The 1972 Plymouth Duster is a robust A-body platform with simple Slant-Six or small-block V8 power. Most problems stem from age-related deterioration rather than design flaws, but critical wear points exist in the front suspension, steering box, and ignition systems.
Timing Chain Stretch and Sprocket Wear (V8s)
Common · medium severityTypical onset: 80,000-120,000 mi
Symptoms: Rough idle with inconsistent timing adjustments, Backfiring through carburetor on acceleration, Engine won't start after sitting, but cranks fine, Rattling from timing cover on cold starts
Fix: Replace timing chain, sprockets, and front seal with quality double-roller set. Requires front accessory removal and harmonic balancer puller. 4-6 hours labor for experienced tech, more if you're fighting seized balancer bolt.
Estimated cost: $400-750
Torsion Bar Anchor Corrosion and Suspension Sag
Common · medium severitySymptoms: Front end sits significantly lower than rear, uneven ride height side-to-side, Clunking from lower control arm area over bumps, Excessive nose-dive during braking, Visible rust perforation in torsion bar crossmember
Fix: Crossmember rust often prevents proper adjustment. Clean threads and re-index torsion bars first. If crossmember is compromised, welded reinforcement or replacement required. Includes alignment afterward. 3-5 hours for adjustment and cleanup, 8-12 hours if welding structural rust.
Estimated cost: $350-1,200
Steering Box Wear and Sector Shaft Slop
Common · high severityTypical onset: 70,000-110,000 mi
Symptoms: Excessive play at steering wheel, 2+ inches of dead zone, Wandering on highway requiring constant correction, Clunking felt through steering column when changing direction, Grease leaking from sector shaft seal
Fix: Manual steering boxes can be adjusted via sector shaft screw, but worn internals require rebuild or replacement. Power steering boxes typically need full replacement. Includes alignment. 2-3 hours for R&R, add 4-6 hours if rebuilding in-house.
Estimated cost: $450-950
Electronic Ignition Module Failure (If Converted)
Occasional · high severitySymptoms: Sudden stalling when engine reaches operating temperature, No-start condition with good spark initially, then nothing, Intermittent cutting out during driving that clears when cooled, Engine dies and restarts fine 20 minutes later
Fix: Original points systems are more common on '72s, but many have been converted to Mopar electronic. Heat-soaked control modules fail without warning. Replace module and ballast resistor together. 0.5-1 hour labor if diagnosed correctly.
Estimated cost: $120-220
Upper Control Arm Bushings and Ball Joints
Common · medium severityTypical onset: 60,000-100,000 mi
Symptoms: Tire wear on inside or outside edges despite alignment, Popping or creaking when turning at low speed, Shimmy or vibration at 45-55 mph that feels suspension-related, Visible separation or cracking in rubber bushings
Fix: Upper ball joints are riveted from factory, require drilling out and bolting in replacements. Bushings need press or torch persuasion. Do both sides simultaneously. Plan on alignment afterward. 4-5 hours for complete upper control arm overhaul both sides.
Estimated cost: $600-950
Carburetor Base Gasket Vacuum Leaks (All Engines)
Common · low severitySymptoms: High idle that won't adjust down properly, Hissing sound near carburetor when engine running, Stumble or hesitation on light throttle application, Engine dies when shifted into gear from neutral
Fix: Heat cycles cause base gaskets and intake manifold gaskets to fail. Carburetor removal and cleaning recommended while apart. Check intake manifold-to-head gaskets if issue persists. 1.5-2.5 hours depending on linkage complexity and stuck fasteners.
Estimated cost: $180-350
Rear Axle Bearing Noise and Seal Leakage
Occasional · medium severityTypical onset: 85,000-130,000 mi
Symptoms: Howling or droning from rear that increases with speed, Gear oil dripping from brake backing plates, Hot metal smell from rear axle after highway driving, Grinding sensation through floorboards during acceleration
Fix: 8.25" or 7.25" rear ends have tapered axle bearings that require periodic adjustment. Leaking seals contaminate brake shoes. Full axle bearing and seal replacement both sides recommended when one fails. 3-4 hours including brake cleaning and bleeding.
Estimated cost: $450-700
Floor Pan and Trunk Floor Rust-Through
Common · medium severitySymptoms: Visible daylight through floor under carpet or mat, Wet carpet after rain or car wash with no obvious leak path, Soft or spongy feeling when stepping near rocker panels, Trunk holds water like a bathtub after precipitation
Fix: Not mechanical but safety-critical. Drain plugs clog and trap water in rocker channels. Proper repair requires cutting out rust and welding in replacement panels. Patch jobs with fiberglass don't pass inspection in most states. 12-20 hours for professional rust repair depending on extent.
Estimated cost: $1,500-4,000
Buy one if the body is solid and front suspension hasn't been neglected—mechanicals are straightforward and parts availability remains excellent for a 50-year-old car.
AI-assisted summary drawn from NHTSA recall data, our labor-times database, and platform knowledge. Not a substitute for a pre-purchase inspection on a specific vehicle.