ACCURATE BRAKE FLUID TESTING
The most popular product AutoTest demonstrated at AAAE was its Brake Fluid Tester
Most brake fluids used today are glycol-ether based. Glycol-ether (DOT 3, 4 and 5) brake fluids are hygroscopic, which means they absorb moisture from the atmosphere.
Glycol-based brake fluid starts to absorb moisture from the moment it is put in the hydraulic brake system or exposed to the air.
The fluid attracts moisture through microscopic pores in rubber hoses, past seals and exposure to the air. The problem is obviously worse in wet climates where humidity is high.
Brake fluids must maintain a low level of compressibility. This is important to ensure consistent brake-pedal feel.
As compressibility increases, more brake-pedal travel is necessary for the same amount of brake force and the brake pedal will feel different.
The brake fluid in the average vehicle may contain as much as two percent water after only a year of service. After several years, it is not unusual to find brake fluid that contains as much as seven to eight percent water.
Excessive water content will decrease the boiling point of brake fluid and increase the risk of vapour lock.
The compression of a vapour lock when applying the brake pedal can lead to total hydraulic brake-system failure.
Water also promotes corrosion of important metal brake components.
The more moisture in the brake fluid, the lower the boiling point. This increases the risk of “brake fade.”
Under heavy driving conditions, such as towing, or on steep, winding roads or stop-start braking at high speeds, brake fluid boils, turns to vapour, and the brake pedal goes straight to the floor with no braking action.
This is known as “vapour-lock”.
If the police are called to such an accident, unless they test the boiling point of the brake fluid, all will appear normal: the brake fluid will have cooled back down, the brake pedal will feel firm, and the driver, having previously been unable to stop, will be faced with some serious questions.
AutoTest says there are several brake fluid testers on the market which measure just conductivity, however it states the most reliable method of determining the efficacy of your brake fluid is to boil it, which is exactly what the AutoTest Brake Fluid Tester does.
The AutoTest Brake Fluid tester is designed to test the boiling point of the fluid in the car in less than 30 seconds, with digital accuracy.
It works on all grades of brake fluid and shows clearly what the fluid has boiled at, and what the DOT minimums are for each, making the fluid change decision easy for the technician and the customer.
Once the brake fluid has been changed, garages can offer to re-test the brake fluid using the AutoTest Brake fluid tester, to clearly show the improved results on the new fluid.
For more information visit www.autotest.net.au