Having issues with your brakes can be downright scary. But before you rush to the mechanic, there are a few troubleshooting steps you can take right in your own driveway. This guide will walk you through the most common brake problems, symptoms to look for, and tips to diagnose issues yourself.
With some basic mechanical knowledge and the right tools, you can identify and even fix minor brake problems. Read on for a comprehensive overview of DIY brake troubleshooting.
1. Regularly check brake fluid levels in the master cylinder to spot low fluid before it causes braking problems.
2. Inspect brake pads and rotors for wear and damage which can significantly impact braking ability if left unchecked.
3. Learn how to bleed brakes to remove trapped air that leads to a spongy pedal feel.
4. Test components like the brake booster and master cylinder for proper operation when braking issues arise.
5. Evaluate braking system symptoms like noises, pulling, and uneven pedal feel to isolate issues.
6. Conduct brake stop tests to measure actual stopping distances and assess if they are longer than expected.
7. Utilize professional help for complex repairs like stuck calipers, rotor replacement, major leaks, or ABS bleeding. Know your limits.
1. How to Check Brake Fluid Level
Low brake fluid is one of the most common causes of brake problems. Here’s how to check the level in your master cylinder:
- Clean rag
- Locate the master cylinder under the hood. It will be near the firewall on the driver’s side.
- Wipe off any dirt or debris from the reservoir cap.
- Unscrew the cap and look at the fluid level. It should be between the “Min” and “Max” lines.
- If it’s low, top it off with the recommended brake fluid type for your vehicle.
- Replace the reservoir cap and check levels again in a few days.
Signs of low fluid include brake warning lights, soft/spongy pedal feel, and sinking pedal. Low fluid can severely impact braking ability, so address it ASAP.
2. Inspect Brake Pads and Rotors
Worn brake pads are another very common issue. Use these steps to check pad thickness and rotor condition:
- Tire gauge or ruler
- Locate the brake caliper over each rotor. This is where the pads are housed.
- Insert the tire gauge or ruler between the rotor and pad. There should be 1/8″ to 1/4″ of clearance.
- Check that the pad material covers 2/3 of the rotor surface.
- Inspect the rotors for grooves, glazing, or bluing.
- Spin each rotor and watch for thickness variation or excess wobble.
If pads are worn, rotors are damaged, or anything looks abnormal, replacement is needed. Addressing worn pads helps prevent further brake and rotor damage.
3. Test for Air in the Brake Lines
Air trapped in the brake lines leads to a soft/spongy pedal feel. Bleeding the lines is needed to restore proper brake function.
- Brake bleeder wrench
- Clear tubing
- Brake fluid
- Locate the bleeder valve on each brake caliper.
- Attach tubing to the valve and submerge the end in brake fluid.
- Have your assistant pump the brakes 5-6 times.
- Turn the bleeder valve a half turn to release air, then close it.
- Repeat the pumping and bleeding sequence until no more bubbles come through the tube.
Bleeding all four wheels ensures you get all the trapped air out of the system. Take your time and monitor fluid levels in the master cylinder.
4. Test the Brake Booster
If braking takes excessive effort, the brake booster may need replacement. Here’s how to test it:
- Start the engine and let it idle.
- Firmly press the brake pedal several times to deplete vacuum reserve.
- With your foot on the pedal, turn off the engine.
- The pedal should sink down slightly as vacuum fades.
- If it doesn’t sink, the booster isn’t working properly.
The booster multiplies pedal force when braking. If it fails, you’ll need to apply much more pressure to slow and stop. Replace it ASAP if faulty.
5. Evaluate the Master Cylinder
A faulty master cylinder prevents adequate braking pressure. Follow these steps to test it:
- Brake pedal depressor tool
- Remove the master cylinder reservoir cap.
- Use the brake pedal tool to slowly depress the pedal.
- Watch for fluid movement in the reservoir as you apply pressure.
- If no bubbles or fluid displacement occur, the master cylinder is likely defective.
The master cylinder converts pedal motion into hydraulic pressure. Without it working properly, fluid can’t apply the pads/shoes. Replacement by a professional is recommended.
6. Diagnose Uneven Braking or Pulling
Uneven braking effort or pulling to one side while braking indicates a stuck caliper or fluid leak in a front brake. Inspect each front caliper for:
- Binding pistons or slider pins
- Leaking fluid
- Uneven pad wear
Either condition will prevent equal braking force. Stuck calipers must be rebuilt or replaced. Identify and repair any fluid leaks. Uneven wear indicates a larger underlying issue.
7. Listen for Brake Noises
Unusual brake noises often signal a problem. Here are the most common:
- Squealing – Glazing/wear on pad material
- Grinding – Metal-on-metal contact from worn pads
- Scraping – Debris buildup in brakes
- Clunking – Hardware failure
Address squeaking pads right away to prevent further damage. Grinding means pads must be replaced immediately. Identify and remove any stuck debris. Have hardware failures fixed by a professional.
8. Perform a Brake Stop Test
A brake stop test evaluates total brake system function. Conduct this on a dry, level, empty road:
- Tape or chalk
- Measuring tape
- Accelerate to 20 mph. Mark the start point.
- Firmly brake without locking wheels or activating ABS.
- Mark the end point when fully stopped.
- Measure the distance between the marks.
- Repeat test 2-3 more times and average the distances.
Typical stopping distances are 15-20 feet. Longer distances indicate brake problems. Adjustment or component replacement may be needed to restore proper brake function.
Common Brake Problems and Causes
Here is a quick reference of the most frequent brake issues, symptoms, and typical causes:
|Low brake fluid||Warning light, spongy pedal, sinking pedal||Leak, worn pads|
|Worn pads/rotors||Squealing, vibration, poor stopping, pulsating pedal||Pad material glazing/wearing down|
|Air in lines||Spongy pedal||Leak, low fluid|
|Faulty brake booster||Hard pedal, excessive effort to stop||Vacuum or mechanical failure|
|Bad master cylinder||Sinking pedal, no fluid movement||Internal seals failed|
|Uneven braking/pulling||Vehicle swerves under braking||Stuck caliper piston, brake fluid leak|
|Noises||Squeal, scraping, grinding||Glazed pads, debris, worn pads|
Frequently Asked Questions About Brake Troubleshooting
How often should I check my brake fluid?
You should check your brake fluid level every 1-3 months when doing routine underhood inspections. Top it off as needed to keep it between the “Min” and “Max” reservoir lines.
What brake fluid type should I use?
Consult your owner’s manual for the specific fluid recommended by the manufacturer. Using the wrong type can corrode brake parts. Common types are DOT 3, DOT 4, and DOT 5.1.
Can I drive with bad brake pads?
It’s not recommended to drive with worn brake pads. They can completely fail and lead to a brake emergency. Address worn pads right away to avoid further damage to rotors and calipers.
Does the parking brake need to be on when bleeding brakes?
No, you do not need the parking brake engaged when bleeding your brakes. The regular brake pedal is used for the pumping actions to push fluid through the lines.
Should I hear noises when applying brakes?
No. Brakes normally operate quietly and smoothly when working properly. Any noises like squealing or scraping mean inspection is needed to identify issues.
How do I know if rotors need to be replaced?
Rotors should be replaced if they are: excessively worn, deeply grooved/pitted, heat cracked, or exhibit thickness variation or excessive warping. They can become too thin or damaged to operate safely.
Can I replace brake pads myself?
With some DIY mechanical experience, brake pads can be replaced at home using basic tools like a C-clamp and torque wrench. Always follow the procedure in your vehicle repair manual.
What is a brake bleeder valve?
Bleeder valves are small valves on each brake caliper that allow air to be released from the hydraulic lines during bleeding. This valve is used to purge the system of trapped air.
When to Seek Professional Brake Repairs
While many brake issues can be tested at home, it’s critical to involve a professional mechanic for anything complex or safety related. Seek help for:
- Faulty master cylinders or brake boosters
- Stuck calipers requiring rebuild
- Replacing damaged rotors
- Bleeding ABS antilock brake systems
- Any major fluid leaks or component failures
Brakes are essential for vehicle safety, so don’t take chances on repairs beyond your skill level. Test and troubleshoot minor issues yourself, but utilize professional help when needed.
Knowing how to troubleshoot common brake problems allows you to be proactive with repairs and maintenance. Pay attention to symptoms and utilize these DIY diagnostic steps to identify issues before they become unsafe. Catching problems early saves money and prevents secondary damage too.
While some repairs require professional equipment and skills, there are many checks you can conduct yourself in your own driveway. Being comfortable with basic brake inspection empowers you to handle minor issues as they arise. Use this article as a reference to monitor your brakes and tell when they need attention.