Summary
The Audi 4000 has 4 recalls spanning the 1980-1986 production run, with the most serious being a brake caliper hose fitting defect on 1981 models where porous material in the caliper's threaded bore allows brake fluid to seep out under hard braking, gradually depleting the reservoir and potentially causing complete brake failure.
The 1986 model year has a rear seat belt buckle issue where the buckle, made by AFG, can appear fully latched but remain unlocked, releasing the occupant during hard braking or a collision. On 1985 models with automatic transmissions, an idle stabilizer valve can wear and cause rough or fluctuating idle that worsens over time into noticeable driveability problems. The earliest production, covering 1980 models, has a rear trunk side member that may not have been fully welded, and in a rear-end collision the member can break free and puncture the fuel tank, causing fuel to leak.
