The 1973 Plymouth Scamp is essentially a rebadged Dodge Dart with Plymouth trim, riding on Chrysler's robust A-body platform. These are mechanically straightforward cars with proven slant-six and LA-series V8 engines, but age-related issues now dominate given all examples are 50+ years old.
Timing Chain Wear and Failure (Slant-Six and 318/340 V8)
Common · high severityTypical onset: 80,000-150,000 mi
Symptoms: Rattling or slapping noise from front of engine at cold start that fades when warm, Difficulty starting, backfiring through carburetor, Loss of power, poor idle quality, Check timing with light—retarded 10-15 degrees indicates stretched chain
Fix: Replace timing chain, gears, and tensioner. On slant-six this is a 3-4 hour job with radiator removal. V8s take 4-5 hours due to tighter engine bay. Must set timing after installation. Original single-roller chains rarely lasted beyond 100k; double-roller kits are the fix.
Estimated cost: $400-800
Torsion Bar Anchor Corrosion and Failure
Common · high severitySymptoms: One front corner sitting noticeably lower than the other, Clunking from front suspension over bumps, Visible rust-through or cracking at lower control arm hex sockets, Torsion bar adjuster bolt spinning without effect
Fix: The hex pockets in the lower control arms rust out from road salt and trap moisture. Requires replacement lower control arms (originals NLA, aftermarket available) and possibly new torsion bars. 4-6 hours per side with alignment required. Inspect carefully before purchase—this is frame/subframe work.
Estimated cost: $800-1,500
Floor Pan and Torque Box Rust-Through
Common · medium severitySymptoms: Visible holes in driver/passenger floor pans, Rust perforations in rear torque boxes behind rear wheels, Carpet wet after rain or car wash, Spongy feeling when jacking at rocker panels
Fix: Floor pans rust from inside out due to trapped moisture. Torque boxes (structural shock mounts) rust from leaves/debris in trunk. Patch panels available but require cutting and welding. 8-12 hours labor for floor pans, 6-8 for torque boxes. This is bodywork, not mechanical—get a welder involved.
Estimated cost: $1,200-3,000
Single-Pot Master Cylinder Failure
Occasional · high severitySymptoms: Complete brake pedal loss without warning, Brake fluid leak from rear of master cylinder, Spongy pedal that goes to floor
Fix: 1973 was last year for single-reservoir master cylinders before dual split systems became mandatory. When the single seal fails, you lose ALL brakes. Upgrade to later A-body dual-reservoir master (1974-76 Dart/Scamp) is bolt-on and highly recommended. 2 hours including bench-bleeding and system bleed.
Estimated cost: $250-450
Upper Control Arm Bushing Deterioration
Common · medium severitySymptoms: Steering wander, car darts left or right on bumps, Clunking over railroad tracks, Uneven tire wear on inside edges, Visible cracking or missing rubber in upper control arm pivot bushings
Fix: Original rubber bushings harden and crack after decades. Requires pressing out old bushings, pressing in new (polyurethane recommended for longevity). 3-4 hours labor plus alignment. Ball joints should be inspected simultaneously—often worn on high-mileage examples.
Estimated cost: $500-900
Carburetor Fuel Percolation and Vapor Lock
Occasional · medium severitySymptoms: Hot-start difficulty after short drives in warm weather, Engine dies at stoplights when heat-soaked, restarts after cooling, Fuel smell from engine bay after shutdown, Hesitation and stumbling immediately after hot restart
Fix: Carter BBD (slant-six) and Holley/Carter (V8) carburetors sit directly over exhaust crossover on intake manifold. Modern fuel formulations vaporize easier. Solutions: heat-shield gaskets under carb (1 hour), electric fuel pump to maintain pressure (2-3 hours), or insulated fuel line. Carburetor rebuild if floats are sticking adds 4 hours.
Estimated cost: $200-600
Steering Box Play and Leakage
Common · medium severityTypical onset: 100,000+ mi
Symptoms: Excessive play at steering wheel (more than 2 inches at rim), Power steering fluid leak from sector shaft seal, Groaning noise when turning at low speed, Wandering straight-line tracking requiring constant correction
Fix: Manual and power steering boxes wear at sector shaft and develop leaks. Adjustable via screw on top but only takes up so much slack. Rebuilt boxes available but core charge applies. 3-4 hours to R&R, includes alignment. Manual boxes last longer; power boxes leak more often.
Estimated cost: $450-850
Buy one if rust-free and mechanically documented; avoid if floor pans or suspension mounts are compromised—repair costs will exceed purchase price quickly on a $5k-$8k 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.