Description
Stainless Steel Brake Pipe Union 7/16″ UNF x 20 Male for 1/4″ Pipe
Stainless steel male brake pipe union with a 7/16″ x 20 UNF thread, for 1/4″ (6.35mm) brake and clutch pipe. Screws into 7/16″ UNF female ports such as master cylinders and larger valves. Supplied by EMS Spares, Leicester – over 30 years in automotive components.
Specification
| Thread | 7/16″ x 20 UNF male |
|---|---|
| Pipe size | 1/4″ (6.35mm) |
| Type | Male union |
| Hex / spanner size | 12.7mm A/F approx |
| Overall length | 21.3mm approx |
| Material / finish | Stainless steel, natural bright finish – rust resistant |
| Interchange reference | HU14* (brass equivalent) |
| EMS part number | EMS-A14SS |
* 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: stainless brake pipe unions explained
Why stainless steel?
Stainless steel fittings resist rust and road salt, keep a clean bright finish and are harder than brass, so the hex is less likely to round off. They are popular on restorations, show cars, kit cars and vehicles used all year round. Brass is softer and seals very easily; stainless is tougher and longer-lasting – both work with copper-nickel (Kunifer), copper and steel brake pipe.
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 |
| 7/16″ x 20 UNF (this part) | 11.1mm approx | 20 per inch | Larger British ports, some master cylinders and 1/4″ pipe |
| M10 x 1mm | 10mm approx | 1mm pitch | Most European and Japanese cars, many later British cars and kit cars |
| M10 x 1.25mm | 10mm approx | 1.25mm pitch | Some older Italian and French cars (e.g. Fiat, Lancia) |
| M12 x 1mm | 12mm approx | 1mm pitch | Larger metric ports and 1/4″ pipe |
Tip: 3/8″ UNF and M10 x 1 look almost the same and will start to screw together, then bind. Never force a fitting. Measure the male thread and check the pitch with a thread gauge.
Step 2 – male or female?
- Male union: screws into a female port (this part)
- Female union for 1/4″ pipe – see our EMS-A4ASS.
Step 3 – pipe size and material
For 1/4″ (6.35mm) outside-diameter pipe – larger brake and clutch lines. Suits copper-nickel (Kunifer), copper and steel 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 1/2″ (12.7mm) split / flare nut spanner, not an open-ended spanner. Stainless is hard – tighten firmly but do not over-tighten.
- 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 or 5 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 stainless fit my existing brass fittings? Yes – the thread and seat are the same, so a stainless union screws into the same port as a brass one.
Will it rust? Stainless steel resists rust and road salt and keeps its bright finish.
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.