BRAKE FLUID

How regularly should you change your brake fluid

In Summary

• The brake fluid on the other hand, in its natural state, is believed to be hygroscopic. 

• Once moisture or water gets into the braking system, the brake fluid becomes compressible. 

Once moisture or water gets into the braking system, the brake fluid becomes compressible.
Once moisture or water gets into the braking system, the brake fluid becomes compressible.
Image: BOOSTED AUTO

The braking system is arguably the most essential part of an automobile. You may have a car with everything technology could give but lack of effective brakes would jeopardise your driving experience and cause death

 A bigger percentage of the automotive world utilises a hydraulic braking system of which brake fluid is the main media of force transfer from the driver's foot to the brake pads/linings. 

Any foreign matter in the braking system compromises its efficiency thus greater care must be observed to keep the brakes in proper working condition. This foreign matter includes air, water, dust, rust etc. One of the qualities which make brake fluid the first choice in a braking system is because it is incompressible. Braking force is needed to be 

transferred from the driver's foot at an instant to the road wheels. Its ability to be incomprehensible ensures quick reaction speed whenever the driver desires to do so.

 The brake fluid on the other hand, in its natural state, is believed to be hygroscopic, meaning it can absorb moisture/water from the atmosphere up to  3.5 per cent of its weight every year. 

Once moisture or water gets into the braking system, the brake fluid becomes compressible. Something which works contrary to its initial intended purpose of being incompressible. 

  Moisture may find itself inside the braking system in several ways but the main ones are in three categories 

  • Improper sealing.

Brake reservoirs must be tightly sealed to repel off any external matter. If not well sealed or if left open, can cause moisture, rainwater or water from car wash to sip through into the braking system.

  • Overheating. 

Using a none specified brake fluid or applying hard brakes while driving can cause the brake shoes to overheat. Through the conduction of heat, the brake shoes transfer heat unto the brake fluid causing it to boil. We all know that water is a by-product of boiling. Eventually, when cooling later takes place it leaves the braking system with water traces.

  • Usage of old brake fluid top-up up.

Most car owners make this mistake unknowingly. As discussed earlier we learned that brake fluid is hygroscopic. 

Once the brake fluid has been opened it should be used at once. The remnants should not be carried inside our cars. If it must be carried then it should only be used for emergencies which calls for a full brake fluid flash once you are safe and settled. 

 Other than the usual cap on the brake fluid container, there is a special formulated tamper-proof seal. Its main purpose is to restrict moisture from outside getting into the container. When the tamper-proof seal has been opened, the shelf life of the brake fluid is compromised instantly.

Once water gets into the system, apart from making the system compressible, it also corrodes the brake pipes and brake pistons. The corrosion reacts with the seals and causes the brake fluid to turn blackish. If not looked into on time the aftermath is leaking brake pistons and brake failure. So this brings us to our big question.

HOW OFTEN SHOULD YOU FLUSH IT

Brake fluid regular checks are advised.

Top up with manufacture recommended specifications if need be. Brake fluid must remain clean at all times. Any blackish substance observed in the system indicates foreign matter in the system. This calls for immediate brake fluid flush without thinking twice. However, if your brake fluid is still clean, flushing it in every 45000km to 55000km or every 2 years is recommended depending on which one comes first. During the flushing process, all the old brake fluid must be flushed out until signs of newly fresh fluid is observed at the brake nipples. Start with the furthest brakes from the brake master cylinder to the nearest in that order.  By all means, ensure the brake fluid does not get on the vehicle paint or else it will corrode it. 

Gently bleed the air after refill. If the car is a manual transmission, always flush the clutch system during brake flushing to avoid any eventualities in future. 

The writer is the owner of Boosted Auto repair shop