SIDEBAR: Why Springs Get Sprung

While air suspensions tend to last longer than steel springs assuming proper maintenance, nothing’s perfect. Here’s a list of the six most common causes of air-spring failure, adapted from material by air-suspension manufacturer The Triangle Group, Dubois, Pa.

1. Overextension. Symptom: Bellow is torn away from the bead plate or piston, with the bead plate bent or cracked around fitting. Cause: Air spring is operating outside maximum travel (a result of excessive axle travel, a defective or improperly adjusted height control valve, or a too-short air spring selected). Solution: Bring the air spring back into proper operating zone by limiting axle travel; checking leveling valve for proper operation; adjusting valve to proper ride height; and checking for proper application.

2. Abrasion. Symptom: Hole is cut or rubbed into the side of the bellow. Cause: Bellow contacts suspension parts due to underinflation, loose attaching parts (shocks, brackets, etc.), air-supply lines unrestrained, or wrong air spring (inflated diameter too large). Solution: Clear bellow of obstructions/contact by checking proper air supply; securing all surrounding parts to eliminate contact with bellow; strap air-supply lines away from the bellow; check for proper application.

3. Contamination. Symptoms: Air leaks, bulges in bellow, internal/external corrosion of metal parts. Cause: Faulty air compressors, separators, or air dryers; oil/grease from the vehicle or cargo; road debris like quarry dust, anti-skid, etc. Solution: Periodically check air-spring condition. Check for oil or water in air supply. Check seals, avoid excessive greasing, watch for spillage. Keep piston, girdle hoops, bead plate areas clean (soap and water; not petroleum-based solvents).

4. Suspension Misalignment. Symptoms: Bellow abrasion; tears or holes at girdle hoop; bead plates bent at frame-rail mounting. Cause: Air spring is not operating in proper alignment. Solution: Proper alignment of suspension; check bushing for wear; check for damaged, bent, or broken suspension components; check that suspension has been installed properly.

5. Road Hazards. Symptom: Sudden blow-out of bellow. Cause: Road hazards like stone or metal items puncture the spring. Solution: Difficult to control, but check yards, roads you’ll be driving over. Add protective items like stone guards, and check to ensure clear unload zone.

6. Fatigue/Old Age. Symptoms: Severe cracking of bellow, or cord showing. Cause: Everything wears out eventually. Solution: Check for wear in your PM schedule, and record expected life. Replace before a failed spring strands you.