Worn brake rotors produce annoying vibrations and pulsations through your steering wheel, not to mention they impact your car’s braking performance. In many cases, you don’t need to replace them; resurfacing your rotors may be enough. Here’s how to determine if your rotors can be resurfaced and a step-by-step guide on how to go about it. One of the most important safety features in your vehicle is your brake system. Making sure all components are in proper working order is paramount to the overall safety of yourself and your passengers. When a brake system is not functioning properly, it may lead to a catastrophic event.
Brake calipers require pistons that extend outward to press on the brake pads to make contact with the rotors, which spin with your tires. This friction slows the rotation of the tires and ultimately the wheels. As the pads wear down over time, the pistons automatically adjust and extend further to maintain contact with the rotors. Rotors often warp from heat caused by hard braking or towing heavy loads. If there isn’t enough material left on the rotor, resurfacing won’t be possible. To check the thickness of your rotors, you’ll need a micrometer. Insert the micrometer’s spindle into one of the rotor’s cooling slots and measure the thickness. Compare the measurement to your vehicle’s manufacturer’s specifications, which are often etched into the rotor itself.
Resurfacing your rotors is an easy way to save money and time. If you’re comfortable working on your car, you can do it yourself in a few hours. Here’s what you’ll need: – Lug wrench – Jack and jack stands – Socket wrench – Wire brush – Brake cleaner – New brake pads – Rotor resurfacing kit. Once you have all of your tools and materials, you can follow these steps to resurface your rotors:- Remove the wheel from the car. – Remove the brake caliper from the rotor. – Remove the rotor from the hub. – Clean the rotor with a wire brush and brake cleaner. – Mount the rotor on the resurfacing kit. – Resurface the rotor following the manufacturer’s instructions. – Reassemble the brakes and wheels.
Rotor Resurfacing: An Overview
Rotor resurfacing, also known as brake rotor resurfacing or brake rotor truing, is a machining process that restores the surface of brake rotors to their original condition. It removes any imperfections, such as scratches, grooves, or warps, that can cause braking problems. Resurfacing rotors can help to improve braking performance, reduce noise, and extend the life of the rotors.
Resurfacing rotors is a relatively simple and inexpensive procedure that can be performed by a mechanic or do-it-yourselfer with the right tools. The process typically involves removing the rotors from the vehicle, cleaning them, and then using a brake lathe to machine the surface of the rotors. The lathe removes a thin layer of material from the rotors, leaving them smooth and flat. Once the rotors are resurfaced, they can be reinstalled on the vehicle.
There are several benefits to resurfacing rotors. First, it can improve braking performance. When rotors are warped or have imperfections, they can cause the brakes to grab or pulsate. Resurfacing the rotors can eliminate these problems and restore smooth, even braking.
Second, resurfacing rotors can reduce noise. Warped or damaged rotors can create a squealing or grinding noise when the brakes are applied. Resurfacing the rotors can eliminate these noises and make the brakes quieter.
Third, resurfacing rotors can extend the life of the rotors. When rotors are worn or damaged, they can be more likely to crack or break. Resurfacing the rotors can remove any imperfections that could lead to failure and extend the life of the rotors.
| Pros of Rotor Resurfacing | Cons of Rotor Resurfacing |
|---|---|
| Improves braking performance | Can remove too much material, weakening the rotors |
| Reduces noise | May not be effective if the rotors are severely damaged |
| Extends the life of the rotors | Can be more expensive than replacing the rotors |
Assessing Rotor Damage
Evaluating the severity of rotor damage is crucial before considering resurfacing. Here’s a detailed assessment process:
Visual Inspection
Thoroughly examine the rotors for signs of damage, such as:
| Damage Type | Description |
|---|---|
| Warped Rotors | Uneven surface, causing vibrations and reduced braking performance |
| Grooves | Deep incisions created by friction, reducing rotor thickness and braking efficiency |
| Scoring | Fine lines resulting from overheating or brake pad material transfer, affecting braking smoothness |
| Cracks | Major safety hazard, requiring rotor replacement |
Micrometer Measurement
Use a micrometer to measure the rotor thickness at multiple points along its surface. Compare the readings to the manufacturer’s specifications. If the thickness is below the minimum specified, the rotors must be replaced.
Runout Test
Mount the rotors on a lathe or a hub and rotate them while using a dial indicator to measure runout. Excessive runout (>0.002 inches) indicates warped rotors and necessitates replacement.
The Importance of Rotor Balance
Properly balanced rotors are essential for smooth and safe vehicle operation. Imbalances can cause vibrations, premature wear on suspension components, and reduced braking efficiency.
Types of Rotor Imbalances
There are two main types of rotor imbalances:
- Static imbalance: Occurs when the center of mass of the rotor is offset from its geometric center. This causes the rotor to wobble as it spins.
- Dynamic imbalance: Occurs when the mass distribution of the rotor is uneven along its axis of rotation. This causes the rotor to vibrate and bounce.
Consequences of Rotor Imbalance
Unbalanced rotors can cause a range of problems, including:
- Vibrations: Excessive vibrations can be felt through the steering wheel, seat, or floorboard.
- Premature wear: Imbalances put stress on suspension components, leading to accelerated wear and tear.
- Reduced braking efficiency: Imbalances can affect the contact patch between the brake pads and rotors, reducing braking performance.
- Nuisance noises: Rotor imbalances can generate annoying noises, such as squealing or grinding.
To ensure optimal vehicle performance and safety, it is crucial to have rotors balanced regularly. This involves using a specialized machine to detect and correct any imbalances, restoring the rotors to their proper balance.
Tools and Equipment Required
Resurfacing rotors requires specialized tools and equipment. The following list outlines the essential items you’ll need:
On-Car Brake Lathe
An on-car brake lathe is a machine that mounts directly onto the vehicle’s wheel hub, allowing you to resurface the rotors while they are still attached to the vehicle. This method is the quickest and most efficient, as it eliminates the need to remove the rotors.
Bench Brake Lathe
A bench brake lathe is a standalone machine used to resurface rotors that have been removed from the vehicle. While less efficient than an on-car lathe, it is a more affordable option.
Micrometer or Dial Indicator
A micrometer or dial indicator is used to measure the thickness of the rotors and ensure they meet specifications.
Brake Caliper Compressor
A brake caliper compressor is used to compress the brake calipers, providing access to the rotors.
Impact Wrench
An impact wrench is used to loosen and tighten the lug nuts that hold the rotors in place.
Table of Essential Tools and Equipment
| Tool | Function |
|---|---|
| On-Car Brake Lathe | Resurfacing rotors on vehicle |
| Bench Brake Lathe | Resurfacing rotors off vehicle |
| Micrometer or Dial Indicator | Measuring rotor thickness |
| Brake Caliper Compressor | Compressing brake calipers |
| Impact Wrench | Loosening and tightening lug nuts |
Step-by-Step Guide to Resurfacing Rotors
1. Safety Precautions
Wear safety glasses and gloves to protect yourself from flying debris. Ensure the vehicle is parked on a level surface and the parking brake is engaged.
2. Remove the Wheels
Loosen the lug nuts with a lug wrench and raise the vehicle using a jack. Remove the lug nuts and wheels.
3. Remove the Caliper
Unbolt the caliper from the caliper bracket and carefully remove it. Hang the caliper from the suspension using a wire or bungee cord.
4. Prepare the Rotor for Resurfacing
Clean the rotor with brake cleaner and remove any rust or debris. If the rotor is heavily rusted, it may need to be replaced.
5. Resurface the Rotor
Using a Lathe
Mount the rotor on a lathe and use a cutting tool to remove material from the surface of the rotor. The rotor should be resurfaced to the specifications provided by the manufacturer.
| Rotor Thickness | Resurfacing Thickness |
|---|---|
| 12.0 mm | 11.9 mm |
| 11.5 mm | 11.4 mm |
| 11.0 mm | 10.9 mm |
Using a Grinder
Use a high-quality angle grinder with a fine-grit grinding wheel. Hold the grinder parallel to the rotor surface and carefully remove material until the desired thickness is achieved.
Inspection
After resurfacing, inspect the rotor for any unevenness, cracks, or other defects. If any defects are found, the rotor should be replaced.
Common Troubleshooting Issues
### 1. Excessive Vibration
Excessive vibration after resurfacing can indicate warped rotors. Check the rotors for visual signs of warping or use a dial indicator to measure runout.
### 2. Noisy Braking
Noisy braking may be caused by uneven pad wear, glazed pads, or contamination on the rotor surface. Inspect the pads for uneven wear and clean or replace them as needed.
### 3. Poor Braking Performance
Poor braking performance can result from insufficient resurfacing, glazed rotors, or improper bleeding. Ensure that the rotors are resurfaced to the correct specifications, check for glazing, and bleed the brake system thoroughly.
### 4. Pedal Pulsation
Pedal pulsation can occur when the rotors are unevenly resurfaced or there is a buildup of brake dust on the rotor surface. Re-surface the rotors carefully and clean the rotors and pads thoroughly before reassembly.
### 5. Steering Wheel Shake
Steering wheel shake under braking may indicate a suspension issue, warped rotors, or imbalanced wheels. Check the suspension components for wear and tear and have the rotors inspected for warping. Balance the wheels as well.
### 6. Thickness Variation
Variations in rotor thickness can cause uneven braking and vibration. Use a micrometer to measure the rotor thickness at multiple points around the circumference. If the thickness exceeds manufacturers’ specifications, the rotors must be replaced.
| Parameter | Tolerance |
| Runout | 0.0005″ (0.013 mm) or less |
| Thickness Variation | 0.002″ (0.05 mm) or less |
Safety Precautions
Before beginning, always ensure your safety by taking the following precautions:
1. Park on a level surface and engage the parking brake.
This will prevent the vehicle from moving while you are working on the rotors.
2. Allow the vehicle to cool completely.
This is important to avoid burns or injuries from hot components.
3. Wear gloves and safety glasses.
These will protect your hands and eyes from debris and sparks.
4. Block the wheels opposite the ones you are working on.
This will prevent the vehicle from rolling.
5. Use a torque wrench to tighten the lug nuts.
This will ensure that the lug nuts are properly tightened and prevent them from loosening while you are driving.
6. Never attempt to resurface rotors that are cracked or severely warped.
Doing so could damage the rotors or cause them to fail.
7. Always follow the manufacturer’s instructions for your specific vehicle.
This will ensure that you are resurfacing the rotors correctly and avoid any potential damage.
| Tools and Equipment Needed |
|---|
| • Safety glasses • Gloves • Lug wrench • Torque wrench • Rotor resurfacing kit • Brake cleaner |
Things to Consider:
When deciding whether to resurface or replace rotors, several factors should be considered:
- Rotor Thickness: Rotors have a minimum safe thickness specified by the manufacturer. If the rotors are too thin, they may not be able to dissipate heat effectively, leading to brake fade or failure.
- Grooves and Scoring: Deep grooves or scoring on the rotor surface can indicate excessive wear. Resurfacing may be ineffective in removing these imperfections, necessitating rotor replacement.
- Warping: Warped rotors can cause vibrations during braking. Resurfacing may not resolve this issue, and rotor replacement is typically required.
- Rust and Corrosion: Excessive rust or corrosion on the rotor surface can weaken the metal and affect brake performance. Resurfacing can remove some rust, but severe corrosion may require rotor replacement.
- Brake Pad Material: The type of brake pads used can influence rotor wear. Metallic brake pads tend to be more abrasive than ceramic or organic pads, potentially requiring more frequent rotor resurfacing or replacement.
- Driving Conditions: Aggressive driving habits, such as frequent hard braking or driving in mountainous areas, can accelerate rotor wear. Resurfacing may be more frequent in these conditions.
- Vehicle Age and Mileage: Older vehicles with high mileage may experience increased rotor wear due to general wear and tear. Rotor replacement may be more appropriate than resurfacing.
- Visual Inspection: A visual inspection of the rotors can provide valuable information. If the rotors exhibit any of the aforementioned signs of excessive wear or damage, replacement may be necessary.
- Cost: Resurfacing rotors is typically less expensive than replacing them. However, if the rotors are severely worn or damaged, replacement may be more cost-effective in the long run.
Professional Advice on Rotor Maintenance
1. Check Rotor Thickness Regularly
Use a caliper to measure rotor thickness at the outer edge, inner edge, and center. Compare measurements to the manufacturer’s specifications. Replace rotors if thickness is below minimum.
2. Inspect for Rust
Look for surface rust on rotors. Minor rust can be removed with a wire brush. Replace rotors if rust is severe or covers large areas.
3. Check for Cracks
Examine rotors closely for any cracks or chips. Replace rotors with any visible cracks.
4. Clean Rotors
Remove dirt and debris from rotors using a brake cleaner. Clean the mating surfaces of the pads as well.
5. Lubricate Rotor Hub
Apply a thin layer of high-temperature grease to the rotor hub where it contacts the wheel bearing.
6. Torque Lug Nuts Properly
Uneven torquing can cause rotors to warp. Follow the manufacturer’s torque specifications for lug nuts.
7. Drive Responsibly
Avoid hard braking and sudden stops to reduce wear on rotors and other brake components.
8. Use High-Quality Pads
Cheap brake pads can wear rotors prematurely. Choose high-quality pads with a ceramic or semi-metallic composition.
9. Use a Torque Wrench for Caliper Bolts
Overtightening caliper bolts can damage rotors. Use a torque wrench to tighten bolts to the proper specification.
10. Resurface Rotors Carefully
Use a lathe specifically designed for resurfacing rotors. Remove only the minimum amount of material necessary to smooth out irregularities. Over-resurfacing can weaken rotors and shorten their lifespan. Here are some additional tips for resurfacing:
| Resurfacing Tips |
|---|
| – Use a fine grit sandpaper (220 or higher). |
| – Move the lathe slowly to avoid overheating. |
| – Check rotor thickness regularly during resurfacing. |
| – Clean and lubricate the rotor after resurfacing. |
How to Resurface Rotors
Resurfacing rotors is a relatively simple task that can help to improve the performance of your brakes. It is a process of removing a thin layer of material from the surface of the rotors, which helps to smooth out any imperfections and remove any rust or corrosion.
To resurface your rotors, you will need a set of brake pads, a rotor resurfacing kit, and a drill. You can also take your rotors to a machine shop to have them resurfaced.
To do it yourself, follow these steps:
- Remove the old brake pads.
- Attach the rotor resurfacing kit to your drill.
- Start the drill and slowly move the kit across the surface of the rotor.
- Continue until the entire surface of the rotor has been resurfaced.
- Install the new brake pads.
