Brake System Troubleshoot - screeching noise, dragging brakes, etc

General Automotive Repair

A brake in an automobile is a device for applying a force against the friction of the road, slowing or stopping the motion of a vehicle, or alternatively a device to restrain it from starting to move again. The kinetic energy lost by the moving part is usually translated to heat by friction. Alternatively, in regenerative braking, much of the energy is recovered and stored for later use.

Note that kinetic energy increases with the square of the velocity (E = 1/2·m·v2 relationship). This means that if the speed of a car doubles, it has four times as much energy. The brakes must therefore dissipate four times as much energy to stop it and consequently the braking distance is four times as long.

Brakes of some description are fitted to most wheeled vehicles, including automobiles of all kinds, trucks, trains, motorcycles, and bicycles. Baggage carts and shopping carts may have them for use on a moving ramp.

Deceleration and avoiding acceleration when going downhill can also be achieved by using a low gear; see engine braking. Friction brakes on cars store the heat in the rotating part (drum brake or disc brake) during the brake application and release it to the air gradually. Wikipedia:Brakes

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WARNING: Take care not to breath in brake dust. Brake dust is filled with asbestos which causes mesothelioma cancer and or tumor. Mesothelioma destroys tissue and organs and have the potential to spread to other parts of the body. Always clean brake parts with a certified brake parts cleaner before working on the brake system. This will reduce the amount of exposure to asbestos.

The general troubleshooting information lists common vehicle symptoms with possible solutions and is not for any particular vehicle make and model. For repair info specifically for your make and model please view the main directory.

When Braking Car Pulls left or Right

• Incorrect tire pressure: Inflate tires to proper pressure
• Front end out of alignment
• Mismatched tires: Check tires sizes
• Restricted brake lines or hoses: Check routing of brake line hose
• Loose or malfunctioning brake caliper
• Bent brake shoe or oily linings in the drum brakes
• Malfunctioning rear brakes
• Loose suspension parts

Strange Screeching or Squealing Noise without Brakes Applied

• Front linings worn out Replace linings
• Dust or oil on drums or rotors
• Metal brake cover behind brake rotor may have bent causing contact with brake rotor during driving. Excessive screeching noises will result.

Strange Screeching, Grinding Noise when Brakes are Applied

• Insulator on outboard shoe damaged
• Incorrect brake pads or linings: Replace pads or linings

Rough, Chattering or Pulsating Brake Pedal

• Excessive lateral runout: Check brake rotor runout
• brake Rotor may have warped due to extreme heat: Resurface or replace brake rotor
• Wheel bearings not adjusted
• Rear drums out-of-round: Resurface or replace drums
• Disc pad reversed, steel against rotor: Remove and reinstall pad

Car Takes More Effort to Stop

• Malfunctioning brake booster
• Partial system failure: Check fluid and pipes
• Worn disc pad or lining: Replace pad or lining
• Brake caliper piston stuck or sluggish
• Master cylinder piston stuck
• Brake fade due to incorrect pads for linings: Replace pads or linings
• Linings or pads glazed: Replace pads or linings
• Worn drums: Resurface or replace drums

Excessive Brake Pedal Travel

• Partial system failure: Check fluid and pipes
• Insufficient brake fluid in master cylinder
• Air trapped in brake system
• Rear brakes not adjusted
• Bent shoe or lining
• Plugged master cylinder cap
• Improper brake fluid: Replace brake fluid

Brake Pedal Travel Decreasing

• Compensating port plugged
• Swollen cup in master cylinder
• Master cylinder piston not returning
• Weak shoe retracting springs
• Wheel cylinder piston sticking

Brakes Keep Dragging

• Master cylinder pistons not returning
• Restricted brake lines or hoses: Check line routing
• Incorrect parking brake adjustment
• Parking Brake cables frozen
• Incorrect installation of inboard disc pad: Remove and replace correctly
• Power booster output rod too long
• Brake pedal not returning freely

Brakes Grab or Uneven Braking Action

• Malfunction of combination valve
• Malfunction of power brake unit
• Binding brake pedal

Pulsation or Roughness

• Uneven brake pad wear caused by caliper
• Uneven brake rotor wear
• Drums out-of-round

Take care not to breath in brake dust. Brake dust is filled with asbestos which causes mesothelioma cancer and or tumor. Mesothelioma destroys tissue and organs and have the potential to spread to other parts of the body. Always clean brake parts with a certified brake parts cleaner before working on the brake system. This will reduce the amount of exposure to asbestos.


General Automotive Repair

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