Installing Braided Stainless Steel Brake Lines
By John Gunnell
They are called braided stainless steel brake lines or braided stainless steel brake hoses. Whatever you call them, they are flexible hoses designed to take the place of conventional rubber hoses in a hydraulic brake system.
Braided stainless steel brake lines were developed to improve brake system performance and effectiveness. They will also last much longer than flexible rubber hoses because they eliminate the brake hose expansion that affected rubber brake hoses.
Differences in the way that rubber hoses and braided stainless steel hoses are constructed accounts for their different expansion characteristics. Conventional brake hoses usually have a rubber inner hose wrapped in a braided fabric reinforcement braid. On top of this is an additional layer of outer sheathing that is also made of rubber.
Braided stainless steel hoses typically feature a generic polytetrafluoroethylene or Teflon inner hose wrapped in braided stainless steel wire. The stainless wire braid is what increases resistance to expansion from the pressure that builds up inside the inner hose. This improves the performance of the brake system because there's a more direct transfer of the driver's braking actions to the friction surfaces at the wheels that stop the vehicle.
Usually — but not always — the stainless steel braiding is coated or covered with a clear or colored material (such as polyvinyl chloride or PVC) to protect the wire and inner hose from the elements and chemicals and to help minimize abrasion. The coating also gives a better appearance.
Coated braided stainless steel hoses have the same basic make up as conventional rubber hoses in the sense that you have a rubber inner hose wrapped in a braid followed by an outer layer, but the stainless steel hoses provide substantially different — and most say better — braking performance.
For any user of stainless steel brake hoses, higher cost is required to purchase a set of hoses. They will generally cost from two-and-a-half to three times as much as conventional rubber hoses. Do, safety and better braking comes with a cost. Our set of three hoses cost just under $100 with shipping. For car collectors, a non-original appearance might be considered another drawback. If your car is going to be judged for originality, those shiny, thin braided stainless steel hoses are going to cost you points.
Braided stainless steel hoses are considerably thinner than conventional rubber hoses. This is because the outer layer of thick rubber used to protect regular hoses from road damage is no longer required. The thinness of the braided stainless steel hoses should not worry you, but it is a good idea to check that they are about the same length as the original hoses you're replacing. That way you know they are long enough for the application and will work without getting tangled on some suspension part when you turn the steering wheel.
The design of the new hoses may not exactly match the design of the old hoses. This is probably because the parts manufacturer isn't designing new parts for old cars. Someone has simply figured out the proper length hose to replace the hoses on your old car. But the new hoses may have differences such as a shorter or longer threaded nipple on one or both ends. The hoses we purchased from TSI Automotive were for a Triumph TR8. The original rubber hoses had one nipple that was shorter than the other, while the braided stainless steel hoses had the same length nipples on both end. The overall lengths were the same.
The installation of the new brake hoses was very straight forward and simple on the Triumph TR8, especially since we had all of the brake and many of the suspension parts already removed from the car. However, the old brake hoses were still on both sides of the car. We decided to do one side at a time, so the other could be used as a model to show us where each fitting goes. That way we knew that both sides would be put together properly.
Car hadn't been driven in years so it seemed like a good idea to replace the old rubber hose. Caliper end piece is tucked up to prevent brake fluid drips.
The TR7/TR8 braided stainless steel brake hoses kit came in plastic bag from TSI Automotive (www.tsimportedautomotive.com).
Here are our three braided stainless steel hoses. The two shorter ones are for the front brakes. Longer hose is for the rear of the car.
The first thing we did is lay out the three new brake hoses. Two of them were the same size and one was longer. We wanted to absolutely verify that the two slightly shorter hoses were for each side up front. This was the logical case, but over the years we have seen cars with some pretty weird things. A peek in the Victoria British catalog for TR7/TR8 parts confirmed that the TR8 takes three brake hoses and that the front two have the same part number. This told us that the front brake hoses for this car are definitely the same length.
We peeked in a Victoria British parts catalog to double check that both front brake hoses were the same size. They were the same part number.
The lengths of the new hoses should closely match the length of the hoses on the car. As you can see, this was the case with the hoses we ordered.
Once you can move the old nut up the brake line, you can separate the brake line from the threaded nipple type brake hose connection.
After checking that the length of the two hoses was the same and that their lengths matched those of the old rubber hoses, we began to remove the hoses by undoing the connection. This required two wrenches, one to turn the nut that attaches the hoses to the brake lines and one to keep the nut on the hoses stationary. Since brake line fittings and hose fittings are made of relatively soft metal, they can be easily ruined by a regular open-end wrench — a six-point brake line wrench (also known as a flare wrench) is recommended. You can get a pretty good set of these at Harbor Freight or Northern Tool for a very reasonable price.
Always use a six-point flare wrench to loosen an/or tighten the hose and line connections. Various sizes are required for different nuts.
The ends of the six-point flare wrenches slide over the brake line and onto the huts, giving a firm grip that won't tear up the soft metal nuts.
Once the nuts that attach the brake hoses to the brake lines are completely loosened, they can be slid up the line so the hose-to-line connection can be broken. On our particular project, the brake lines had been undercoated and the protective black covering kept the nut from sliding upwards. We used a razor blade to scrape the undercoating off. We'll protect the lines against rust using another product called Rust Prevention Magic that we've written about before on this Website.
We used a razor blade to clean up the short brake line because it had too much old undercoating on It. The nut could not be slid upwards for clearance.
We removed the old rubber hose on the passenger side of the car with the short brake line that runs to the front brake caliper still attached. There were star washers around the brake hose nipples and we wanted to make certain that we knew the order in which the parts are to be assembled. By leaving the driver's side brake hose connected, we had a model to guide us. We could have also made drawings or taken digital photos or referenced the factory parts manual that has coloring-book-like illustrations of all TR7/TR8 parts and how they go together.
Top to bottom are the short line that runs to the brake caliper, the old rubber brake hose and the new braided stainless steel brake hose.
Once we had all the parts removed, we wire brushed all of the fittings until they were shining. We also wire brushed the short brake pipe that goes to the caliper. These parts also got the Rust Prevention Magic treatment. Then we put everything back together using the new braided stainless steel brake hoses. The end result is a nice-looking brake hose system that won't rust.
With re-useable pieces cleaned up, here's how the front brake line and hose looked. Connections will be tightened fully when end pieces are positioned.
Advantages of Braided Stainless Steel Brake Hoses:
Pedal feels firmer upon application.
Braking response to pedal pressure is quicker.
More precise brake modulation.
Non-hydroscopic' resists moisture.
Shorter stopping distance due to shorter reaction time.
High pressure (up to 4500 PSI) testing.
Disadvantages of Braided Stainless Steel Brake Hoses
- Non-original look.