Bleeding your Z31 brake system the right way

Any time you remove a part of you brake system (Master cylinder, Caliper) or the system develops a leak, or if the fluid in the master cylinder runs low, Air will enter the system. To remove this air the system must be bleed. If the Master cylinder was removed or fluid in the master cylinder runs low a complete bleeding of the system will be needed. If just a caliper or line was removed then just that brake will need to be bled.

Things Needed

Large Container of dot3 brake fluid
A length of 3/16” Rubber Tubing
Empty Clear container ( Glass or plastic)
8mm line wrench
1 Good Assistant

Order of wheels to bleed

Left Rear
Right Rear
Right Front
Left Front

image description — Bleed brakes in the following order: C, D, A, B
(image from: Nissan Motor Company Factory Service Manual)

Procedure to Bleed Brake System

First, apply the brake pedal several times with the engine off to remove the vacuum built up in the booster. The pedal should feel firm after a few presses.

Ensure the master cylinder is full of fluid and keep it at least half full throughout the process.

⚠️ Note: If the fluid drops too low at any point, air may enter the system. You must restart the process if this happens.

⚠️ Caution: Never mix fluid types or reuse old fluid — this can damage brake system components.

Step-by-Step Bleeding Order

Begin with the Left Rear wheel, the farthest from the master cylinder. Then proceed in this order:

Left Rear
Right Rear
Left Front
Right Front

Bleeding Procedure

Loosen the bleeder valve to break it free, then re-tighten slightly so it can be easily opened and closed.
Place one end of a clear plastic hose on the bleeder valve and submerge the other end into a small container filled with fresh brake fluid.
Example: Bleeder valve setup with tubing and fluid container.
Have an assistant pump the brakes several times to build pressure. On the final pump, they should hold the pedal down firmly.
With the pedal held, open the bleeder valve slightly. Allow fluid and air bubbles to exit through the tube.
When the fluid flow slows or the pedal reaches the floor, close the valve. Repeat until no air bubbles are seen in the fluid.
Tighten the bleeder valve to 6.5 ft-lbs. Move on to the next wheel and repeat the procedure.

✅ Check the master cylinder often to ensure the fluid level doesn’t drop.

Hope this helps with Bleeding your braking system of air.

Sources Used

1984-1989 Nissan Factory Service Manual