Description
Brass Bulkhead Brake Union M10 x 1mm with Lock Nut
Solid brass bulkhead brake union with an M10 x 1mm male thread at each end and a brass lock nut, for passing a 3/16″ (4.75mm) brake or clutch pipe through a panel, bracket or bulkhead. Popular on kit cars, race and rally cars. Supplied by EMS Spares, Leicester – over 30 years in automotive components.
Specification
| Thread | M10 x 1mm male both ends |
|---|---|
| Pipe size | 3/16″ (4.75mm) brake / clutch pipe |
| Type | Bulkhead union with lock nut |
| Supplied with | 1 brass lock nut per union |
| Overall length | N/A |
| Material / finish | Solid brass, natural finish – rust resistant, will not seize |
| Interchange reference | HU106* |
| EMS part number | EMS-A106 |
* 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: bulkhead brake unions explained
What does a bulkhead union do?
A bulkhead union takes a brake pipe through a panel or bracket and holds it firmly. The union passes through a hole and is clamped by its lock nut; each side then takes a pipe with a female union (EMS-A2A), whose flare seals on the end of the bulkhead union.
Step 1 – identify your thread (the most common mistake)
| Thread | Outside diameter (male part) | Threads | Typically found on |
|---|---|---|---|
| M10 x 1mm (this part) | 10mm approx | 1mm pitch (about 25 per inch) | 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) |
| 3/8″ x 24 UNF | 9.5mm approx | 24 per inch | Most British classics: MG, Triumph, Mini, Land Rover Series |
| M12 x 1mm | 12mm approx | 1mm pitch | Larger ports, some master cylinders and 1/4″ pipe |
Tip: M10 x 1 and 3/8″ UNF look almost the same and will start to screw together, then bind. M10 x 1 and M10 x 1.25 also look alike. Never force a fitting. Measure the male thread (10mm = M10, 9.5mm = 3/8″) and check the pitch with a thread gauge.
Step 2 – unions and nut
- Each end takes a female M10 x 1 union – see our EMS-A2A.
- Spare lock nuts: see our EMS-ALNB2 M10 x 1 half nut.
Step 3 – pipe size and flare
For 3/16″ (4.75mm) outside-diameter pipe, the standard UK car brake pipe size. Suits copper-nickel (Kunifer), copper and steel brake pipe. Match the flare on your pipe to the port it screws into – most metric ports take a DIN (inverted) or ISO bubble flare; if in doubt, copy the flare on your old pipe.
How to fit – good practice
- Drill the panel to suit the union body and remove any burrs.
- Fit the union through the panel and tighten the lock nut firmly.
- Start each female union by hand for several turns, then tighten while holding the bulkhead union with a second 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 1, 3 or 5 unions (each with a lock nut). 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.
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FAQ
Will this fit copper (Kunifer) pipe? Yes – any 3/16″ (4.75mm) brake pipe: copper-nickel, copper or steel.
Is M10 x 1 the same as 3/8″ UNF? No. They are close in size (10mm against 9.5mm) but the threads are different and will bind. They are not interchangeable.
Why brass and not steel? Brass does not rust or seize, so fittings can be undone again years later.
Is the lock nut included? Yes – one brass lock nut with every union.
Need help? Message us with your vehicle and the part you are connecting to and we will confirm the right fitting before you order.
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