It is no surprise that brake problems are one of the most common issues faced by vehicle owners. The braking system has so many parts that wear out with time and should be replaced. In a brake system, the brake shoes, rotors, brake pads and brake fluid need the most frequent replacement while problems with the wheel cylinders, master cylinders, proportioning valve, brake booster and brake line are less common.
It is not a good idea to ignore any braking problem as they often indicate a certain part that require replacement or repair. To check for any braking problem, step on the pedal then press it down paying attention to how it feels under the foot. As a car owner, it is prudent to know the cause of common brake problems and how to fix them. Here is an overview of the most common braking problems and how to fix them.
Low brake fluid
This may be as a result of a leak in the brake system. You should inspect the brake hoses, wheel cylinder, master cylinder and the brake lines and if you detect a leak, the defective component should be rebuilt or replaced. A defective component poses a serious safety hazard therefore, the vehicle should not be driven until the repair is made.
Low brake pedal
This often occurs if the shoe adjusters on the drum stick fails to compensate the normal lining wear. Adjusting them will restore the full pedal but unless the adjuster is replaced or cleaned, the problem will occur again when the linings wear out. Other causes of a low pedal rake include fluid leak or worn out brake lining.
Soft or spongy pedal
This occurs when there is air in the brake system either due to improper bleeding, low fluid level or fluid loss. The best way to fix this is to bleed the brakes using the recommended sequence for your vehicle. Another cause of this problem is a ballooning rubber brake hose when the brakes are applied.
Excessive pedal travel
Possible causes of this include misadjusted drum brakes, worn brake linings or air in the brake lines. It is quite a dangerous condition as the brake system can run out of the pedal when the vehicle is still on the road.
Pedal sinking to the floor
This is a dangerous problem caused by leaks in the hydraulic system or worn out internal rubber seals preventing the brakes from holding pressure.
This problem indicates a damaged brake rotor that require replacement or resurfacing. The faces of the rotor should be parallel; within 0.0005 inches or 0.0127mm in most cars, they should never be more than .002 inch or 0.050 mm of run out. The wheel bearings should also be inspected, cleaned and repacked with grease. You may also need new grease seals.
A scraping noise
This noise usually indicates metal to metal contact. In this case, rotor and drum replacement will be needed together with new linings and brake hardware.
This is often caused by a vibration between the caliper and the disc pads which can be fixed by replacing or resurfacing the rotors, installing new pads or applying a noise compound or brake grease at the back of the pads.
This braking problem is caused by incorrectly machined rotors and the process was not finished properly.
Brake fluid, oil or grease fluid on the linings makes the brakes to grab. To fix this, you need to identify and eliminate the contamination then replace the linings. Badly scored rotors or drums can also grab and they may need to be replaced or resurfaced.
The dragging leads to increased fuel consumption and a steering pull. The drag also accelerates the wearing out of the brakes and makes the brakes to become hot which increases pedal effort and risks the brakes fading if they become too hot.
Dragging brakes is caused by a broken or a weak retracting springs on the drum brakes, a corroded or jammed caliper piston, floating caliper with corroded bushings or mounting pins, frozen emergency brake cable or overextended drum brake self adjuster.
Brakes pull to one side
This is caused by misadjusted brakes, contaminated linings, dragging brakes, a bad wheel caliper or cylinder or loose wheel bearings. It can also be caused by differences in rotor thickness or unequal friction on the front brakes.
Hard brake pedal
Lack of power assist is often caused by a low engine vacuum, a defective brake booster or a leaky vacuum hose to the brake booster. The booster is located between the firewall and the master brake cylinder in the engine compartment. Sometimes, a damaged check valve makes the vacuum to bleed out of the booster leading to hard pedal when the brakes are applied.
This condition can be fixed by starting the engine in order to build vacuum then shutting it off and waiting for about five minutes and trying the brakes if there is a power assist. If there is no, you will need to replace the check valve.
For vehicles equipped with power brakes, a hard brake pedal is caused by low fluid level, loose power steering pump belt, faulty valves or leaks in the power hose.
On cars that use ABS pump to generate brake boost, a problem with the high pressure accumulator or the ABS pump leads to loss in power assist. This makes the ABS warning light to come on and the ABS system and also sets a fault code corresponding to the problem that needs a scan tool to read.
If your brakes system grind, sequel or it causes a jerky stops or the warning light flashes, you should have the entire system inspected by professional mechanics.