The 1966 Plymouth Belvedere is a solid B-body Mopar with decent build quality for its era, but suffers from typical 1960s issues: primitive drum brakes, torsion bar wear, and deteriorating steering/suspension components that compromise safety at highway speeds.
Torsion Bar Sagging and Anchor Failure
Common · medium severitySymptoms: Front end rides low on one or both sides, Uneven tire wear, Clunking from lower control arm area, Wandering steering feel
Fix: Torsion bars lose tension over decades, and the anchors corrode or crack. Replacement requires unloading bars (tricky without proper tools), replacing anchors, adjusting ride height. 3-5 hours labor depending on rust.
Estimated cost: $400-800
Steering Box Slop and Pitman Arm Wear
Common · high severityTypical onset: 80,000+ mi or age-related
Symptoms: Excessive play at steering wheel (more than 2 inches), Wandering at highway speeds, Clunking when changing direction, Loose feel in center position
Fix: Manual steering boxes wear internally; rebuild kits available but often easier to source reman unit. Pitman arm and idler arm bushings also fail. Plan 4-6 hours for steering box R&R, alignment, and front-end inspection.
Estimated cost: $600-1,200
Timing Chain Stretch (273/318/383 V8s)
Common · medium severityTypical onset: 60,000-100,000 mi
Symptoms: Rattling from timing cover at cold start, Erratic idle, Backfiring through carb, Loss of power, poor fuel economy, Check timing with light — jumps around
Fix: Original single-row chains stretch, retarding cam timing. Requires timing cover removal, new chain/gear set, oil pan gasket often weeps so replace while you're there. 4-6 hours labor, more if accessories/power steering complicate access.
Estimated cost: $500-900
Single-Circuit Brake System Failure
Occasional · high severitySymptoms: Pedal goes to floor with no warning, Brake fluid leak anywhere = total loss, Rear wheel cylinders seeping, Soft pedal, long stopping distances
Fix: Pre-1967 single-circuit master cylinder means one leak kills all brakes. Wheel cylinders, hard lines, and flex hoses all rot. Recommend dual-reservoir master conversion (requires new proportioning valve, lines). Full system overhaul: 8-12 hours.
Estimated cost: $1,200-2,000
Carter AFB/AVS Carburetor Flooding and Bogging
Common · low severitySymptoms: Rich fuel smell, black smoke, Hesitation on acceleration, Hard starting when hot, Fuel leaking from carb base or bowl, Stalling at idle
Fix: Original Carter carbs have old gaskets, worn throttle shafts, stuck floats. Rebuild kits run $50-80; proper rebuild takes 2-3 hours if you know what you're doing. Alternatively, swap to Edelbrock Performer ($300) for reliability.
Estimated cost: $150-500
Lower Ball Joint Wear
Common · high severityTypical onset: 70,000-120,000 mi
Symptoms: Clunking over bumps, Tire cupping on inside edge, Steering shimmy, Visible play when prying on tire with bar
Fix: Load-bearing lower ball joints wear out, especially if grease fittings were neglected. Screw-in style makes replacement straightforward but requires press or ball joint tool. Replace both sides, align. 3-4 hours labor.
Estimated cost: $350-650
Rear Leaf Spring Shackle Bushings and Sagging
Occasional · low severitySymptoms: Rear axle sits low or cocked to one side, Clunking over bumps from rear, U-bolts loose, spring perches shifted, Harsh ride quality
Fix: Rubber shackle bushings dry-rot, springs lose arch over 50+ years. Polyurethane bushings recommended for longevity. Spring replacement or re-arching adds cost. 3-5 hours labor.
Estimated cost: $400-900
Electrical Gremlins: Ammeter Gauge and Bulkhead Connector
Occasional · medium severitySymptoms: Ammeter pegged or flickering, Smell of burning plastic near firewall, Intermittent no-start, no gauges, Headlights dim at idle, Melted bulkhead connector terminals
Fix: High current through ammeter and bulkhead connector causes heat, corrosion, eventual failure or fire risk. Bypass ammeter with voltmeter, clean/re-pin bulkhead, upgrade alternator wiring. 2-4 hours labor if you catch it early.
Estimated cost: $200-600
Buy one if you're handy and want a straightforward classic — parts are available and most repairs are DIY-friendly, but budget for front-end and brake work immediately.
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.