Brake hoses and brake lines
Here you will find useful information and important tips relating to the brake line, brake hose, and hand-brake cable in vehicles.
Important safety note
In hydraulic brake systems, brake hoses and brake lines are used to transfer brake fluid. Brake lines connect the actuation device such as the brake master cylinder to the hydraulic components of the wheel brake. Brake hoses are used as flexible connecting pipes in all moving areas between the body and chassis.
With the integration of ABS, ESP, and TCS systems in modern vehicles, the operative requirements placed on these assemblies have risen dramatically. Included among the main requirements are compressive strength, mechanical load-carrying capacity, and thermal and chemical resistance.
Brake hoses comprise a special rubber mixture and integrated braiding that considerably improves the strength of the hose and serves as a pressure support.
As a result of these influences, brake hoses and brake lines need exceptional pulse strength, robust connecting elements, and high fatigue strength.
The minimum requirements for marking, performance, mounting, and connections of brake hoses for vehicles are defined in the SAE J 1401, FMVSS 571.106, and ISO8 3996 norms.
Not only do the lines need to specify the manufacturer, but also the corresponding specification on the sleeve. A colored label or a label stamped or pressed into the material displaying axial rotation should also be present on the hose. A white longitudinal line extending across the length of the hose is typically provided. When a replacement is carried out, only brake hoses that correspond to this norm should therefore be used.
Hella Pagid brake hoses surpass all SAEJ1401 specifications to ensure that we live up to our claim of providing the very highest levels of quality and safety.
Brake lines and brake hoses are safety-relevant components and should be checked every time the vehicle is maintained. Typical defects include corrosion on the brake lines and damage to the hoses.
These defects can be caused by accidents, improper assembly, or aging. By carrying out a visual inspection, it is usually possible to detect chafing, cracks, bubble formation, corrosion, and other external damage with minimal outlay.
The following points should be taken into account by the technician when carrying out a repair:
Improper installation can negatively impact the driving characteristics of the vehicle and endanger lives.
As required by law, multi-track vehicles must have two brake systems that operate independently from each other. A parking brake system is also required in addition to the service brake system. The parking brake, also called a hand-brake, is designed to prevent a vehicle that has come to a stop or has been parked from rolling away. When the mechanical hand-brake is actuated by pulling on the hand-brake lever, brake force is transferred via cables to the wheel brakes of the rear axle.
The hand-brake cables are steel cables (Figure 1) that are routed in tubes or metal hoses – also called Bowden cables. The brake cables are adjusted using additionally installed adjustment devices. To protect against the effects of weather such as water and dirt, Bowden cables are sheathed in plastic.
There are two main types of steel cable installed in hand-brake cable systems (Figure 2). Only tested, high-quality materials are used to manufacture HELLA PAGID hand-brake cables. The steel cable used – with its special properties with respect to robustness and flexibility – is also always chosen in direct relation to the vehicle and brake system fitted.
As a result of these influences, brake cables need exceptional tensile strength, robust sleeves, high-quality connecting elements, and high fatigue strength. A defective hand-brake cable is only noticeable when the parking brake fails.
Hand-brake cables can only be correctly adjusted if all components of the hand-brake system are fully functional. By carrying out a visual inspection, it is usually possible to detect chafing, cracks, corrosion, and other external damage with minimal outlay. Check exposed wire cables for breakage or splitting and replace if necessary. Check deflection rollers and guides for ease of movement and proper operation.
Basic adjustment of the parking brake should be carried out when:
The repair notes issued by the respective vehicle manufacturers must be observed in this context.
The following points should be taken into account by the technician when carrying out a repair