Keep Your Wagon from Saggin’

| August 31, 2001

It is not uncommon for trailers that are well-maintained to provide dependable service for 25 years or more. That requires a preventive maintenance program suited to your type of trucking, and regular checks of the running gear, lighting, cargo securement fixtures, doors and other components for physical damage and signs of small problems that could grow into big, expensive ones on the road.

The trucking industry’s long-term objective is a 10-year maintenance-free trailer, according to Meritor Heavy Vehicle Systems. Transcraft, Wabash and many other trailer makers are able to offer longer warranties because component manufacturers are developing products that extend maintenance intervals. One such product is a unitized wheel end that eliminates seal leaks and the damage oil does to brake linings – a major trailer maintenance problem.

Keeping your trailer’s brakes in peak operating condition, so that each one does part of the braking, is the best way to minimize stopping distances and avoid penalties during roadside inspections. S-cam brakes and automatic slack adjusters should be lubricated according to the manufacturers’ recommended service interval.

Listen for air leaks in the brake system, and check to see that air lines are not damaged. Check for cracked drums, missing or broken shoes, and shoes soaked with grease, brake fluid or oil. Also, keep an eye open for damaged brake chambers and replace them as needed. Glad hands and rubber seals should be checked for signs of damage and wear.

Brake shoes should be relined or replaced with remanufactured shoes when they wear down to 1/4-inch at their thinnest point. Linings should be replaced on both sides of an axle at the same time to avoid brake pull. Shoe return springs should also be replaced when you reline.

Brake drums should be inspected periodically for damage and excessive wear. Drums can be resurfaced to remove shallow grooves and moderate heat checking, but look for the cause of the damage and correct the root problem before you remount. Drums with deep, wide cracks should be replaced.

Suspension trouble signs
Whether you pull a van or flatbed, the most important item to inspect regularly is the suspension, according to Great Dane Trailers. The suspension is most prone to failure if it’s not properly maintained, says the trailer manufacturer. Suspension problems are the second most common category of defects cited by roadside inspectors, after brakes.

Signs of misaligned, shifted, cracked or missing springs; loose or missing shackles and bolts; spring hangers unsecured at the frame; and cracked or loose U-bolts can all put your rig out of service in an inspection. Spring packs with 25 percent or more of the leaves broken should be replaced to avoid the possibility of an out-of-service citation during a roadside inspection.

A good rule of thumb is to perform regular trailer maintenance checks every six months or 15,000 miles, although some items, such as wheels, should be checked every 2,000 to 3,000 miles, advises Great Dane. The company recommends the following schedule:

  • Every 25,000 to 30,000 miles, check for brake lining wear; inspect the camshafts, camshaft spider bushings and camshaft support bracket bushing for signs of wear; and lubricate brake actuating components.
  • Every 100,000 miles, once a year, or at brake reline, replace the wheel bearing lube oil; check brake air chambers and slack adjusters; and inspect brake rollers, roller shafts, anchor pins and bushings, and replace if necessary.
  • Proper lubrication is essential to prolong the life of any trailer. Keep the landing gear and doors lubed to ensure smooth operation. Metal suspension components require lubrication and retorquing at regular intervals to prolong their life and help your suspension operate at peak performance.
  • Hit all zerk fittings with your grease gun. Bronze bushings should be lubricated, but rubber bushings should not, since lubricants can damage them. Keep lubricants away from rubber blocks and other rubber suspension components, too.
  • Sliding tandem axles are subjected to extreme stress, and they should be checked regularly for damage. Periodic lubrication of the pin release mechanism reduces the effort needed to pull the handle and helps prevent lock pins from binding. The slider’s components should be lubed according to the manufacturer’s guidelines.
  • Check the slider box for deformation and fractures. Indexing holes can become worn or elongated, so watch them. Washing out the frame to avoid carrying around a load of road salt or dirt inside it is also a good idea.

Most air suspension failures can be traced to a lack of preventive maintenance or improper application. The correct ride height should be maintained within 1/4-inch of the OEM’s established height. Leveling valves should be cleaned, inspected and replaced if malfunctioning.

On trailers with air ride suspensions, Firestone Industrial Products Co., which manufactures Airide air springs, recommends periodic checks to detect:

Keep Your Wagon from Saggin'

| August 31, 2001

It is not uncommon for trailers that are well-maintained to provide dependable service for 25 years or more. That requires a preventive maintenance program suited to your type of trucking, and regular checks of the running gear, lighting, cargo securement fixtures, doors and other components for physical damage and signs of small problems that could grow into big, expensive ones on the road.

The trucking industry’s long-term objective is a 10-year maintenance-free trailer, according to Meritor Heavy Vehicle Systems. Transcraft, Wabash and many other trailer makers are able to offer longer warranties because component manufacturers are developing products that extend maintenance intervals. One such product is a unitized wheel end that eliminates seal leaks and the damage oil does to brake linings – a major trailer maintenance problem.

Keeping your trailer’s brakes in peak operating condition, so that each one does part of the braking, is the best way to minimize stopping distances and avoid penalties during roadside inspections. S-cam brakes and automatic slack adjusters should be lubricated according to the manufacturers’ recommended service interval.

Listen for air leaks in the brake system, and check to see that air lines are not damaged. Check for cracked drums, missing or broken shoes, and shoes soaked with grease, brake fluid or oil. Also, keep an eye open for damaged brake chambers and replace them as needed. Glad hands and rubber seals should be checked for signs of damage and wear.

Brake shoes should be relined or replaced with remanufactured shoes when they wear down to 1/4-inch at their thinnest point. Linings should be replaced on both sides of an axle at the same time to avoid brake pull. Shoe return springs should also be replaced when you reline.

Brake drums should be inspected periodically for damage and excessive wear. Drums can be resurfaced to remove shallow grooves and moderate heat checking, but look for the cause of the damage and correct the root problem before you remount. Drums with deep, wide cracks should be replaced.

Suspension trouble signs
Whether you pull a van or flatbed, the most important item to inspect regularly is the suspension, according to Great Dane Trailers. The suspension is most prone to failure if it’s not properly maintained, says the trailer manufacturer. Suspension problems are the second most common category of defects cited by roadside inspectors, after brakes.

Signs of misaligned, shifted, cracked or missing springs; loose or missing shackles and bolts; spring hangers unsecured at the frame; and cracked or loose U-bolts can all put your rig out of service in an inspection. Spring packs with 25 percent or more of the leaves broken should be replaced to avoid the possibility of an out-of-service citation during a roadside inspection.

A good rule of thumb is to perform regular trailer maintenance checks every six months or 15,000 miles, although some items, such as wheels, should be checked every 2,000 to 3,000 miles, advises Great Dane. The company recommends the following schedule:

  • Every 25,000 to 30,000 miles, check for brake lining wear; inspect the camshafts, camshaft spider bushings and camshaft support bracket bushing for signs of wear; and lubricate brake actuating components.
  • Every 100,000 miles, once a year, or at brake reline, replace the wheel bearing lube oil; check brake air chambers and slack adjusters; and inspect brake rollers, roller shafts, anchor pins and bushings, and replace if necessary.
  • Proper lubrication is essential to prolong the life of any trailer. Keep the landing gear and doors lubed to ensure smooth operation. Metal suspension components require lubrication and retorquing at regular intervals to prolong their life and help your suspension operate at peak performance.
  • Hit all zerk fittings with your grease gun. Bronze bushings should be lubricated, but rubber bushings should not, since lubricants can damage them. Keep lubricants away from rubber blocks and other rubber suspension components, too.
  • Sliding tandem axles are subjected to extreme stress, and they should be checked regularly for damage. Periodic lubrication of the pin release mechanism reduces the effort needed to pull the handle and helps prevent lock pins from binding. The slider’s components should be lubed according to the manufacturer’s guidelines.
  • Check the slider box for deformation and fractures. Indexing holes can become worn or elongated, so watch them. Washing out the frame to avoid carrying around a load of road salt or dirt inside it is also a good idea.

Most air suspension failures can be traced to a lack of preventive maintenance or improper application. The correct ride height should be maintained within 1/4-inch of the OEM’s established height. Leveling valves should be cleaned, inspected and replaced if malfunctioning.

On trailers with air ride suspensions, Firestone Industrial Products Co., which manufactures Airide air springs, recommends periodic checks to detect:

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