1968 MERCURY MONTCLAIR

Typical onset: 60,000-100,000 mi or 40+ years regardless of miles

Symptoms: Rattling from front of engine on cold start that quiets after warmup, Rough idle, backfiring through carburetor, Loss of power, hard starting when hot, Check timing—if it jumps around or won't stay set, chain is stretched

Fix: Front-engine teardown: remove radiator, harmonic balancer, timing cover. Replace chain, both gears, and tensioner. Often find worn cam gear teeth. Budget 6-8 hours labor for experienced tech, more if water pump or oil pan gasket replacement is bundled. Always replace the oil pump drive gear while you're in there—they crack.

Estimated cost: $800-1,400

Typical onset: 80,000-120,000 mi or after years of short-trip driving

Symptoms: No forward engagement in Drive, Reverse works fine, Slipping on acceleration from a stop, Delayed engagement—long pause before clunk into gear, Burnt ATF smell, dark red or brown fluid

Fix: Pull transmission for rebuild or replace. Forward clutch pack burns out from low fluid, overheating, or worn seals. Full rebuild runs 12-16 hours; R&R plus rebuild of forward drum alone is 10-12 hours if you catch it early. Torque converter should be inspected or replaced. C6 cores are cheap, but machining and parts add up.

Estimated cost: $1,800-3,200

Symptoms: Gas smell in garage, fuel dripping from carb vents after sitting, Hard starting when hot, floods easily, Black smoke on startup, spark plugs fouling, Engine runs rich, poor fuel economy even for a big-block

Fix: Holley or Autolite carbs common—float needles wear, floats sink from old fuel. Rebuild kit plus ultrasonic cleaning: 2-3 hours if carb comes off clean. Check float level with gauge, replace needle/seat, verify power valve diaphragm. Ethanol fuel accelerates this. If carb body is corroded internally, replacement is smarter than rebuild.

Estimated cost: $250-600

Typical onset: Original rubber fails by age—50+ years

Symptoms: Wandering on highway, requires constant steering correction, Clunking over bumps from front end, Uneven tire wear on inside edges, Alignment won't hold, caster/camber specs drift

Fix: Upper control arm bushings harden and crack. Pressing old bushings out and new ones in takes 4-6 hours for the pair if arms stay on car; easier to remove arms. Alignment mandatory after. Lower ball joints usually need replacement at same time—add 2 hours and $150-250 parts. These big Mercs eat front-end parts when loose.

Estimated cost: $600-1,100

Typical onset: Any mileage—age and sitting causes seal hardening

Symptoms: Gear oil dripping from pinion area onto driveshaft, Oil spots under rear of car after sitting, Low gear oil level on dipstick (if equipped) or visible in housing

Fix: Drop driveshaft, replace pinion seal. Simple job if pinion nut hasn't rusted solid—1.5-2 hours. Critical to mark pinion position and use inch-pound torque wrench on reassembly or you'll change pinion depth and backlash. If bearing preload is lost, full rear-end setup required (add 4-6 hours). Check axle seals and wheel bearings while underneath.

Estimated cost: $180-400

Symptoms: Brake pedal slowly sinks to floor with steady pressure, Brakes work initially but fade after a few applications, No visible external leaks but reservoir level drops slowly, Soft pedal that pumps up temporarily

Fix: Single-reservoir master cylinder—internal seals fail with age. Replacement is 1-2 hours, but system must be bled thoroughly (another hour). Non-power and power brake versions differ. If booster diaphragm is also bad (common), add 2 hours and $200-350. Always inspect all four wheel cylinders and lines during this job—they're 50+ years old.

Estimated cost: $300-700

Symptoms: Fuel gauge erratic, stuck on empty or full, Rust particles clogging fuel filter repeatedly, Fuel smell from tank area, visible rust perforation, Engine stumbles or dies—pump pickup screen clogged with debris

Fix: Tank must come out—2-3 hours R&R. If savable, send for boil-out and sealer ($150-250 external service). Replacement tanks run $250-500 for reproduction. Sending unit fails from corrosion—$80-150 part. Always replace fuel pickup sock, line from tank to pump, and filter. Expect to find tank straps rusted; factor new hardware.

Estimated cost: $500-1,200