This ATE brake master cylinder reservoir cap (PN 390425) seals the brake fluid reservoir to keep moisture and debris out on the Porsche applications listed below. ATE, a division of Continental AG, has been engineering hydraulic brake systems in Germany for over a century. An OEM supplier to manufacturers like Porsche AG, Mercedes-Benz, and Volvo, ATE produces factory-level rotors, pads, and hydraulic components built to strict European standards. Known for consistent pedal feel, proper fitment, and long service life, ATE remains a trusted choice for reliable, OE-quality braking performance.
Technical Details
- Manufacturer part number: 390425
- OE reference: 477 611 361 (477611361)
- Function: Seals the brake fluid reservoir to reduce contamination and help prevent leaks at the cap
- Quantity required: 1 per car
- Best practice: Replace the cap if the seal is hardened or if the reservoir has been opened for long-term storage
Fitment & Compatibility
Use the fitment table below to confirm year and model (356/914/924/928). Always verify reservoir style and level-sensor configuration where applicable.
If you’re sorting out reservoir parts, grommets, or master cylinder plumbing, send us your VIN and a quick description of what’s on the car now. We’ve been doing Porsche brake work for over 20 years, and we can help you avoid ordering the wrong reservoir hardware.
| Year | Make | Model | Submodel | Notes |
|---|---|---|---|---|
| 1956 | Porsche | 356A | ||
| 1957 | Porsche | 356A | ||
| 1958 | Porsche | 356A | ||
| 1959 | Porsche | 356A | ||
| 1960 | Porsche | 356B | ||
| 1961 | Porsche | 356B | ||
| 1962 | Porsche | 356B | ||
| 1963 | Porsche | 356B | ||
| 1964 | Porsche | 356C | ||
| 1965 | Porsche | 356C | ||
| 1964 | Porsche | 356SC | ||
| 1965 | Porsche | 356SC | ||
| 1970 | Porsche | 914 | ||
| 1971 | Porsche | 914 | ||
| 1972 | Porsche | 914 | ||
| 1973 | Porsche | 914 | ||
| 1974 | Porsche | 914 | ||
| 1975 | Porsche | 914 | ||
| 1976 | Porsche | 914 | ||
| 1977 | Porsche | 924 | ||
| 1978 | Porsche | 924 | ||
| 1979 | Porsche | 924 | ||
| 1980 | Porsche | 924 | ||
| 1981 | Porsche | 924 | ||
| 1982 | Porsche | 924 | ||
| 1978 | Porsche | 928 | ||
| 1979 | Porsche | 928 | ||
| 1980 | Porsche | 928 | ||
| 1981 | Porsche | 928 | ||
| 1982 | Porsche | 928 | ||
| 1983 | Porsche | 928 | ||
| 1984 | Porsche | 928 | ||
| 1985 | Porsche | 928 | ||
| 1986 | Porsche | 928 | ||
| 1987 | Porsche | 928 |