Molykote Specialty Lubricants Help Ensure Performance of Brake System Components

12/01/2008 - Molykote Specialty Lubricants Help Ensure Performance of Brake System Components

To maintain the safety, comfort and value of increasingly sophisticated automotive braking systems, selecting the right lubricant is one of the most challenging tasks for brake system designers and engineers.

Specialty lubricants have particular properties and characteristics for use in situations where stresses occur that are beyond the capacity of conventional lubricants, such as high pressure, extreme high and low temperatures, vibration, shock loads, start-up and run-down phases, sliding surfaces heavily loaded during running-in and aggressive environments.

Specialty lubricants for brake systems include:

Greases -- thick or semi-fluid dispersions of a thickening agent in a lubricating liquid.
Pastes -- high concentrations of solid lubricants dispersed in oil for convenient application.
Friction control additives-- solid substances that are applied in sliding surfaces to reduce friction and wear and prevent scoring
Anti-friction coatings -- paint-like products that contain submicron sized particles of solid lubricants instead of coloring pigment, dispersed through carefully selected resin blends and solvents

Their applications include:
Pedal systems - New designs use polymeric composites of glass-fiber-reinforced thermoplastics take lead to different requirements for the lubrication of the pedal joint. The required plastic compatibility can be achieved by silicone- or polyolefin-based greases. Silicone based greases show very good dampening and anti-vibration properties due to excellent low temperature behavior and high viscosities availability.

Brake boosters – Greases are the best choice to provide good lubricity at low temperatures as low as -40°C, and to be compatible with a wide range of different plastics and rubbers, especially in guide pin-, sliding boot-, reaction disc-, plunger- and vacuum seals.

Brake Calipers - The common types of automotive brake systems are based on the caliper disc brake. At the brake caliper, several areas which need to be lubricated to provide trouble-free movement of the sliding parts and to avoid or reduce noises and vibration.

Brake caliper guide pin -- In general a solid-containing lubricant with a good lubricity and load carry capacity over a wide temperature range is needed. Silicone and PAG based greases are both suitable because of their low temperature and good rubber compatibility.
Brake pad shim – Greases and pastes are appropriate for their good lubricity, wide temperature range, and good dampening capacity and vibration absorption.
Brake pad guiding spring -- A “dry” anti-friction coating lubricant with insulating and corrosion preventing properties needs to be applied to the steel spring to provide the accurate lubrication of the brake pad in the caliper sliding guides and act as insulating and anti-corrosion coating.

Brake pads - In general a friction brake converts velocity into heat through friction. The brake components (pad/disc or lining/drum) are in sliding contact, which can be controlled by lubricants (friction control additives) which will not reduce friction, but should stabilize friction at a controlled level.

Conclusion
From the brake pedal to the brake pad, specialty lubricants satisfy a number of criteria, including the ability to operate in low and high temperatures, variable speeds and loads, and exposure to water and dust; offer good compatibility with rubbers, corrosion protection, noise reduction, dampening, sealing, and insulating properties; and be non-toxic, environmentally friendly, and fulfill all international regulatory requirements.

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