1972 GMC C1500

Typical onset: 80,000-150,000 mi or 50+ years of age-related wear

Symptoms: Rattling noise from front of engine on cold start that may disappear when warm, Rough idle and loss of power, especially under load, Check timing and find it's retarded several degrees despite setting distributor correctly, In severe cases: bent pushrods, skipped timing causing valve-to-piston contact

Fix: Replace timing chain, gears, and usually the nylon cam gear which deteriorates. Requires front accessory removal, harmonic balancer puller, timing cover R&R. While in there, replace oil pump and front seal. Budget 6-8 hours labor for experienced tech, more for first-timers. Parts run $150-300 depending on kit quality.

Estimated cost: $800-1,400

Symptoms: Hard starting when cold or after sitting; needs excessive cranking and pumping, Stumbling and hesitation on acceleration, Flooding or fuel leaks from carburetor base or accelerator pump, High idle or inability to adjust idle mixture screws effectively

Fix: Rochester 2GC or Quadrajet carbs dry out after years of sitting or ethanol fuel exposure. Full rebuild with kit including all gaskets, needle/seat, accelerator pump, and float adjustment. Count on 3-4 hours for proper teardown, cleaning, rebuild, and tuning. Some shops quote flat-rate 2.5 hours.

Estimated cost: $350-650

Symptoms: Soft or spongy brake pedal that goes to floor, especially on second pump, Brake fluid leaking from rear of master cylinder or at wheel cylinders, Uneven braking or pull to one side, Parking brake cables seized or ineffective

Fix: Single-reservoir master cylinders (pre-1973 dual) leak internally and externally. Wheel cylinders seize or leak after decades. Typical fix: new master cylinder, all four wheel cylinders, shoes, hardware, turn drums, flush/bleed lines. Figure 5-6 hours labor for complete four-wheel service including frozen hardware removal.

Estimated cost: $600-1,100

Symptoms: Fuel gauge reads empty, full, or erratically regardless of actual level, Rust flakes or sediment clogging fuel filter repeatedly, Fuel starvation under acceleration or at 1/4 tank despite fresh fuel pump, Visible external rust or pinholes on tank frame rails

Fix: In-cab fuel tanks rust from inside out, especially if stored with old fuel. Requires tank drop (1.5-2 hours), sending unit replacement or tank replacement/restoration. Many owners upgrade to external electric pump at this point. Tank coating kits available but labor-intensive. New reproduction tanks run $250-400.

Estimated cost: $450-900

Typical onset: 100,000+ mi or age-related

Symptoms: Excessive play at steering wheel (more than 2 inches free play before wheels respond), Wandering on highway requiring constant correction, Clunking when hitting bumps or changing direction, Grease leaking from steering box sector shaft seal

Fix: Saginaw recirculating ball steering boxes wear and can be adjusted first (30 minutes), but eventually need rebuild or replacement. Idler arm and Pitman arm also wear at pivots. Complete steering refresh: remanufactured box, Pitman arm, idler arm, alignment. Count 4-5 hours labor.

Estimated cost: $700-1,200

Symptoms: Visible rust perforation on frame rails, especially behind cab and rear spring hangers, Cab mounts deteriorated allowing cab movement or body-to-frame contact noises, Floor pan rust-through in footwells and rockers, Sagging or twisting frame under load

Fix: Not a simple fix—requires structural welding, patch panels, or frame section replacement. Cab mounts can be replaced DIY with hydraulic jack (all six mounts), 4-6 hours. Frame repair depends on severity: minor patching 8-12 hours, major sectioning 20-40 hours. Rust-free southern trucks avoid this.

Estimated cost: $800-5,000+

Typical onset: 120,000+ mi

Symptoms: Transmission fluid leaking from tailhousing seal or front pump seal, Slipping on 1-2 or 2-3 shift, especially when warm, Delayed engagement into Drive or Reverse (more than 2 seconds), No kickdown or mushy shifts due to vacuum modulator failure

Fix: GM TH350/TH400 automatics are durable but wear after 100k+ miles and leak from aged seals. External seal replacement (pan gasket, tailhousing, speedo gear) runs 2-3 hours. Full rebuild when clutches wear: 8-12 hours, $500-900 in hard parts. Vacuum modulator replacement (1 hour) often fixes shift quality.

Estimated cost: $250-2,200