When your vehicle starts pulling to one side or you hear a screeching noise every time you apply the brakes, you might be dealing with a sticking brake caliper. Not only can this issue affect your car’s handling and safety, but it can also lead to increased wear and tear on your brake system. Luckily, fixing a sticking brake caliper is a manageable task for most DIY enthusiasts. In this blog, we’ll guide you through the process step-by-step.
What is a Brake Caliper?
The brake caliper plays a crucial role in your car’s disc braking system. Its main function is to exert pressure on the brake pads, which then come into contact with the rotors (the circular metal discs that rotate along with the wheels) in order to slow down or bring your vehicle to a halt.
How Does a Brake Caliper Work?
Before we dive to the main content, let’s understand how the brake caliper works.
A brake caliper is a component of disc braking systems that functions as a clamp to slow or stop your vehicle’s wheels by creating friction with the rotors. Let’s take a closer look at how it works:
When you step on the brake pedal, it activates the master cylinder located under the hood, which then pushes brake fluid through the brake lines towards the brake calipers. This fluid transfer occurs under high pressure, necessary to move the components within the caliper.
Inside each caliper, there are one or more hydraulic pistons which are pushed outward by the pressure of the brake fluid. These pistons apply force directly to the brake pads, which are components made of a high-friction material. The brake pads are mounted within the caliper with their friction surface facing the metal disc known as the rotor.
As the pistons push the pads, they come into contact with the rotor, which is attached to the wheel. Since the rotor spins along with the wheel, pressing the brake pads against the rotor generates friction. This friction converts the kinetic energy of the moving vehicle into thermal energy (heat), effectively slowing down the rotation of the wheels and thereby slowing or stopping the vehicle.
The effectiveness of a brake caliper depends on several factors, including the condition of the brake pads and rotor, the quality and level of brake fluid, and the proper functioning of the caliper’s pistons and sliding pins (in the case of floating calipers). Regular maintenance is necessary to ensure that every component works efficiently, providing safe and reliable braking performance.
Types of Brake Calipers
Fixed Calipers
Fixed calipers are typically used in performance vehicles and offer more precise braking. Unlike floating calipers, fixed calipers do not move relative to the rotor.
This type of caliper has pistons positioned on both sides of the rotor, allowing them to apply pressure to the brake pads more evenly and simultaneously. This design minimizes the flexing of the caliper body and ensures consistent, powerful braking.
Floating Calipers
Floating calipers are the most common type found in passenger vehicles. They are named for their ability to move (or float) laterally to the rotor.
Floating calipers operate with one or two pistons on only one side of the rotor. When the brake is applied, the piston(s) push the inner brake pad against the rotor. Then, the caliper slides on its mount to bring the outer pad into contact with the other side of the rotor. This action clamps the rotor between the brake pads to create friction and slow the vehicle.
Sliding Calipers
Sliding calipers are a variation of the floating caliper design, also known as pin-slide calipers. They are similar in construction but include enhancements that aid in maintaining even braking.
Like floating calipers, sliding calipers have one or two pistons on only one side of the rotor. However, these calipers are mounted on a set of pins or slides that allow them to move more precisely along a horizontal axis. This mechanism helps balance the pressure applied to the brake pads, promoting more even wear and consistent performance.
Also Read: How to Replace Wheel Bearings: A Step-By-Step Guide
How To Fix a Sticking Brake Caliper
Dealing with a sticking brake caliper requires having the correct tools readily available. Being prepared with the right equipment will help ensure a smoother and safer process. Below is a list of the tools and materials necessary for the job:
Tools and Materials Needed:
- Jack and Jack Stands: To safely lift and support the vehicle.
- Wheel Chocks: To secure the vehicle and prevent it from rolling.
- Lug Wrench or Impact Wrench: For removing the wheel.
- Ratchet and Socket Set: Needed for various bolts and fasteners.
- Brake Caliper Piston Tool: This tool is used to retract the piston back into the caliper housing.
- C-Clamp: An alternative to a caliper piston tool for pushing the piston back.
- Caliper Pin Grease: High-temperature grease specifically designed for brake parts.
- Brake Cleaner: For cleaning the caliper and surrounding area.
- Wire Brush: Helpful for cleaning corrosion and buildup off the caliper and pins.
- New Brake Pads and Rotors (if needed): In case the current ones are worn or damaged.
- Torque Wrench: To ensure all bolts are tightened to the specified torque.
- Brake Fluid: You may need to top up or replace brake fluid after the job.
- Bleeder Wrench or Pliers: For bleeding the brake system.
- Clear Tubing and Collection Bottle: For a clean brake bleeding process.
- Gloves and Safety Glasses: To protect your hands and eyes from brake dust and fluids.
- Flashlight or Work Light: To improve visibility in the work area.
Steps to Fix a Sticking Brake Caliper
1. Prepare the Vehicle
When you begin work, it’s crucial to prioritize safety – both for yourself and for the vehicle. Place wheel chocks behind the wheels to stop the vehicle from moving. Utilize a jack to raise the car and then use jack stands to securely hold it in place. This will give you a reliable base to carry out your work on.
2. Remove the Wheel
Removing the wheel gives you access to the brake caliper and associated components. Use a lug wrench or impact wrench to loosen and remove the lug nuts, then carefully remove the wheel, setting it aside in a safe place.
3. Inspect and Clean the Caliper
With the wheel off, the brake caliper is now accessible. Use brake cleaner to spray down the entire caliper assembly and rotor, removing any built-up brake dust, grease, and road debris. A wire brush can be used to scrub away stubborn grime and rust, particularly around the caliper piston and sliding pins.
4. Check and Lubricate the Sliding Pins
The sliding pins are crucial for allowing the caliper to move freely as the brakes are applied and released. Remove these pins, inspect them for wear or damage, clean them thoroughly with a wire brush, and then lubricate them using high-temperature grease designed for brake systems. This ensures they move smoothly without sticking.
5. Compress the Caliper Piston
Over time, the caliper piston may not retract fully, contributing to the sticking issue. Use a caliper piston tool or a C-clamp to gently press the piston back into the caliper body. This step is critical to provide space for new brake pads if they are being replaced or to simply ensure the caliper operates correctly.
6. Reassemble the Brake Assembly
Once all parts are clean, lubricated, and moving freely, reassemble the brake components. If you’re replacing the brake pads or rotor, install them now. Ensure everything is aligned correctly and secured tightly. The use of a torque wrench is recommended to tighten all bolts to the manufacturer’s specified torque settings, ensuring consistent, safe brake performance.
7. Bleed the Brakes
Anytime you work on the brake system, there’s a potential for air to enter the lines, which can affect braking efficiency. Use a bleeder wrench and attach a piece of clear tubing to the bleeder valve on the caliper. Open the valve and have an assistant press the brake pedal to purge air from the system, collecting any expelled brake fluid into a container. Repeat until no air bubbles are visible in the fluid coming out.
8. Test Drive
After all repairs and adjustments, the final step is to test drive the vehicle. This should be done cautiously, in a safe area where you can test the brakes at various speeds without risk. Listen for any unusual noises, and pay attention to how the brake pedal feels. Ensure the vehicle does not pull to one side, which could indicate uneven braking.
Frequently Asked Questions (FAQs)
Can I fix a sticking brake caliper myself, or should I always go to a mechanic?
While many brake issues should be handled by a professional, fixing a sticking brake caliper can be a manageable task for someone with basic mechanical skills and the right tools. If you feel confident in your abilities and follow the steps outlined carefully, you can undertake this repair yourself. However, if the problem persists or you are unsure, it’s wise to consult a professional.
How often should I check my brake calipers for potential issues?
It’s good practice to inspect your brake calipers during regular vehicle maintenance or at least once a year. If you live in a region with harsh weather conditions, such as salted roads in the winter, more frequent inspections are advisable as these conditions can accelerate wear and corrosion.
What are the risks of ignoring a sticking brake caliper?
Ignoring a sticking brake caliper can lead to increased wear on your brake pads and rotors, potentially causing uneven braking and increased stopping distances. In the worst case, it could lead to brake failure, which is a significant safety risk.
Are there any specific signs that indicate a caliper is not just sticking but needs to be replaced?
Yes, if the caliper is severely corroded, the piston does not retract at all, or there are visible leaks of brake fluid from the caliper, it may need to be replaced entirely. In these cases, it’s advisable to seek professional help to ensure proper handling and replacement.
Can sticking brake calipers affect my car’s fuel efficiency?
Yes, a sticking brake caliper can cause drag on the affected wheel, leading to decreased fuel efficiency. Resolving the issue not only improves safety but can also help in maintaining better fuel economy.
What type of lubricant is best for brake caliper slider pins?
A high-temperature silicone-based grease is generally recommended for lubricating brake caliper slider pins. This type of lubricant withstands the high temperatures generated by braking without breaking down, ensuring smoother operation over time.
Also Read: Noise When Braking at Low Speed – Causes and Fixes
Conclusion
Fixing a sticking brake caliper is not only a vital part of maintaining your vehicle’s safety, but it also enhances your car’s overall performance and efficiency. By following the detailed steps outlined in this guide, even those with basic mechanical skills can address this common issue effectively and ensure their braking system functions optimally. Regular maintenance and timely repairs are crucial to avoid the more serious consequences of neglecting such an essential component of your vehicle. Remember, when in doubt, consult a professional to ensure your car remains in the best possible condition. Keep your brakes in check, and you’ll enjoy a smoother, safer drive every time you hit the road.