Description
Brass Brake Pipe Union 3/8″ UNF x 24 Male Short (No Lead) for 3/16″ Pipe
Solid brass male brake pipe union (male tube nut) with a 3/8″ x 24 UNF thread, made for 3/16″ (4.75mm) brake and clutch pipe. This is the short, no-lead version – no plain pilot section on the front – for shallow ports where the standard long union (EMS-A1) bottoms out before the flare is clamped. Supplied by EMS Spares, Leicester – over 30 years in automotive components.
Specification
| Thread | 3/8″ x 24 UNF (24 threads per inch) |
|---|---|
| Pipe size | 3/16″ (4.75mm) brake / clutch pipe |
| Type | Male union, short, no lead (no pilot) |
| Overall length | 17-18mm approx |
| Hex / spanner size | 11mm approx |
| Flare type | N/A |
| Material / finish | Solid brass, natural finish – rust resistant, will not seize |
| Weight | 7.6g approx each |
| Interchange reference | HU1B* |
| EMS part number | EMS-A1B |
* 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: long or short brake union?
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 – master cylinder, wheel cylinder, T-piece or valve. The union itself does not seal; it clamps the flare on the end of the pipe into the seat of the port, and that metal-to-metal contact makes the seal.
Step 1 – identify your thread
| Thread | Outside diameter (male thread) | Threads | Typically found on |
|---|---|---|---|
| 3/8″ x 24 UNF (this part) | 9.5mm approx | 24 per inch | Most British classics: MG, Triumph, Mini, Austin, Morris, Land Rover Series, Jaguar, kit cars |
| 3/8″ x 20 BSF | 9.5mm approx | 20 per inch | Older British cars (often pre-1960s) |
| M10 x 1mm | 10mm approx | 1mm pitch (about 25 per inch) | Most European and later cars |
| 7/16″ x 20 UNF | 11.1mm approx | 20 per inch | British classics and commercial vehicles, often on 1/4″ pipe circuits and master cylinders |
Tip: 3/8″ UNF and M10 x 1 look almost the same and will start to screw in, then bind. Never force a fitting – forcing the wrong thread damages the port. Measure the male thread diameter or use a thread gauge, or compare against your old part.
Step 2 – long (with lead) or short (no lead)?
- Long with pilot lead (EMS-A1): the most common type. The plain lead guides the union in straight and supports the pipe.
- Short, no lead (this part, EMS-A1B): for shallow or compact ports, some T-pieces, valves and older cylinders where a long union would bottom out before it clamps the flare.
- How to check: compare with your old union, or measure how deep the thread goes in the port. If the old union had no plain section at the front, choose this one.
Step 3 – male or female?
This is a male union – thread on the outside – that screws into a threaded hole. For a male port (for example many flexible hoses) choose a female union such as EMS-A1A.
Step 4 – pipe size and material
For 3/16″ (4.75mm) 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 component.
- Start the union by hand for several turns – it should turn freely. If it binds, stop and check the thread.
- Tighten with an 11mm split (flare nut) spanner, not an open-ended spanner. Brass is softer than steel – firm, not excessive.
- 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 1, 3, 5 or 10 unions. Larger packs cost less per union.
Delivery
Free UK delivery on every order (including Northern Ireland, Highlands & Islands). Same-day dispatch on orders placed before 10am.
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FAQ
What is the difference between EMS-A1 and EMS-A1B? Same thread and pipe size. A1 is the long union with a pilot lead; A1B is short with no lead, for shallow ports.
Which spanner do I need? An 11mm split (flare nut) spanner.
Will this fit copper (Kunifer) pipe? Yes – any 3/16″ (4.75mm) brake pipe.
Need help? Message us with your vehicle and the part you are connecting to and we will confirm the right union before you order.
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