Service Schedule

Regular trailer maintenance is critical to ensuring the longevity of your trailer, as well as making sure you are able to tow to your destination safely. Before towing, make sure your trailer and its many components are in safe working order. Worn or broken trailer parts can cause loss of control and injury may result. After any accident or impact, it is important to have your trailer professionally inspected.

You must inspect, maintain and service your trailer regularly to insure safe and reliable operation. If you cannot or are unsure how to perform the items listed here, have your dealer do them.

Note: In addition to this information, also check your trailer’s owner’s manual and the relevant component manufacturer’s manuals. Where discrepancies may exist, defer to the manufacturer's manual. 

What follows is a recommendation for minimum maintenance. However, depending on the trailer usage, including cargo weight and mileage, as well as the environmental factors where the trailer is in use, your trailer may need more regular maintenance than that which is described below.

Properly functioning brake shoes and drums are essential to ensure safety. You must have your dealer inspect these components at least once per year, or each 12,000 miles. Brake adjustment is not covered under the axle warranty.

The brake shoes must be adjusted after the first 200 miles of use, and each 3,000 miles thereafter. Most axles are fitted with a brake mechanism that will automatically adjust the brake shoes when the trailer is “hard braked” from a rearward direction.

Note: Trailer disc brakes are self-adjusting and do not need to be periodically adjusted.

Using pads or shoes without enough brake lining material can result in brake damage, create excessive heat and potentially cause the loss of braking capacity. Read your axle and brake manual to see how to adjust your brakes. If you do not have this manual, contact your dealer for assistance.

Brake Shoes – Properly functioning brake shoes are essential to trailer safety. To inspect brake shoe lining, remove hub. Once the hub is removed and before you start any service or inspection, clean the brake assembly with brake system cleaner and allow it to dry. Never use compressed air or a brush to remove dust.

• Inspect both leading and trailing brake shoe lining for excessive wear. Hairline heat cracks are normal; however, if the lining is worn more than 1/16th inch, corroded, damaged or contaminated with grease or oil, replace the brake shoes.
• Replace brake shoes per the manufacturer’s owner’s manual. Otherwise, reassemble the hub and manually adjust the brake shoe.
• Note: If replacing brake shoes on one wheel, the opposite wheel should also be replaced. Whenever brake shoes are replaced, the retracting and hold-down springs should also be replaced.

Electric Brakes

Electric brakes are actuated by an electromagnet, which grabs the armature surface of the hub when a small current is applied. The current is received by either the tow vehicle or a breakaway battery. When the trailer brakes are operated by the tow vehicle, it is important they are “synchronized” so braking is properly distributed to both the tow vehicle and the trailer. Synchronization is accomplished by adjusting the gain on the tow vehicle controller. With the tow vehicle hooked up to the trailer, make several hard stops on dry pavement. If the trailer’s brakes skid or are too sensitive, decrease the gain on the brake controller. If they do not skid, slightly increase the gain setting. Remember, this gain setting is load sensitive. Readjust the gain if the trailer’s load changes.

• Inspect for any loose or worn parts including stretched or deformed springs in the brake assembly. Replace if needed.
• Inspect the electromagnets for uneven or abnormal wear. Use a small straight edge to check for even wear. If worn, or the magnet coil has become visible, replace the magnet.
• Note: It is recommended the hub armature surface be turned when magnets are replaced. Magnets should be replaced in pairs. If you change a magnet on one hub, the opposite magnet should also be replaced.
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Breakaway Brake Battery

This battery supplies a current to operate the trailer brakes, if the trailer breaks away from the tow vehicle. Check the battery for proper power level.

Hydraulic/Surge Brakes

Hydraulic or surge brakes are among the most common braking system used on trailers in the rental industry. Unlike electric brakes, they do not require any special device or controller in the tow vehicle.  

Surge brakes are activated by the stopping inertia created between the tow vehicle and the trailer. When the tow vehicle reduces speed, pressure is applied to an actuating coupler on the trailer. The pressure forces hydraulic fluid from a master cylinder in the actuator coupler, through hydraulic lines, to a wheel cylinder which, in turn, applies force against the brake shoes and hub.

Because surge breaks are a self-contained systems, upkeep is vital to safe and reliable operation. The key to a successful and lasting operation of the surge brake unit is to keep the master cylinder free of contamination, and always maintain proper levels of brake fluid.

• Inspect the wheel cylinder for leaks and proper operation. Clean with brake cleaner only. Use fresh brake fluid to flush the cylinder. Repair or replace if needed.
• Inspect the brake lines for kinks, cracks or breaks. Clean lines to check for fresh leaks. Repair or replace as necessary. Use fresh brake fluid to flush lines. Bleed system, if needed, to remove all air.
  
  • Block tires if working with trailer on the ground. Otherwise, jack up the trailer and secure it on adequate capacity jack stands. Follow trailer manufacturer's recommendations for lifting and supporting the trailer Ensure the hydraulic surge brake coupler is fully extended, relieving any pressure on the brake shoes.
  • Fill master cylinder with fluid. Install a bleeder hose (clear if available) on first wheel cylinder to be bled (if tandem axle trailer, bleed rear axle first). Submerge loose end of hose in a clear container of brake fluid to observe bubbling.
  • Loosen the bleeder screw, located in the wheel cylinder one half turn. The system will be open to the atmosphere through the passage drilled in the screw. Pump actuator one full stroke and hold (using breakaway level or coupler). Now, close the bleeder valve and release the lever. After the lever is back, open the bleeder valve, pull the lever forward and hold. This process must be repeated until bubbles stop coming out of the hose in the clear container. Be sure to close bleeder screw securely.
  • Repeat bleeding operation at each wheel cylinder. During the bleeding process, replenish the brake fluid so the level does not fall below the half full level in the master cylinder reservoir. After bleeding is complete, fill the master cylinder reservoir and secure the filler cap.
  • After the bleeding operation is complete, apply pressure to the system and check the brake system for leaks.
• Inspect for any loose or worn parts, including stretched or deformed springs in the brake assembly. Replace if needed.
• Inspect inner slide for bowing or indention at rollers. Excessive weight or heavy use may bend the inner slide mechanism at the roller location, when in normal operation. This may not allow the inner slide to move freely and apply proper force to the master cylinder for adequate braking.
• Inspect the master cylinder for proper fluid level. Use only DOT-3 or DOT-4 brake fluid from a sealed container. Improper fluid level is one of the most common causes of hydraulic brake failure, while the most easy to prevent. If the fluid gets too low or goes empty, you will have to bleed the complete brake fluid system. This is no easy task and may never have to be done under normal operating conditions. Refer to the manufacturer’s owner’s manual for fluid requirements.
• If you find or see brake fluid leaks, they should be attended to immediately. Check the surge brake master cylinder for proper brake fluid levels to avoid having to bleed the entire system.

•  Check to see if the trailer alignment is correct
• Inspect axle welds and joints
• Inspect for damage on the spindle where it is welded to the axle tube
• Bent axles or spindles cause excess tire wear, and potentially increases sway and whipping during towing.

•  Inspect all fasteners, bolts, nuts, screws, rivets and structural frame members for bending and other damage, cracks, or failure at least once a year.
• Repair or replace any damaged fastener and repair the frame member.
• If you have any questions about the condition or method of repair of fasteners or frame members, get the recommendation of, or have the repair done by your dealer.

NOTE: Broken or damaged fasteners can cause injury or damage to trailer and contents. 

All welds can crack or fail when subjected to heavy loads or movement of cargo that was not properly secured. Any time that you know or suspect that the trailer has been subjected to heavy loads or movement of cargo, immediately inspect the welds and fasteners for damage. To prevent severe damage to your trailer, inspect all of the welds for cracks or failure at least once a year.

If you find a crack it should NOT be welded over. The crack needs to be properly repaired to ensure the structural integrity of the trailer. If a weld failure is detected, contact your dealer.

Most frame and structure failure are a result of too much load for the material of the trailer. The two areas which should be closely checked for fatigue or stress is (1) all points where the tongue attaches to the trailer; and (2) where the spring hangers are welded to the trailer frame.

A good indicator of cracks, stress or fatigue can be rust. If you see rust occurring it warrants closer inspection.

Always inspect lights before each use. Repair or replace as needed.

• Inspect connectors for rust, corrosion, or other defects.
• Inspect wire for pinches, kinks, or exposed bare wire. If repairs, or welding, have been done on the trailer, look for burned or scorched wires. Ensure bare wires do not contact metal from the trailer. This may cause the electrical system to short, blow fuses or possibly cause electrical fire.
• Make sure connector-plug prongs and receptacles, light bulb sockets, wire splices and ground connections are clean and shielded from moisture.
• Lightly coat all electrical terminal connections with nonconducting (dielectric), light waterproof grease.
• Clean the prongs with very fine sandpaper, being careful not to damage the contact area.
• Clean the surface deposits in the connector holes. (Make sure the lights are off to prevent blowing a fuse.) Try to clean off only the deposits and lubricate lightly with dielectric, light waterproof grease.