How to Bleed a Clutch Master Cylinder for a 4-Cylinder on a 2001 Chevy S-10

by Kyle McBride

    Chevrolet's 2001 S-10 models equipped with the 2.2-liter, four-cylinder engine and a five-speed manual transmission have a hydraulic clutch actuation system. The system operates by converting clutch pedal effort into hydraulic pressure by means of the clutch master cylinder and then delivering that pressure to the slave cylinder in the transmission through a hydraulic line. Air bubbles trapped within the hydraulic system cause a spongy feel to the clutch pedal, clutch drag and undue wear to the clutch components. Bleed the air from the system to restore normal clutch operation.

    Items you will need

    • Floor jack
    • Jack stands
    • Shop rags
    • Catch pan
    • Six-point, box-end wrench set
    • Hydraulic clutch fluid, GM part number 12345347 or equivalent DOT 3 brake fluid
    Step 1

    Locate the clutch master cylinder on the driver's side firewall inside the engine compartment. Wipe the master cylinder cap to remove dirt or debris. Remove the cap and fill the reservoir to the “Full” line with approved fluid.

    Step 2

    Lift the front of the S10 with a floor jack and place jack stands under the truck's frame rails. Lower your S10 onto the jack stands.

    Step 3

    Find the slave cylinder bleeder valve on the driver's side of the bell housing, just above the clutch hydraulic line connector. Position a catch pan in place under the bleeder valve.

    Step 4

    Have a helper depress and hold the clutch pedal in the full-down position. Open the bleeder valve slightly, using a six-point, box-end wrench, to allow pressure to bleed from the system. Open it only enough to allow fluid to escape, as the system is under pressure and opening the valve too far will allow a forceful stream to jet from the orifice. Tighten the bleeder valve once the leakage subsides. Have the helper release the clutch pedal.

    Step 5

    Repeat Step 3 until there are no air bubbles in the discharge stream. Check the fluid level in the master cylinder reservoir after every few bleeding cycles and add as needed to ensure that the reservoir never runs dry. If it runs dry and sucks in air, you'll have to start over.

    Step 6

    Add fluid to the reservoir up to the “Full” line. Install the reservoir cap.

    Step 7

    Pump the clutch pedal several times, then test the clutch operation with the engine running. Repeat the bleeding process again if clutch performance is still unsatisfactory.

    Step 8

    If clutch performance is still unsatisfactory after repeating the bleeding process, remove the clutch master cylinder reservoir cap. Rapidly depress and release the clutch pedal for about 30 seconds to expel any remaining air bubbles in the master cylinder. Top off the fluid level in the reservoir and install the cap.

    Warnings

    • After repairs, test drive the S-10 in a controlled area such a parking lot before taking the truck into traffic.
    • Do not confuse the clutch master cylinder with the brake master cylinder. The clutch master cylinder is smaller, with only one line attached to it. The brake master cylinder is larger with two lines attached to it.
    • Do not release the clutch pedal during the bleeding procedure while the bleeder valve is open or you will introduce air into the system.
    • Do not recycle bled fluid back into the reservoir. Bled fluid can contain water and other contaminants.
    • Always discard used fluid according to local regulations.
    • Do not shake or agitate the fluid prior to adding it to the reservoir. Aerated fluid can hold bubbles up to 24 hours and will make the clutch spongy if it is used. Allow the fluid to rest for 24 hours if the fluid is holding air bubbles in suspension.
    • Use only approved GM hydraulic clutch fluid or DOT 3 brake fluid.
    • Exercise caution when using DOT 3 brake fluid. It can damage painted and plastic parts.

    References

    • GM Service and Parts Operation Manual, 2001 Chevrolet/Geo S10 Pickup; General Motors Corporation