Tips and Tidbits

Identifying and Troubleshooting Electric Trailer Brakes

Identifying and Troubleshooting Electric Trailer Brakes

Chances are your Trailer is equipped with brakes, and just like the brakes on your Tow Rig, your trailers brakes need some maintenance from time to time. When it comes to servicing your trailers brakes, and getting the right parts that fit your application, there are a few key points to consider that will ensure you can properly identify your brakes, as well as some tips as to why your brakes may not be functioning properly.

  • Identifying Electric Brakes
  1. Right or Left: With the magnet positioned at the bottom of the brake, the actuating arm will start at the "Top Pivot" and curve downward towards the "Magnet". Arms curving Left, are left hand assemblies, where as arms curving Right, are right hand assemblies.
  2. Size: Measure the diameter of the mounted shoe assemblies across the front center, then measure the width of the shoe lining. This will give you your brakes size.
  3. Flange Mount: Determine the number of mounting bolts on your brake by counting the mounting holes, or studs on your brakes assembly.
  4. Replacement Parts: Sometimes a brakes functions can be restored by replacing a key component. Where as in some cases it may be cost effective to replace the entire brake assembly. Here is a list of the common replaceable parts. 
    • (1) Magnet 
    • (2) Return Springs 
    • (2) Hold Down Springs
    • (2) Show linings Primary, and secondary
    • (1) Adjuster
    • (1) Adjuster Spring 

  • Troubleshooting Faulty Brakes: 
    • Magnets: The first and  most common sign of a faulty magnet is erratic Brake Control Behavior. Magnets control the intensity of the brakes by grabbing the inside face of your brake drum, engaging the brake shoes. Magnets should be checked for exposed windings, and pinched or frayed wires. The face of the magnet also reflects the  inside surface of your brake drum. In order for the magnet to "grab" the drums surface, both surfaces must be alike. For example; A new magnets surface will be flat, where as the drums inside face may not be flat, creating less "grabbing surface" for the magnet, and weaker brakes. 
    • Brake Adjustment: In order for your brakes to operate as they should, they must be adjusted from time to time. Even self adjusting brakes fail to properly adjust themselves if key components begin to wear. Start by manually turning the Adjuster until you cannot turn the wheel, then back off the adjuster until the wheel is able to spin freely. A properly adjusted brake will have a Slight Constant Drag on the shoes. 
    • Adjuster & Spring: The Adjuster is located below the magnet, and should be "turn-able" but also under constant pressure from the Adjuster spring. A worn out Adjuster is unusual, but they are prone to freezing or seizing up. Sometimes you can hear them "rolling around" inside your hub/Drum assembly, this is a sign the adjuster was maxed out, or the spring is broken.  A maxed out adjuster can also mean your brakes are ready for new Shoes and Linings. ( If your shoes and linings are not worn out, and the Adjuster is maxed out: you need to check your Hold Down Springs, or check the drums inside bore diameter to ensure it is within maximum re-bore spec's which is located on inner lip of the brake drum )
    • Return & Hold Down Springs: Common signs of worn or weak springs inside your brakes are: Heat, Brake Drag, or "stinky Brakes". When a Return Spring becomes weak or fails, the shoes may not retract or may become stuck, generating excessive heat or causing brake failure. Hold Down Springs keep your brake linings aligned and centered, as well as mounted on the brake backing plate assembly. Worn out hold down springs will cause premature brake failure.
    • Shoes and Linings: Shoes and linings should wear even throughout the entire assembly. Irregular wear on the linings can usually be corrected by properly adjusting the brakes, and ensuring the return springs are properly functioning.
    • Check out Our Selection of Brake Parts! As it grows everyday!

Steps to Identify and Measure a Trailer Leaf Spring

Step 1: Determine Type of Trailer Spring 

Determine the type of trailer spring. What do the ends of your trailer spring look like? Below are images of the most common types of trailer springs.  You will need to know  if you have a double eye spring or a slipper spring with a flat, radius, open eye, or hook end.

Step 2: Measure Width of Spring 

Measure the width of the spring. The majority of trailer springs for boat, motorcycle, horse, camping, flatbed, and utility trailers range from 1-3/4 to 2 inches wide.  To determine the width, measure across the top of the top leaf.

 

Step 3: Measure Length of Spring 

Measure the length of the spring. If you are replacing a spring, getting the same length is important. To measure the free length, refer to letter “C” below. It is important that your trailer is unloaded when measuring the length. When determining length (C), measure from the center of one spring eye to the center of the other spring eye for double eye springs. Measurements will vary depending on the age and fatigue of your spring. We offer a large selection of trailer springs. Determining the length first, will narrow your selection down considerably and make finding the correct spring quicker.

Step 4: Determine Capacity 

Determine the capacity and how many leafs. Determine what type of capacity you require and how many steel leaves your existing springs have. If you are replacing all of your springs, the number of leafs will not be as important. You can switch from a 4 leaf to a 3 leaf with thicker steel if you prefer. The capacity ratings are per spring. Determine the rating of your trailer axle and then select the capacity of your springs. If you have a 6000 lb. rated trailer axle with two springs, use two 3000 lb. rated or higher trailer springs.

 

Step 5: Measure Free Open and Arc of the Spring 

Measure the free open (H) and the arc (A) and (B) of the trailer spring. These measurements are more for reference and will change with the age and fatigue of your spring. These measurements can show you the importance of replacing all of your springs rather than one at a time. If you have an older spring that has lost its arc over time and you add one new spring with a taller arc to the other side of your trailer, your trailer will lean to one side causing for an uneven load and unsafe conditions.

Trailer Spring Capacity 

The capacity rating is per spring. If you have a 6000 lb. rated trailer axle with two springs, use two 3000 lb. rated springs.

 

Change Springs in Pairs 

All springs are sold individually, but it is highly recommended to change them in pairs. Changing only one spring may cause your trailer to lean to one side due to the spring fatigue of the unchanged spring(s) and can cause excessive tire wear.

 

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