My car's brake fluid level indicator lit up the other day. As I felt the brakes were still working well, I topped up the brake fluid reservoir at a nearby petrol station. The warning light went off. How exactly is brake fluid consumed in the braking process? My car is two years old.

Unlike engine oil, brake fluid does not burn up anywhere in the braking system. So the first thing to check when fluid level drops is whether there are any leaks in the hydraulic brake lines.

Any brake fluid leak must be fixed immediately or it will ultimately result in total brake failure.

Unless the vehicle is damaged (perhaps in an accident), such leaks are highly unlikely - especially in a two-year-old car.

There is another reason why brake fluid level drops. When brake pads start to wear and thin out, the pistons in the brake calliper move further outwards and the space thus vacated fills up with fluid from the reservoir.

In cars that do not have a brake pad wear indicator, the fluid level warning serves as a signal that the pads need replacing.

When new pads are fitted, the calliper pistons are pushed back, causing the fluid to return to the reservoir. The fluid level will rise back to its normal level when all the pads are replaced.

SHREEJIT CHANGAROTH