Renault Coupes/Sedans/Wagons 1975-1985 Repair Guide

Brake Master Cylinder



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Fig. Fig. 1 Brake master cylinder and reservoir-(C) is the maximum fill level

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Fig. Fig. 2 To check the brake fluid level, first unplug any electrical wires connected to the reservoir cap...

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Fig. Fig. 3 ... then unscrew the cap. Fluid should be 1 / 4 - 1 / 2 inch from top of opening

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Fig. Fig. 4 Add only clean and fresh DOT 3 brake fluid to achieve the proper level

When making additions of brake fluid, use only fresh, uncontaminated brake fluid which meets or exceeds DOT 3 standards.

Any sudden decrease in the level of fluid indicates a possible leak in the system and should be checked out immediately.

The master cylinder reservoir is located under the hood, on the left side firewall. Before removing the master cylinder reservoir cap, make sure the vehicle is resting on level ground and clean all dirt away from the top of the master cylinder. Pry off the retaining clip and remove the cap. The brake fluid level should be within 1 / 4 in. of the top of the reservoir.

If the level of the brake fluid is less than half the volume of the reservoir, it is advised that you check the brake system for leaks. Leaks in a hydraulic brake system most commonly occur at the wheel cylinder.

There is a rubber diaphragm in the top of the master cylinder cap. As the fluid level lowers in the reservoir due to normal brake shoe wear or leakage, the diaphragm takes up the space. This is to prevent the loss of brake fluid out the vented cap and contamination by dirt. After filling the master cylinder to the proper level with brake fluid, but before replacing the cap, fold the rubber diaphragm up into the cap, then replace the cap on the reservoir and tighten the retaining bolt or snap the retaining clip into place.

Be careful not to spill any brake fluid on painted surfaces, as it eats paint. Do not allow the brake fluid container or the master cylinder reservoir to remain open any longer than necessary; brake fluid absorbs moisture from the air, reducing its effectiveness and causing corrosion in the lines.