BMW E30 Brakes Technical Articles
BMW e30 has hydraulic brakes, with either discs on all four wheels, or discs in front and drums on rear. Starting in 1986, Anti-lock Brake System (ABS) is available on e30 models. Brakes and pads should be regularly inspected for wear, although there is brake pad wear sensor on driver's front side and passenger rear side. It's good practice to replace brake fluid once a year.
BMW E30 stopping noisy brakes - easy DIY procedure