1974 PLYMOUTH SCAMP

Typical onset: 80,000-150,000 mi

Symptoms: Rattling noise from front of engine on cold start that quiets after warmup, Loss of power and rough idle as chain stretches, No-start condition if chain jumps teeth or breaks, Check timing shows retarded position despite correct distributor setting

Fix: Replace timing chain, gears, and tensioner; requires front cover removal. On slant-six this means removing water pump, harmonic balancer, and oil slinger. Experienced tech needs 4-5 hours; DIY typically 6-8 hours due to seized bolts. Replace both cam and crank gears even if they look okay—nylon teeth on cam gear deteriorate.

Estimated cost: $400-800

Symptoms: Front end sags on one or both sides despite adjusting ride height, Clunking from front suspension over bumps, Visible rust perforation where torsion bar anchors into lower control arm, Uneven tire wear due to alignment issues from sagging

Fix: Lower control arm replacement required if anchor socket is corroded out—adjustment alone won't fix it. Must unload torsion bar (dangerous if not done correctly), remove ball joints, press out bushings. Northern/rust-belt cars often need both sides. 3-4 hours per side plus alignment. Some cars need frame rail reinforcement if rust has spread.

Estimated cost: $600-1,200 per side

Symptoms: Hard starting when hot, starts fine cold, Hesitation or stumble on acceleration, Black smoke from exhaust indicating rich condition, Fuel smell due to leaking accelerator pump diaphragm, Stalling at idle or when coming to stop

Fix: Carter BBD used on most engines; accelerator pump diaphragm and power valve failures are typical. Ethanol fuel destroys original gaskets and causes internal corrosion. Full rebuild kit with non-ethanol-compatible parts: 2-3 hours for experienced carb tech. Many owners opt for aftermarket Edelbrock replacement ($300) for reliability. Core exchange rebuilds available but quality varies.

Estimated cost: $250-500 rebuild, $450-650 replacement

Typical onset: 100,000-180,000 mi

Symptoms: Excessive play at steering wheel—more than 2 inches of free movement, Power steering fluid leaking from sector shaft seal, Wandering on highway requiring constant correction, Groaning noise when turning at low speeds

Fix: Chrysler manual steering boxes last forever; power steering boxes develop sector shaft seal leaks and internal wear. Adjustment helps temporarily but worn boxes need rebuilding or replacement. Remove pitman arm (requires puller), disconnect steering column coupler, unbolt from frame. 2-3 hours labor. Rebuilt units are readily available; rebuilding cores is 4-6 hours if doing in-house.

Estimated cost: $350-650

Symptoms: Fuel gauge reads empty or erratically regardless of actual level, Fuel smell around rear of vehicle, Visible external rust on tank straps and tank itself, Fuel leaking from seams or sending unit gasket

Fix: Original tanks rust from inside out due to ethanol and moisture. Sending units freeze in place due to corrosion. Tank removal requires dropping exhaust and supporting rear axle to lower enough for clearance—tight fit. 3-4 hours labor. New reproduction tanks available but quality varies; stainless aftermarket tanks are best option. Always replace straps, hoses, and sending unit gasket during tank work.

Estimated cost: $400-900

Typical onset: 90,000+ mi

Symptoms: Pinging/knocking under acceleration despite correct octane fuel, Poor fuel economy and lack of power, Difficulty starting when engine is hot, Vacuum advance canister doesn't hold vacuum when tested

Fix: Both mechanical and vacuum advance systems fail. Mechanical advance springs weaken or break; centrifugal weights seize from corrosion. Vacuum advance diaphragm ruptures. Testing requires advance timing light or vacuum pump. Rebuild kits available but distributor often needs complete overhaul: bushing replacement, new reluctor (electronic ignition), re-curve mechanical advance. 2 hours for basic vacuum can replacement; 4-5 hours for full rebuild.

Estimated cost: $150-450

Typical onset: 70,000-120,000 mi

Symptoms: Clunking from front end over bumps or when turning, Excessive negative camber causing inner tire wear, Wheel shimmy or vibration at highway speeds, Visible play when prying up on tire with car on ground

Fix: Upper ball joints on A-body are screw-in type, easier than most press-in designs. However, rust often freezes them in place requiring heat or control arm replacement. Load-bearing design means failure causes wheel to collapse inward—dangerous. Check during every alignment. Replacement requires unloading torsion bar and separating ball joint from spindle. 2 hours per side plus alignment.

Estimated cost: $300-550 per side