All Volvos are equipped with a four wheel power-assisted disc brake system. Volvo was one of the first manufacturers to commit to the four wheel disc system on all of its cars. Disc brakes offer better stopping, ease of repair and simplified construction.
The calipers are manufactured either by Girling or ATE, so when ordering disc pads or caliper rebuilding kits, you must identify which you have. The name of the manufacturer is cast into the metal of the caliper. The brake discs are one piece castings. The discs on some models are vented for quicker heat dispersion.
Whenever adding to or replacing the brake fluid, it is imperative that the fluid be of SAE 70 R3 (SAE J 1703) quality or better. Fluid meeting DOT 3 or DOT 4 specifications is also acceptable. Using inferior brake fluids may result in premature failure of the hydraulic components or in impaired braking function. Fluids not meeting specifications may not withstand the great temperatures generated at the disc and caliper during braking. If the fluid boils within the lines, the pedal will feel spongy and give little response at the wheels.
Brake fluid is said to be hygroscopic, meaning that it attracts moisture. Water is the absolute last substance you want in the brake system, as it causes corrosion and can ruin seals. Any time it is necessary to add brake fluid, always use a fresh can. That half full can on the shelf has been through many heating and cooling cycles in the last six months; enough moisture has condensed out of the air within the can to pollute the fluid. You can use this old fluid for cleaning components during disassembly, but don't introduce any into the fluid system. Avoid mixing brake fluids from different manufacturers and never reuse old brake fluid.
In 1987, Volvo introduced its Anti-lock Braking System (ABS) on models in the 700 Series. This system prevents wheel lock-up (skidding) during hard braking, thus allowing the car to be steered during an emergency situation. (A wheel which is not turning will not provide steering response.) The ABS system uses a combination of mechanical, electronic and hydraulic components to sense impending lock-up at each wheel and meter the brake fluid flow to the wheels.
There are certain differences in repair procedures for ABS and non-ABS components. The ABS procedures, if different, are explained separately at the end of each repair section.