Why Rear Discs Made All the Difference
The Saab 900, particularly in turbocharged variants, came equipped with four-wheel disc brakes when many competitors still relied on rear drums. This choice reflected Saab’s commitment to active safety, providing superior stopping power and fade resistance that matched the car’s impressive performance capabilities.
The front brakes used ventilated discs with single-piston sliding calipers—a robust, reliable design that delivered excellent stopping power with minimal maintenance requirements. Saab sized these generously, with turbocharged models receiving larger diameter rotors to handle the additional performance. The vented design allowed heat to dissipate efficiently during spirited driving or mountain descents.
Rear disc brakes set the 900 apart from many contemporaries. While solid rather than ventilated, these rear discs provided more consistent braking performance than drums, particularly in wet conditions. The disc design eliminated brake fade during repeated stops and simplified maintenance compared to the adjustment-prone drum systems common in the 1980s.
The brake calipers themselves were manufactured by Girling (later Lucas), featuring a simple sliding design that proved remarkably durable. Unlike more complex multi-piston calipers, the single-piston sliding design was easy to service and rebuild. The guide pins required periodic lubrication with high-temperature grease—a simple maintenance task that prevented seized calipers and uneven pad wear.
Saab integrated a pressure-sensitive brake proportioning valve to balance front and rear braking forces. This mechanical valve adjusted hydraulic pressure to the rear wheels based on deceleration, preventing premature rear lockup while maintaining optimal braking balance. This system worked without electronic intervention, providing reliable, predictable braking characteristics across varying load conditions.
For modern 900 owners, maintaining the brake system is straightforward. Replacement parts remain readily available, and the conventional design allows any competent mechanic to service them. Upgrading to performance pads transforms the already-capable system into something truly impressive, proving Saab’s original engineering provided an excellent foundation.
