TECH: BRAIDED HOSES
Braided hoses and uprated fittings are excellent replacement parts for ageing rubber pipework prone to failure…
Braided hoses are excellent replacement parts for ageing rubber pipework prone to failure.
Big brake conversions, increased engine fuelling demands and highperformance transmission upgrades are just a few features of modified motors which push the limits of standard specification rubber fluid transfer hoses and their accompanying factory fittings. The solution is to fit steel braided hoses, perhaps adding Airforce Navy (AN) fixings for good measure. Not only will braided lines withstand higher pressures, they’ll dissipate heat far more effectively. They’ll also allow for strong hose ends to be fitted, removed and refitted several times without risk of fraying, damaging or weakening of parts. They look great too. Improved function and enhanced form? What’s not to love?!
Two basic braided hose types exist. The primary type is rubber (or synthetic rubber) tube with an inner half-braid covering matched with a full-braid outer stainless steel layer. This type of hose has a working temperature range of between -50°C and +150°C and is well suited to fuel, oil and cooling systems where lightweight materials, flexibility, increased resistance to heat and sure-fire durability is required.
The second type of braided hose is a Teflon tube with a single-braid outer cover. The working temperature of this type of hose is between -73°C and +232°C. It’s a far more aggressive type of hose, ideal for braking systems and where unusually high pressure fuel, oil and cooling applications are present, such as motorsport environments.
Using either of these two options as your starting point, you might be tempted by twin-layer synthetic hoses with a half-braid sandwiched between each layer. There’s also the option of ultra-strong, super-light, Kevlar-braided hoses for serious motorsport applications and
Performance Vauxhall readers who intend to build a custom four-wheeler to assist their crimefighting activities in Gotham. Or something.
AN fixings are supplied with either male or female ends in a wide variety of sizes to suit your chosen application. As you’d expect, the ends screw together to complete a joint. Ordinarily, the male end is fixed to the car’s supporting component (e.g. fuel tank, turbocharger housing or oil reservoir), but in the case of braking systems, the male end of the hose fitting takes the form of a banjo union with a threaded fixing.
A key advantage of AN fittings is that unions can be straight, angled or even able to turn a hose 180° to allow the plumbing of bespoke pipework in the tightest of areas. Adaptor unions can also be used on an AN system. Utilising these parts gives you the flexibility of adding extra angles to the hose line, and you could even use them to increase or decrease hose bore to suit your requirements. Additionally, AN unions will allow you to split a single line into multiple lines via T or Y-piece sections.
Most braided hose manufacturers supply readymade kits (e.g. braided brake hose solutions) for various makes and models of car. If your pride and joy happens to be a bit rarer than the rest, then fluid transfer hose manufacturers, including HEL, Goodridge, Speedflow and Hosetechnik, will be happy to make a bespoke kit for you. If you’re feeling adventurous, you can measure the length of hose required, work out the AN fixing dimension needed and make your own kit. The boxout to the right shows you how to do it.
outer weave of stainless steel braid. nipple inserts into the hose.
The mechanical fixing of the hose occurs when the stainless steel braid is trapped under the socket nut. The stepped internal face grabs and holds the braid. Cutter cuts into the hose. Internal Viton o-ring seals the nipple insert on this straight hose end. Most angled hose ends are a single piece from seat to nipple insert.