Braided Brake Lines

Braided stainless steel brake lines have become popular as an affordable standalone brake upgrade and are invariably included in off-the-shelf brake upgrade kits.

So what are the advantages of braided lines and what makes street-legal braided lines so special?

Braided Brake Lines – The Advantages

The most widely publicised advantage of braided stainless steel brake lines over conventional rubber hoses is reduced bulging when heavy brake force is applied. David Malkin of Maltech (one of Australia’s largest braided brake line manufacturers) says this results in improved brake response and pedal feel and can reduce stopping distances.

Unfortunately, we have yet to see any documented evidence to support these claims – so we asked Maltech to compare the distortion and bulging of rubber brake hoses and braided stainless hoses using their pressure test machine.

This out-of-car test involves installing the ends of each hose to a dedicated brake pressure test machine. The machine uses a mix of corrosion inhibitor and water to pressurise the inside of the hoses and, typically, the operator uses the machine to identify leaks. However, for our purposes, we used a pair of digital calipers to measure the outer diameter (OD) of the hoses in static and pressurised condition. The bigger the difference, the more the hose expands under pressure.

Note that these tests were conducted with the brake hoses pressurised to 3500 psi, which is considerably more than you’ll generate in a car – David says you might generate 1500 psi pressure in a hard brake application. This means the hoses will expand more in our tests than in a real-world application.

So how did the hoses compare?

Well, the first hose we tested was an old and worn rubber hose (which appears to be the original part from a ’65 Ford Mustang). In static conditions, this hose had an OD of 10.76mm and, when pressurised, it expanded to 11.02mm. An increase of 2.4 percent.

Next, we tested a brand new rubber hose. The new hose had a 10.47mm OD which expanded to 10.65mm when pressurised. An increase of 1.7 percent.

The final test was a new braided steel brake line. In static conditions, the braided line had an OD of 6.45mm and expanded to 6.49mm when pressurised. An increase of less than 1 percent.

So what can we conclude from this?

Well, yes, a braided steel brake line does give less expansion under pressure than a rubber hose - but the margin is extremely small. And keep in mind that these tests were conducted at more than double the pressure you might generate in a real-world situation. So the difference between braided steel and rubber brake hoses is extremely, extremely small...

The durability of braided brake lines is also difficult to judge. Street-legal versions of braided brake lines have existed for only around four years and, during this time, David says he’s never had any problems. If you’re looking for a bigger endorsement you should consider braided brake lines are standard fitment on the current FPV GT and GT-P.

David says traditional rubber brake hoses have an average recommended life of around six years - but on the other hand, he has also seen rubber brake hoses out-last the vehicle... Certainly, brake lines should be replaced if there is any visible cracking, blisters or fluid leaks.

Street-Legal Braided Brake Lines

So what is it that distinguishes street-legal braided brake lines from older style non-legal braided lines?

The key difference is the fitment of a specially formulated Teflon-based insert that slips around the braided line where it connects to the end-fitting. This insert prevents the braided line from tearing near the end-fitting while subjected to ADR whip testing. Non-legal braided brake lines typically use a rigid aluminium insert that cuts into the braided line during this testing.

All Maltech braided brake lines use a Brakequip-formulated insert that meets ADR 7/00 and 42/04 legal requirements. For use in counties outside Australia, we recommend checking local requirements.

The braided lines used by Maltech also feature a clear plastic sleeve which serves as protection. This sleeve is not an ADR legal requirement and can be removed if required for cosmetic reasons. This photo shows a sleeved braided line in the foreground and a bare braided line in the background.

Step-by-Step Assembly and Installation

We went along to Maltech’s workshop (based in Drysdale , Victoria) to watch the step-by-step construction and fitment of street-legal brake lines.

The demo vehicle was a Japanese-market Toyota Supra twin-turbo (JZA80 series). David already has the jig and measurements required to make braided lines to suit the Supra but, for the purpose of our exercise, he took us through the process of constructing new hoses from scratch. This photo shows one of Maltech’s brake line fabrication jigs – this particular jig is for the R32 Nissan Skyline.

When starting from scratch, the first step is to jack up the car and remove the relevant wheels. Next, the existing rubber brake lines are removed along with their associated brackets. Brake fluid is allowed to drain into a container.

This is the original Toyota Supra hose with its centre support bracket attached.

The centre support bracket is removed and the overall length of the hose is measured. The Supra hose is 440mm long. The same length of new hose is then cut from a reel of braided steel brake hose.

New end-fittings are used. The appropriate size and shape end-fittings are chosen and, if required, they may be bent slightly in a vice. The new end-fitting seen on the left has been bent to the necessary angle to suit the Supra.

The Teflon-based insert and end-fittings are now slid over each end of the hose. The end-fittings are lightly crimped using a pair of pliers to temporarily hold them in the correct orientation. David explains that the braided line doesn’t twist, which means the fittings must be correctly angled.

The end-fittings can now be hydraulically crimped. As seen here, the end-fitting is inserted into a crimping machine that crushes the fitting to a preset diameter. The braided line is crushed onto a small diameter passage inside the end-fittings.

This photo shows the end-fitting after it is hydraulically crimped.

In instances where the brake line requires a centre support bracket (like the Supra), a section of plastic sleeve is stripped from the braided line using a razor. A new support bracket and Teflon-based insert is then crimped onto the line using pliers. Extreme care must be taken to ensure the line is not crushed.

The new braided lines can now be pressure tested.

Both ends of the new braided lines are connected to Maltech’s pressure test machine. As described, the machine uses a combination of corrosion inhibiter and water to pressurise the lines to 3500 psi. The operator checks that there are no leaks, removes the lines from the machine and blows the water out using a compressed air gun. It’s extremely important that water is blown out of the lines before they are installed on a car.

Each braided line is then stamped with an ID number to confirm that all lines have been tested and can be traced back to Maltech.

Once tested and ID stamped, the new braided lines are fitted to the car using new crush washers and banjo bolts. The final step is to bleed the hydraulic system and top up the fluid.

Cost and Availability

Working from scratch, the whole process takes only around an hour for each pair of brake lines. The bill for the demo Supra (which includes fitment) comes to AUD$405 for the front and rear. Prices vary slightly depending on brake line length, the type of end-fitting and complexity but, as a guide, David says you’ll pay around AUD$100 per hose. In comparison, new rubber brake lines made by Maltech cost around AUD$35 each.

Maltech supplies AutoBahn and various other auto parts outlets with their street-legal braided line kits. Most popular vehicles are catered for and, if you can’t find lines to suit, Maltech can construct a set. Simply send them the original brake lines and brackets or, if you live in the Geelong area, you can call out Maltech for an on-site job.

The jury is still out on the advantages of braided steel lines but they might be worth a look if your existing brake hoses are looking tired.

Footnote: Unfortunately we were unable to make a driving comparison of new rubber brake hoses versus new braided brake hoses.

Contact:

Maltech
+61 3 5251 1790 / 0418 378 939

www.maltech.com.au