Practical Automotive Maintenance: Brake Lines
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Brake Lines
03.37
| 00:00 | Braking systems rely on a combination of hard lines and soft lines to transmit hydraulic pressure from the master cylinder to the brake components, making their integrity crucial for vehicle safety. |
| 00:11 | Brake lines fall into two categories, solid and flexible. |
| 00:15 | The solid lines are used to link different parts of the braking system together when no movement is required. |
| 00:21 | As such, they're normally made from steel tube that's bent to follow the contours of the chassis or bodywork. |
| 00:27 | Hard lines are essentially completely rigid, meaning they don't expand under the hydraulic pressure seen in our brake system. |
| 00:34 | This minimizes compliance in the brake system that can result in excessive pedal travel. |
| 00:38 | This is why OE manufacturers use hard lines when brake fluid has to travel a long distance, such as from the master cylinder to the rear calipers. |
| 00:47 | With hard lines covered, let's now move on to flexible brake hoses. |
| 00:50 | This is used at specific points in the braking system to accommodate the components that move and require a degree of flexibility. |
| 00:58 | An example of this is the suspension as it moves through its full range of travel or on the front axle as we move the steering. |
| 01:05 | Hard lines can't accommodate this movement, which is why flexible lines are used at this point, allowing articulation of the suspension and steering components while reliably transferring hydraulic pressure to the brake calipers. |
| 01:17 | Standard rubber brake hoses typically consist of multiple layers. |
| 01:21 | An inner rubber layer containing the brake fluid, a middle layer of textile reinforcement for strength and an outer rubber layer for environmental protection. |
| 01:31 | Used in most OEM applications, rubber brake hoses do an acceptable job. |
| 01:36 | However, they do have a finite lifespan, typically requiring replacement every 5 to 10 years as they age and deteriorate. |
| 01:43 | Although this time frame does depend on vehicle use and environmental conditions. |
| 01:48 | When rubber lines begin to deteriorate, we'll be able to see visible cracks appear on the outer layer, indicating oxidation of the material. |
| 01:55 | This can lead to brake line swelling and eventually complete failure. |
| 01:59 | Finally, one of the biggest issues with rubber brake hoses, especially in motorsport, is their tendency to expand under pressure, resulting in excessive pedal travel and this is where stainless steel braided flexible hoses come in. |
| 02:12 | As the name suggests, these lines use a tightly woven stainless wire in the place of a textile reinforcement to form a stronger, more expansion resistant line, while remaining flexible to allow for articulation of our suspension and steering components. |
| 02:26 | Instead, of a rubber inner structure, the style of brake line incorporates an inner tube made from PTFE, aka Teflon, which also increases the expansion resistance to help with the consistent brake force application and pedal feel. |
| 02:39 | Another benefit of the stainless steel braid is the excellent resistance to the elements and oxidation, making it last longer in harsh environments. |
| 02:48 | One last thing to consider, regardless of the material used, is that the routing of the brake lines should be done in a manner that prevents them from making contact with other components that could potentially damage them. |
| 02:58 | Let's cover the key points in this module before moving on. |
| 03:02 | Automotive brake lines and hoses form a vital link between driver input and stopping power, with different materials offering specific pros and cons depending on the application. |
| 03:12 | Hard lines create a durable, rigid solution for brake fluid transfer, while flexible hoses, either rubber or stainless braided, allow for suspension and steering movement. |
| 03:21 | Most OEMs use rubber lines for flexibility, though they can expand under extreme conditions, adding compliance. |
| 03:28 | Braided stainless steel hoses resist expansion, offering improved performance and more consistent brake feel. |
