Grand AM L4-144 2.4L DOHC VIN T SFI (1997)
Brake Bleeding: Service and Repair
System Bleeding
General Information
PURPOSE
Bleeding operation is necessary to remove air from the hydraulic brake system whenever air is introduced into the brake system.
WHEN TO BLEED THE BRAKES
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It may be necessary to bleed the hydraulic system at all four brakes if air has been introduced through a low fluid level or by disconnecting brake
pipes at the master cylinder.
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If a brake pipe is disconnected at one wheel, only that wheel cylinder/caliper needs to be bled.
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If pipes are disconnected at any fitting located between master cylinder and brakes, then the brake system served by the disconnected pipe must be
bled.
PREPARING THE SYSEM FOR BLEEDING
On ABS equipped vehicles, it is necessary to perform the "Motor Re-home" procedure to ensure the brake fluid passages through the ABS Hydraulic
Modulator are open. See:
HELPFULL HINTS
The time required to bleed the hydraulic system can be reduced if the master cylinder reservoir is filled with brake fluid and as much air as possible is
expelled before the master cylinder is installed on the vehicle.
Manual Bleeding
RECOMMENDED TOOLS: J21472 Brake Bleeder Wrench or equivalent
Deplete the vacuum reserve by applying the brakes several times with the ignition "Off". Use extreme care to prevent brake fluid from contacting painted
surfaces.
CAUTION: Use only Delco Supreme II Brake Fluid (GM P/N 1052535) or an equivalent DOT-3 motor vehicle brake fluid.
1. Fill the master cylinder reservoir with brake fluid specified. Maintain the fluid level in the reservoir during the bleeding operation. It is necessary
to have an assistant in the vehicle to press on the brake pedal during the manual bleeding procedure.
2. If the master cylinder is known or suspected to have air in the bore, then it must be bled before any wheel cylinder or caliper in the following
manner:
a. Disconnect the front brake pipe connection(s) at the master cylinder.
b. Allow brake fluid to fill the master cylinder until it begins to flow from the front pipe connector port.
c. Connect the forward brake pipe(s) to the master cylinder and tighten.
d. Depress the brake pedal slowly one time and hold. Loosen the front brake pipe connection at the master cylinder to purge air from the bore.
Tighten the connection and then release the brake pedal slowly. Wait 15 seconds. Repeat the sequence, including the 15 second wait, until all
air is removed from the bore. Care must be taken to prevent brake fluid from contacting any painted surface. After all air has been removed at
the forward connection(s), bleed the master cylinder at the rear (cowl) connection(s) in the same manner as the front in step "d" above.
e. If it is known that the calipers and wheel cylinders do not contain any air, then it will not be necessary to bleed them.
3. Individual wheel cylinder or calipers are bled only after all air is removed from the master cylinder.
4. If it is necessary to bleed all of the wheel circuits, the following sequence should be followed:
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Right rear
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Left rear
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Right front
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Left front
5. Raise vehicle.
6. Place a proper size box end wrench (or special tool) over the caliper/cylinder bleeder valve.
