What is the correct sequence for bleeding wheel cylinders?

Left front, right front, left rear, right rear — bleeding one wheel cylinder at a time so the reservoir fluid level doesn't get dangerously low. This expels air from lines nearest the master cylinder first.

How far should the bleeder valve be opened when bleeding brakes?

Unscrew the bleeder valve ¾ of a turn, using Bleeder Wrench J 627, after attaching Brake Bleeder Tube J 628-A and placing its lower end in a clean glass jar.

How much brake fluid does it take to bleed each wheel cylinder?

Approximately ½ pint of fluid is required to bleed each wheel cylinder. Allowing the reservoir to empty will draw air into the hydraulic system.

What is the maximum pressure when bleeding brakes with a pressure tank?

Fluid should be applied to the master cylinder at a pressure not exceeding 35 pounds — too much pressure may blow out the expansion plug in the master cylinder. Pumping the pedal is not necessary with a pressure tank.

Can you reuse brake fluid caught in the jar during bleeding?

No. Discard the brake fluid deposited in the glass jar during bleeding; it is poor economy to attempt to clean fluid that has once been used.

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How to Bleed Drum Brakes - Wheel Cylinder Bleeding Sequence & Procedure (Manual)

Scanned service manual page on bleeding wheel cylinders with a figure

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Service manual page giving step-by-step instructions for bleeding brake wheel cylinders, including a labeled figure.

AI caption November 2005 · Photo 178 of 1134

This is page 9-13 of a vintage factory service manual's Brakes/Service section covering hydraulic brake bleeding procedures. Section (c) gives the correct sequence for bleeding wheel cylinders — left front, right front, left rear, right rear — bleeding one cylinder at a time to avoid draining the reservoir, and cautions against bleeding with any brake drum removed. Section (d) details manual bleeding without a pressure tank: attaching Brake Bleeder Tube J 628-A to the bleeder valve, opening the valve ¾ turn with Bleeder Wrench J 627, slowly stroking the brake pedal until fluid flows free of air bubbles, keeping the master cylinder filled (about ½ pint per wheel cylinder), and setting final fluid level ½" to 1" below the filler opening. Used fluid must be discarded. Section (e) covers pressure-tank bleeding, with five precautions to prevent air bubbles from entering the system (don't shake the tank, keep it at least ⅓ full of fluid, check line valves, etc.), and instructs applying no more than 35 pounds of pressure to avoid blowing out the master cylinder expansion plug. A photograph (Figure 9-6) shows the bleeder tube and wrench in use at a rear drum brake. Readers learn the complete step-by-step drum-brake bleeding process by both manual and pressure methods.

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Frequently asked questions

What is the correct sequence for bleeding wheel cylinders?: Left front, right front, left rear, right rear — bleeding one wheel cylinder at a time so the reservoir fluid level doesn't get dangerously low. This expels air from lines nearest the master cylinder first.
How far should the bleeder valve be opened when bleeding brakes?: Unscrew the bleeder valve ¾ of a turn, using Bleeder Wrench J 627, after attaching Brake Bleeder Tube J 628-A and placing its lower end in a clean glass jar.
How much brake fluid does it take to bleed each wheel cylinder?: Approximately ½ pint of fluid is required to bleed each wheel cylinder. Allowing the reservoir to empty will draw air into the hydraulic system.
What is the maximum pressure when bleeding brakes with a pressure tank?: Fluid should be applied to the master cylinder at a pressure not exceeding 35 pounds — too much pressure may blow out the expansion plug in the master cylinder. Pumping the pedal is not necessary with a pressure tank.
Can you reuse brake fluid caught in the jar during bleeding?: No. Discard the brake fluid deposited in the glass jar during bleeding; it is poor economy to attempt to clean fluid that has once been used.