What to do if you find your car brakes fail
If you press the brake pedal and it goes down slowly, while the brake fluid level remains unchanged, then it definitely looks like the master cylinder piston cup is ripped up. To resolve this issue, you’ll have to find a way to get to the repair shop, but keep your speed down to 20 km/h.
Remember: rear brakes are almost three times less efficient than the front ones. Try on the handbrake lever. You’ll be limited to handbrake only at least for some time – it can lock the rear wheels independently from the primary brake system.
Don’t forget about the engine braking. When you’re about to lower the speed, don’t shift out of gear and don’t press the clutch.
If the brakes fail when you find yourself rolling downhill (surprise, surprise), try the following: shift down, then gradually release the clutch. Upon that the wheels will start accelerating the engine, wherein they’ll require approximately the same amount of torque as the engine needs to accelerate to proper speed. After reducing speed noticeably, shift to lower gear. Having made it to the first gear, try changing to reverse. Having slowed down to the lowest possible speed, key off the ignition – without throwing out of gear that is!
The second type of brake failure is characterized by poor car acceleration, short wheel out path (the car’s free running is hampered, it stops pretty quickly), by a specific acrid smell of burning brake linings. In such instance, the first thing you gotta do is wet your finger and touch each disc with it.
If any of the discs hisses (or is hotter than the others) it is this wheel that has a jammed brake cylinder.
If it’s a rear wheel that is the hot one, check whether you have taken the handbrake off before the ride! This “malfunction” is the most common among others.
If the brakes have jammed, do the following: raise the hot wheel off the ground, take it off. Thereby the brake pads and the clamping mechanism will be in front of your eyes.
If there are two calipers, try prying both pads up with a screwdriver to unclamp them from the disc. An operating caliper allows the cylinder to sink easily; while the jammed one hinders the cylinder strokes (you can use a screwdriver as a wedge, as a last resort measure, driving it between a disc and a pad).
If it’s a single caliper, try knocking it with a hammer (wrench) through a wooden lining (make sure it’s wooden! The caliper may crack from being hit by a piece of metal).
After you’ve unclamped the pads, get behind the wheel and press the brake with all you got. Then “shove” the caliper cylinders back in place again. Repeat the procedure several times.
If the brakes don’t come back to life after five or six such attempts, the caliper has to go – it needs to be replaced. To get to the repair shop, unclamp the pads again and block the brake pipe with a piece of rubber.
Even if manufacturers do configure a car with brake drums nowadays, those may only be mounted on the rear axle. In this situation, after removing the wheel from a hot drum, knock the drum off with a hammer or other heavy object, directing the blows outwards the body (knock the drum edge crosswise, or slowly circle-wise). Sink the pistons into cylinders tapping the surface of the pads lightly. Put the drum back in place, press and release the brake pedal several times (fully sunk pads sometimes fall short of clamping the drum after the first attempt), spin the drum.
If the drum is spinning, mount the wheel back. If not, repeat the cycle again. If the brakes don’t come back to life after five or six such attempts, the drum is done – get it replaced. To be able to make it to the repair shop, unclamp the pads again and block the brake pipe.