The TRW PSA328 is an 8-inch single-diaphragm brake booster (servo) fitted to several TVR models including the Cerbera, Griffith, Chimaera and S Series. It is a Ford-sourced unit, which makes replacement straightforward provided the right donor part is used. This page collates the equivalent part numbers and the Ford vehicles the same servo was fitted to, so a serviceable unit can be sourced from the Ford parts world when the TVR-branded item is unavailable.
| Detail | Value |
|---|
| Manufacturer | TRW |
| TRW part number | PSA328 |
| Type | Brake booster, 8 inch single diaphragm |
Use any of the following when searching for a replacement — they all refer to the same physical unit.
| Brand | Part number |
|---|
| TRW | PSA328 |
| Girling | 4110328 |
| Bosch | 0 986 485 090 |
| Ford | 1666345 |
| Ford | 89FB2005BC |
The servo on its own is only half the job. For the 4.2-litre Cerbera, the matching master cylinder is the one from the Fiesta Mk3 1.6 XR2i or 1.6i Ghia, which has a 22 mm bore. Bore size matters: fitting a master cylinder of a different bore will change pedal feel and braking effort, and can compromise safety. Verify the bore stamping on the donor unit before fitment.
The PSA328 was fitted across a wide spread of small Fords from the early 1980s into the mid-1990s. The Fiesta Mk3 hot variants are generally the most useful donors because they are the closest match in pedal feel and master-cylinder pairing.
| Variant | Capacity | Power | Years |
|---|
| 1.3 (FBD) | 1297 cc | 51 kW | 1983–1987 |
| 1.6 D (FBD) | 1608 cc | 40 kW | 1984–1989 |
| Variant | Capacity | Power | Years |
|---|
| 1.0 | 1119 cc | 33 kW | 1989–1995 |
| 1.1 | 1119 cc | 37 kW | 1989–1995 |
| 1.1 | 1119 cc | 40 kW | 1989–1995 |
| 1.3 | 1299 cc | 44 kW | 1989–1995 |
| 1.3 | 1297 cc | 44 kW | 1989–1992 |
| 1.3 CAT | 1299 cc | 44 kW | 1991–1997 |
| 1.4 | 1391 cc | 54 kW | 1989–1995 |
| 1.4 | 1391 cc | 52 kW | 1989–1995 |
| 1.4 CAT | 1391 cc | 54 kW | 1989–1995 |
| 1.6 | 1597 cc | 65 kW | 1989–1994 |
| 1.6 | 1597 cc | 66 kW | 1989–1992 |
| 1.6 i 16V | 1597 cc | 65 kW | 1994–1995 |
| 1.6 XR2i | 1597 cc | 81 kW | 1989–1994 |
| 1.6 Turbo (FBJT) | 1598 cc | 96 kW | 1990–1992 |
| 1.8 16V | 1796 cc | 77 kW | 1992–1995 |
| 1.8 D | 1753 cc | 44 kW | 1989–1995 |
| 1.8 XR2i 16V | 1796 cc | 96 kW | 1992–1995 |
| Variant | Capacity | Power | Years |
|---|
| 1.1 | 1087 cc | 37 kW | 1995–1996 |
| Variant | Capacity | Power | Years |
|---|
| 1.3 | 1299 cc | 44 kW | 1991–1996 |
| 1.8 D | 1753 cc | 44 kW | 1991–1996 |
| Variant | Capacity | Power | Years |
|---|
| 1.3 | 1297 cc | 40 kW | 1989–1995 |
| 1.6 D | 1608 cc | 40 kW | 1983–1989 |
| 1.8 D (FVJ) | 1753 cc | 43 kW | 1989–1995 |
- The Fiesta Mk3 1.6 XR2i and 1.6 Turbo (FBJT) are the pick of the donors for performance TVR applications — they were originally specified with the matching 22 mm-bore master cylinder.
- Reconditioned PSA328 units from specialist brake remanufacturers are often the easiest route, as good second-hand examples from 30-year-old hatchbacks are increasingly rare.
- Check the pushrod length and mounting stud pattern against the original TVR servo before committing — these can occasionally differ between variants of the same Ford part number.
Brakes are safety-critical. After fitting any replacement servo or master cylinder, bench-bleed the master cylinder, fully bleed the system, and test pedal feel and stopping performance at low speed before normal use. If in any doubt about bore size, fitment or condition, have the work inspected by a competent professional.
Compiled from a community-supplied cross-reference based on Yoyopart.com TRW PSA328 data — always verify part numbers and bore sizes against the physical components before relying on them.