Checking your trailer brakes is crucial for safe towing and preventing accidents. The process involves both visual inspections and practical tests to ensure proper function and responsiveness.
Understanding Trailer Brake Systems
Electric Brakes: The Most Common Type
Most trailers utilize electric brake systems, where an electrical signal from the tow vehicle activates electromagnets within the brake drums. These magnets then engage the brake shoes against the drum, creating friction and slowing the trailer. Other, less common systems include surge brakes and air brakes, but this article primarily focuses on electric brakes due to their widespread use.
Components to Inspect
Before diving into the specific steps, familiarize yourself with the key components of your trailer brake system:
- Brake Controller: Located in the tow vehicle, it sends the electrical signal to the trailer brakes.
- Wiring Harness: Connects the tow vehicle to the trailer, transmitting the electrical signal and other essential functions like lights.
- Breakaway Switch: A crucial safety device that applies the trailer brakes if the trailer becomes detached from the tow vehicle.
- Brake Drums: The rotating components that the brake shoes press against to slow the trailer.
- Brake Shoes: Lined with friction material, they press against the brake drums to create stopping power.
- Electromagnets: Activated by the electrical signal, they engage the brake shoes.
- Springs and Hardware: Hold the brake components in place and ensure proper function.
- Bearings: Allow the wheels to rotate smoothly, critical for brake performance.
Step-by-Step Guide to Checking Your Trailer Brakes
1. Visual Inspection
Begin with a thorough visual inspection:
- Wiring: Check the entire wiring harness for any signs of damage, corrosion, loose connections, or frayed wires. Pay close attention to the connection points between the tow vehicle and trailer.
- Breakaway Switch: Ensure the breakaway switch is properly connected and the cable is in good condition. Test the switch by pulling the pin; the trailer brakes should immediately engage.
- Brake Drums: Examine the brake drums for cracks, rust, or signs of excessive wear.
- Brake Shoes: If possible (some brake assemblies require disassembly), inspect the brake shoe linings for wear. If the linings are thin or worn unevenly, they need replacement.
- Springs and Hardware: Check for broken or corroded springs and hardware. Replace any damaged components.
- Bearings: Look for any signs of bearing failure, such as grease leaking from the hub or excessive play in the wheel.
2. Brake Controller Testing
Next, test the brake controller in your tow vehicle:
- Gain Setting: Start with a low gain setting and gradually increase it until you feel the trailer brakes engaging properly. A properly adjusted gain setting is crucial for balanced braking.
- Manual Override: Use the manual override lever on the brake controller to apply the trailer brakes independently of the tow vehicle brakes. Listen for the trailer brakes engaging smoothly and consistently.
3. Dynamic Testing (Low Speed)
Perform a dynamic test in a safe, open area:
- Low-Speed Stop: Drive the tow vehicle and trailer at a slow speed (around 5 mph) and apply the trailer brakes using the manual override. The trailer should slow down smoothly and evenly without any pulling or jerking.
- Brake Bias Check: Drive at a slightly higher speed (around 20 mph) and apply both the tow vehicle and trailer brakes simultaneously. Observe how the trailer tracks. If the trailer pulls to one side, it indicates a brake imbalance that needs to be addressed.
4. Professional Inspection
If you’re uncomfortable performing these checks yourself or if you suspect a more serious problem, consult a qualified trailer mechanic. A professional inspection can identify issues that are not readily apparent and ensure that your trailer brakes are in optimal condition.
Troubleshooting Common Issues
Uneven Braking
Uneven braking can be caused by several factors, including:
- Contaminated Brake Shoes: Grease, oil, or brake fluid on the brake shoes can reduce their effectiveness.
- Worn Brake Shoes: Unevenly worn brake shoes can result in inconsistent braking power.
- Adjustments: Incorrectly adjusted brakes can cause one side to brake harder than the other.
- Faulty Electromagnet: A malfunctioning electromagnet can reduce the braking force on one side.
Weak Braking
Weak braking can be attributed to:
- Low Gain Setting: The brake controller gain may be set too low.
- Worn Brake Shoes: Worn or glazed brake shoes reduce friction.
- Faulty Electromagnet: A weak electromagnet may not be applying enough force to the brake shoes.
- Poor Wiring Connection: A corroded or loose wiring connection can reduce the electrical signal to the brakes.
Brakes Locking Up
Brakes locking up is a dangerous situation and can be caused by:
- High Gain Setting: The brake controller gain may be set too high.
- Over-Adjusted Brakes: Over-adjusted brakes can cause the brake shoes to drag and eventually lock up.
- Faulty Brake Controller: A malfunctioning brake controller may be sending excessive voltage to the brakes.
Frequently Asked Questions (FAQs)
FAQ 1: How often should I check my trailer brakes?
You should check your trailer brakes before each trip, especially long trips. At a minimum, inspect them every three months. This frequency allows for early detection of wear and tear or potential malfunctions.
FAQ 2: What tools do I need to check my trailer brakes?
Basic tools include a multimeter (for checking electrical connections), a jack, jack stands, a lug wrench, a screwdriver set, pliers, and a wire brush for cleaning connections. A brake adjusting tool may also be necessary.
FAQ 3: How do I adjust my trailer brakes?
Most electric trailer brakes are self-adjusting. However, you may need to manually adjust them occasionally. Consult your trailer’s owner’s manual for specific instructions. Typically, this involves accessing the adjuster star wheel through a slot in the backing plate and turning it until the brakes drag slightly, then backing off a few clicks.
FAQ 4: What is the proper gain setting for my brake controller?
The proper gain setting depends on the weight of your trailer and the braking power required. Start with a low setting and gradually increase it until the trailer brakes engage smoothly and proportionally with the tow vehicle brakes. If the trailer brakes lock up, reduce the gain. The goal is balanced and controlled stopping power.
FAQ 5: How do I test the breakaway switch?
With the trailer connected to the tow vehicle, pull the pin from the breakaway switch. The trailer brakes should immediately engage and hold the trailer firmly in place. Reinsert the pin to release the brakes.
FAQ 6: What does it mean if my trailer brakes are making a squealing noise?
A squealing noise can indicate worn brake shoes, glazed brake drums, or foreign material lodged between the brake shoes and the drum. Inspect the brakes thoroughly and replace any worn components. Cleaning the drum surface can sometimes resolve the issue.
FAQ 7: Can I replace my trailer brakes myself?
Replacing trailer brakes is a relatively straightforward process, but it requires some mechanical knowledge and experience. If you are not comfortable working on brakes, it is best to have a qualified mechanic do the job. Incorrect installation can lead to serious safety issues.
FAQ 8: How do I identify the type of brakes on my trailer?
Most trailers equipped with electric brakes will have a wiring harness and a breakaway switch. Surge brakes will have a hydraulic actuator at the front of the trailer tongue that compresses when the tow vehicle slows down. Air brakes are less common on smaller trailers and involve an air compressor and brake chambers.
FAQ 9: What causes trailer brakes to smell like they’re burning?
A burning smell usually indicates overheated brakes, which can be caused by over-adjusted brakes, dragging brakes, or excessive braking. Stop immediately and allow the brakes to cool down before proceeding. Investigate the cause of the overheating and correct it.
FAQ 10: How do I protect my trailer brakes from corrosion?
Regular cleaning and lubrication of brake components can help prevent corrosion. Apply a rust inhibitor to exposed metal surfaces. Proper storage in a dry environment also helps to minimize corrosion.
FAQ 11: What is involved in replacing brake shoes and drums?
Replacing brake shoes and drums involves jacking up the trailer, removing the wheel, disassembling the brake assembly, installing new brake shoes and drums, adjusting the brakes, and reassembling everything. It’s crucial to ensure proper adjustment to prevent dragging or weak braking.
FAQ 12: How do I know when my brake drums need to be turned or replaced?
Brake drums should be turned (machined) if they are scored or have minor imperfections. If the drums are cracked, warped, or have excessive wear, they should be replaced. Many drums also have a maximum diameter specification marked on them, indicating when they are too thin to safely use.