Do not pump the brakes. Just hold the brake pedal down firmly and let antilock work. A slight brake pedal pulsation might be felt or some noise noticed, but this is normal.
Chevrolet Cobalt Service & Repair Manual. Valve Cover, Replace
Removal
1.
Loosen vent hose clamp at air cleaner
resonator, air cleaner intake duct clamp at air cleaner outlet resonator.
2.
Loosen air cleaner outlet resonator
to throttle body clamp, located forward of accelerator cable bracket ...