What’s more important than hauling your RV or trailer to your destination? Being able to arrive safely and, of course, stop when you need to. Keeping your trailer brakes adjusted is crucial. And learning how to do this yourself will definitely come in handy.
How do you adjust trailer brakes? Here are 10 ways to adjust electric trailer brakes. Later, air brakes and surge brakes will be addressed.
- Gather the right tools
- Jack up wheel
- Free the wheel
- Remove adjusting hole cover
- Insert a flat-head screwdriver or brake adjusting tool
- Locate star wheel
- Click star wheel
- Free the wheel tire
- Clean out rust
- Replace cap
This is a simple process, but it does take some time. If your trailer brakes aren’t properly adjusted, it will put a strain on your vehicle’s brakes because the vehicle will be doing all the work. This can be a safety hazard. Whatever type of brakes you have, with a few tools and these steps, you’ll be back on the road in a jiffy.
10 Easy Steps to Adjusting Trailer Brakes
1. Gather the right tools
There are only a few tools needed to perform a proper trailer brake adjustment. They include:
- A rollaway jack or a bottle jack
- Flathead screwdriver or brake adjusting tool
- Gloves
- Safety goggles
- flashlight
2. Jack up the wheel
When raising a trailer’s wheel, always lift by the frame. Never lift with the axel. Do not go under the trailer unless the trailer is supported by jack stands. Lift a wheel off the ground one at a time. Your automobile jack may not be strong enough to lift your trailer. A trailer can be heavier than an automobile.
3. Free the wheel
Make sure the wheel is jacked up high enough so that if freely rotates.
4. Remove the adjusting hole cover
Remove the rubber adjusting cap. It’s located underneath the brake drum. This is below the brake backing plate in the back of the wheel. If it’s an older trailer, don’t be alarmed if the adjusting cap is missing. It’s still workable. Beneath the adjusting cap, you will find a slot.
5. Insert a screwdriver or brake-adjusting tool
Insert your screwdriver or adjusting tool into the slot.
6. Locate the star wheel
A specialized gear called a star wheel is in the slot. The star wheel’s teeth are uncovered on the edges. It’s called a star wheel because the teeth or ridges stick out in a star shape. With the inserted tool, feel around for the teeth in the star wheel. When you have a grip on one, you’ll find your tool won’t slip.
7. Click the star wheel
Push your end of the tool down, allowing the inserted end of the tool to go up. It’s a similar motion as a teeter-totter…up and down. You’ll hear a clicking noise. You’ll want to give it at least five clicks.
8. Freewheel the tire.
Freewheel the tire and see how it feels. You want to feel a little drag, so you know it’s barely touching the brake drum. But the wheel should still freely rotate. If you feel it needs more adjustment, insert the tool and listen for another click or two.
9. Clean out any rust
There might be some rust or scaling on the cast iron of the brake plate. This can happen if:
- You store your trailer outside
- Live in the Northeast
- Live in a damp or rainy area
As you adjust the brake, you’re going to have some of that scale knock off. Rotate the wheel a few times to clean some of it out.
10. Replace the cap
Replace the rubber cap. And you are finished.
What is an Electric Trailer Brake Controller?
Electric brakes use a brake controller in the towing vehicle’s cabin. Because electric brakes use electromagnets to initiate the drum brakes, you use the brake controller and the brake light circuit to control the electricity to the brakes.
The brake controller can also be used manually with your hand to apply a small amount of braking. This is usually done when a trailer begins swaying. This can happen:
- Descending a hill
- In high winds
- Being passed by large semi-trucks
How to Adjust an Electric Brake Controller
The brake controller is located in the cab of your vehicle. When engaged, it sends a signal from your vehicle’s brakes to your trailer’s brakes. This reduces the wear and tear on your rig’s brakes. It also stops the vehicle more safely. The following are the steps to adjusting your brake controller. We’ll go into each step in more detail below.
- Hook up the trailer to the vehicle
- Warm the trailer brakes
- Power control knob
- Release the accelerator while driving
- Braking action
- Driving test
- Fine-tune adjustments
1. Hook up the trailer to the vehicle
Connect the vehicle and the trailer. The electrical plug will be near the trailer hitch.
2. Warm the trailer brakes
Drive the vehicle at forty-five MPH. Apply the manual lever on the controller for around one-quarter of a mile. Make sure you have towed the trailer to a flat, dry area such as:
- Parking lot
- Field
- Deserted road
3. Power control knob
Do not turn off the engine. Set the power control knob on its mid-point setting.
4. Release accelerator while driving
Begin moving. Accelerate to twenty-five MPH and then release the gas pedal.
5. Maximum limit
Move the control lever to its maximum limit.
6. Braking action
Begin to brake. If you notice the wheels locking or skidding, turn the power level down. Continue brake and note how the brakes react. If the trailer doesn’t brake properly, turn up the power. If the wheels skid or lock, turn it down. Maneuver it until you have the braking action you desire.
7. Driving Test
Continue going back and forth with the power level. Test the breaks for several minutes. Remember, stay on a flat surface.
8. Fine-tune adjustments
Continue testing. Use the brake pedal to slow down or stop your vehicle. You want to be sure the trailer brakes are doing their share of the braking work. But you don’t want them skidding or grabbing.
How Often Should You Adjust Electric Trailer Brakes and the controller?
As the lining wears and drums wear through, more clearance between the lining and the drums occurs. At this point, the brakes will need to be adjusted.
Your trailer brakes should be adjusted about every three thousand miles or every three months. If you don’t keep your trailer brakes adjusted, you could have uneven braking. When that happens, your vehicle will start pulling to one side or the other. When you adjust your brakes, make it a point to adjust your controller as well. Other instances to adjust the brake controller one way or the other include:
- If the weight of the load you are towing changes: for heavier loads, increase the power.
- Weather can also affect the brake controller: when the roads are wet or otherwise slippery, you will want to decrease the power.
Adjusting Self-adjusting Air Brakes
Air brakes use compressed air to transmit pressure from the driver’s control to the brake. Air brakes are used in:
- Trailers
- Semi-trailers
- Buses
- Trucks
Even though they are self-adjusting, they will reach their tolerance at some point. When this happens, it’s time to adjust them. The following are the steps to adjusting self-adjusting air brakes.
- Gather the tools needed
- Jack up vehicle
- Find brake chamber
- Find adjustment nut
- Turn nut
- Distance push arm travels
- When to call a mechanic
1. Gather the tools needed
There are only a few basic tools needed to complete the job. They include:
- Gloves
- Open-ended wrench set
- Jack
- Jack stand or chocks
2. Jack up vehicle
Jack up the vehicle and place it on jack stands. Once more, lift by the frame, never by the axel. Choose a jack that can handle the weight of your trailer.
Most trailers weigh more than cars so your car jack may not work. A larger trailer may not need to be jacked up, but you will need to chock the tires. Chocking is when you use wedges of strong material and closely place them against the wheels. This will keep the trailer from moving.
3. Find brake chamber
You will find the brake chamber near the rear wheel. You will want to also find the pushrod. It comes out of the back of the chamber.
When the brake is pressed, the brake chamber goes back in. You might need someone to help you with this part. Have your helper push down on the brakes. You will be able to see the pushrod going in and out of the chamber when the brake is applied and released.
4. Find adjustment nut
In the back of the pushrod, you will find the adjustment nut. The nut will only turn freely in one direction. If you turn it the wrong way, it will ratchet. Turn it where it moves freely until the brake shoes are against the drum. At this point, the nut won’t turn anymore.
5. Turn nut
Once the nut doesn’t turn anymore, turn it in the other direction. You will hear the ratcheting. You will want to turn it one and a half turns.
6. Distance pushrod travels
The pushrod should travel between 1.25 and 1.5 inches into the chamber. Measure the distance. Your helper should press the brakes while you measure. The pushrod shouldn’t travel more than two inches.
7. When to call a mechanic
The pushrod shouldn’t travel more than two inches. If it does, it’s time to call a mechanic.
When to Manually Adjust Self-Adjusting Air Brakes
As self-adjusting air brakes acquire wear and tear, they will need adjusting. They will only self-adjust to a certain point. When they go beyond that point, they need manually adjusted.
When an air brake ages, the rubber in the brake chamber will stretch. It will become brittle. When this happens, it forces the brake arm to travel further to initiate the braking. The longer it takes the brake arm to engage the brakes the longer it will take to stop.
Surge Trailer Brakes
Surge brakes are also known as hydraulic surge brakes. They are generally used in:
- Boats
- Rentals
- Leisure trailers
With Surge trailer brakes, the driver doesn’t have to control them. They automatically activate when needed. The benefits of surge brakes include:
- No need to have knowledge of braking system
- Can be submerged in water
- Requires no electric controller
- Requires no special wiring
How to Adjust Surge Trailer Brakes
Brakes must be adjusted periodically in order to function properly. The steps include:
- Gather the tools needed
- Jack the trailer
- Locate the cover
- Insert flathead screwdriver
- Rotate tire
- Adjust star wheel
- Replace cover
- Repeat
1. Gather the tools needed
You will need a few tools to start. They include:
- Two wheel chocks
- Floor jack
- Jack stands
- Flathead screwdriver
2. Jack the trailer
Chock tires on the opposite side of the trailer you will be working on. Jack the side you will be working on until the tires rotate freely. Place jack stands.
3. Locate covers
Locate the cover that is over the adjustment hole. You will find it on the rearmost wheel. It will be on the backside of the brake backing plate. Take the cover off using your flat blade screwdriver. Save it.
4. Insert flat blade screwdriver
Insert the screwdriver in the exposed hole. You will come in contact with the star wheel. It will be used to adjust the brakes.
5. Rotate tire
Rotate the tire forward. While rotating the tire, use the screwdriver to turn the star wheel. It should turn in a clockwise direction. Do this until braking pressure or friction is felt on the wheel.
6. Adjust star wheel
Click star wheel five notches. Rotate the tire freely in a forward direction. Make sure it’s turning easily. Then you can remove the screwdriver.
7. Replace cover
Push the cover back in place and lower trailer
8. Repeat
Do the same procedure on the other side of the trailer.
Do You Need Trailer Brakes?
The majority of states require trailer brakes based on the trailer’s weight. A trailer with a gross weight of three thousand pounds or more is usually required to have brakes. But some experts recommend brakes for a trailer weighing fifteen hundred gross pounds or more.
Greasing Your Wheel Bearings
While you have your trailer jacked up, you should consider greasing those wheel bearings. A wheel bearing properly packed with fresh grease will rotate freely. And it will diminish overheating.
Wheel bearings secure the wheel and the tire to the trailer. It’s an easy process to repack your bearings. However, it is messy, so wear old clothes and wear latex gloves. Here are the steps.
- Gather the tools needed
- Jack up trailer
- Remove metal hub dust cover
- Remove dust jacket
- Grease gun
- Spin wheel
- Start pumping grease
- Scrape edges
- Put grease in a jar
- Avoid trailer brakes
- Insert Dust jacket
- Wipe
- Metal hub dust cover
1. Gather the tools needed
There are several tools needed to grease the wheel bearings. Most of them for clean-up. They include:
- Latex gloves
- Rags/paper towels
- Flat painter’s stick or tongue depressors
- Safety glasses
- Flathead screwdriver
- Grease gun
- 1 tube grease per wheel
- Sealable jar (like a peanut butter jar)
- Jacks
- Jack stands
- Chocks
2. Jack up trailer
You probably already have your trailer jacked up. But you do want to make sure the wheel you’re working on can spin freely.
3. Remove metal hub dust cover
There’s usually a little notch on the cover. Place your screwdriver in the notch and pry the cover off.
4. Remove dust jacket
There’s a little rubber dust jacket in the center. That covers the grease zerk. Put your screwdriver underneath it and pry it loose. If it’s dried and cracked, you’ll need to replace it.
5. Grease gun
Put on your latex gloves and safety glasses. Hook up your grease gun.
6. Spin wheel
Spin the wheel that you are working on and attach the grease gun.
7. Start pumping grease
New grease will go in and push the old grease out. You only want fresh grease. You don’t want a mixture of the old and new. That’s why you will use one tube of grease per wheel. The pressure of the gun will push the old grease out.
8. Scrape edges
Take the flat painter’s sticks or tongue depressors and scrape the old grease that is coming out. It will be oozing out of the zerk.
9. Put grease in a jar
Take the excess grease from the zerk and place it in your glass jar. The grease can be recycled.
10. Avoid trailer brakes
You don’t want to have any grease on your trailer brakes. Make sure you are careful. Take the towels or paper towels and constantly wipe them.
11. Insert dust jacket
Return the rubber dust jacket to its original position. Place the jacket in the hole by pushing in the center.
12. Wipe
Once, more and this can’t be stressed enough; you must wipe all the grease off. You don’t want to have grease on your brakes. Take the time to clean everything up.
13. Metal hub dust cover
Replace the metal hub dust cover, and you’re finished with the first one.
Check Your Trailer’s Tire Pressure
Finally, check to make sure all the tires have an ample amount of air. Now you’re ready to go.
