSF x 20 Male for 3/16″ Pipe
Steel male brake pipe union with a 3/8″ x 20 BSF thread, for 3/16″ (4.75mm) brake and clutch pipe – for older British classics with BSF fittings. Supplied by EMS Spares, Leicester – over 30 years in automotive components.
Specification
| Thread | 3/8″ x 20 BSF male |
|---|---|
| Pipe size | 3/16″ (4.75mm) |
| Type | Male union |
| Hex / spanner size | N/A |
| Overall length | N/A |
| Material / finish | Steel, plated finish |
| Interchange reference | HU3* (brass equivalent) |
| EMS part number | EMS-A3S |
* Reference numbers are for identification and cross-reference only. EMS Spares is an independent UK supplier and has no connection with the owners of these part numbers. All dimensions are approximate.
Buyer’s guide: steel brake and fuel pipe unions explained
Why steel?
Steel fittings are strong, hard-wearing and low cost, and match the original-equipment style on many fuel and brake lines. A plated finish helps resist corrosion. For a part that will never seize, see our brass or stainless steel versions.
What does a brake pipe union do?
A brake pipe union is the threaded nut that holds a flared brake pipe tight against a component or hose. The union itself does not seal; it clamps the flare on the end of the pipe against the seat of the mating part, and that metal-to-metal contact makes the seal. That is why the thread and the flare type must both match.
Step 1 – identify your thread (the most common mistake)
| Thread | Outside diameter (male part) | Threads | Typically found on |
|---|---|---|---|
| 3/8″ x 24 UNF | 9.5mm approx | 24 per inch | Most British classics: MG, Triumph, Mini, Land Rover Series, Jaguar, kit cars |
| 3/8″ x 20 BSF (this part) | 9.5mm approx | 20 per inch | Older British cars, often pre-1960s (Morris Minor, early MG, Austin) |
| 7/16″ x 20 UNF | 11.1mm approx | 20 per inch | Larger British ports, some master cylinders and 1/4″ pipe |
| 1/2″ x 20 UNF | 12.7mm approx | 20 per inch | Fuel lines, carburettors and larger brake ports (5/16″ or 1/4″ pipe) |
| M10 x 1mm | 10mm approx | 1mm pitch | Most European and Japanese cars, kit cars |
Tip: 3/8″ BSF and 3/8″ UNF have the same diameter but different threads (20 against 24 per inch) and will not fit each other. Count the threads over one inch or use a thread gauge. Never force a fitting.
Step 2 – male or female?
- Male union: screws into a female port (this part)
- Brass version – see our EMS-A3.
Step 3 – pipe size and material
For 3/16″ (4.75mm) outside-diameter pipe, the standard UK car brake pipe size. Suits copper-nickel (Kunifer), copper and steel brake pipe.
How to fit – good practice
- Slide the union onto the pipe the right way round before you make the flare.
- Make the flare with a proper flaring tool, matching the flare of your old pipe and the port it connects to.
- Start the union by hand for several turns – it should turn freely. If it binds, stop and check the thread.
- Tighten with a suitable split / flare nut spanner, not an open-ended spanner.
- Bleed the brakes, then check every joint for leaks with the pedal pressed hard.
Safety: brakes are a safety-critical system. If you are not confident, have the work done or checked by a qualified mechanic.
Pack sizes
Available as 5 or 10 unions. Larger packs cost less per piece.
Delivery
Free UK delivery on every order (including Northern Ireland, Highlands & Islands). Same-day dispatch on orders placed before 10am.
Trusted by thousands of buyers on eBay
99.9% positive feedback from over 9,700 ratings, and 5.0 out of 5 for accurate description, postage cost, delivery time and communication (last 12 months). Read our eBay feedback.
FAQ
Will this fit copper (Kunifer) pipe? Yes – any pipe of the stated size: copper-nickel, copper or steel.
Brass or steel? Steel is strong and low cost; brass (EMS-A3) will not rust or seize.
Need help? Message us with your vehicle and the part you are connecting to and we will confirm the right fitting before you order.
Reviews
There are no reviews yet.