The tank is made of transparent plastic, which allows you to visually control the liquid level.

The fluid level with the cap closed should not be higher than the "MAX" mark and not lower than the "MIN" mark.
Fill only with FMVSS 571, 116 DOT-4 and SAE J 1703 brake fluid.
When the disc brakes wear out, the fluid level will drop slightly. This is normal. If the fluid level is slightly above the "MIN" mark and the brake pads are almost at the wear limit, do not add fluid.
If, on the contrary, the level has dropped significantly in a short period of time, then this is a sign of fluid loss. In this case, you need to immediately find the leak. As a rule, these are worn cuffs in the wheel brake cylinders. It is recommended to check the brake system at a service station.
(Material copied from the portal: opelbook.ru)

Visitor comments