Peugeot 504 Restoration Guide
The 504 is mechanically robust but susceptible to corrosion in predictable locations. Know what to look for before you buy.
The Golden Rule
Prioritise structural rust over mechanical issues. Engines and running gear are durable and well-supported by parts — serious bodywork rot can make a car unrestorable or extremely expensive to fix.
Rust — Priority Locations
Inspect these areas first and most carefully on any prospective purchase:
Front Inner Wings / Strut Tops
Severity: High · Structural. Costly to repair properly. Open the bonnet and push down on each front corner — any give indicates a problem. Critical for MOT and safety.
Sills (Rocker Panels)
Severity: High · Structural. Often hidden by cladding or body filler. Get underneath with a torch. Poke with a blunt instrument to test for rust bubbling or collapse.
Floor Pan
Severity: High · Structural. Check from underneath — particularly under the front and rear seats. A rotten floor pan is expensive to repair correctly.
Rear Suspension Mounts
Severity: High · Safety-critical. Directly affects handling and safety. Inspect the inner wheel arch and the trailing arm mounting points.
Wheel Arches (All Four)
Severity: Medium-High. Check behind rubber trim where water collects. Look for blistering paint on the outside arch lip.
Door Bottoms
Severity: Medium. Common and often visible. Check all four doors in the bottom 5cm — the fold traps moisture.
Rear Valence / Lower Rear Panel
Severity: Medium. Cosmetic but often advanced. Can indicate that the floor has been wet as well.
Special Note: Two-Door Models
Italian-built Coupés and Cabriolets are especially susceptible to rot due to the Turin production environment. Inspect these more carefully than sedans. The Cabriolet's sills and floor are particularly at risk. Allow significantly more budget for bodywork restoration on a two-door.
Mechanical Issues
Shock Absorbers
Older cars will need these replaced — check for excessive bounce and handling vagueness. Renewal transforms the driving feel.
Wiring Harness
Age-related electrical fragility. Check all lighting and instrument functions. Dry, brittle insulation is a fire risk.
Exhaust Manifolds
Original manifolds crack with age. Budget for replacement — cracks cause noise and affect engine performance.
Brake System
Hoses, master cylinder, and calipers all age. Budget for a full overhaul: fresh fluid, new hoses, rebuilt calipers.
Suspension Bushings & Ball Joints
Renewal is straightforward and transforms the driving feel. Alignment should be checked after any suspension work.
Engine-Specific Notes
| Engine | Main Concerns |
|---|---|
| XD88 / XD90 Diesel | Extraordinarily durable if maintained. Check injector condition and injection timing. Look for weeping around injectors. |
| XN 2.0L Petrol | Reliable. Check for oil leaks at rocker cover and sump. Watch for head gasket condition on high-mileage examples. |
| PRV V6 | Requires more careful maintenance. Check K-Jetronic injection condition on late cars. Timing chain and tensioner wear. ZF automatic can be expensive to rebuild. |
Parts Suppliers
Parts availability is reasonable for a car of its age, with specialist suppliers in France and Germany covering most mechanical and body needs. Two-door trim is the hardest category.
Community Resources
Parts Availability at a Glance
Pro Tips
· The XD diesel family was used in agricultural, industrial, and marine applications — parts are findable from non-automotive sources.
· The PRV V6 is shared with Renault 25/30 and Volvo 264/265 — check Volvo and Renault specialists when Peugeot sources run dry.
· Argentine parts for Argentine-spec cars need Argentine sources — Sevel's supply chain was separate.