Clutch — description and check

1. All vehicles with a manual transaxle use a single dry-plate, diaphragm-spring type clutch. The clutch disc has a splined hub which allows it to slide along the splines of the transaxle input shaft. The clutch and pressure plate are held in contact by spring pressure exerted by the diaphragm in the pressure plate.

2. The clutch release system is operated by hydraulic pressure. The hydraulic release system consists of the clutch pedal, a master cylinder and fluid reservoir, the hydraulic line, a release (or slave) cylinder which actuates the clutch release lever and the clutch release (or throw out) bearing.

3. When pressure is applied to the clutch pedal to release the clutch, hydraulic pressure is exerted against the outer end of the clutch release lever. As the lever pivots the shaft fingers push against the release bearing. The bearing pushes against the fingers of the diaphragm spring of the pressure plate assembly, which in turn releases the clutch plate.

4. Terminology can be a problem when discussing the clutch components because common names are in some cases different from those used by the manufacturer. For example, the driven plate is also called the clutch plate or disc, the clutch release bearing is sometimes called a throughout bearing, the release cylinder is sometimes called the operating or slave cylinder.

5. Other than to replace components with obvious damage, some preliminary checks should be performed to diagnose clutch problems. These checks assume that the transaxle is in good working condition.

) The first check should be of the fluid level in the clutch master cylinder (see Tune-up and routine maintenance). If the fluid level is low, add fluid as necessary and inspect the hydraulic system for leaks. If the master cylinder reservoir has run dry, bleed the system as described in Clutch hydraulic system — bleeding and retest the clutch operation.
) To check clutch spin-down time, run the engine at normal idle speed with the transaxle in Neutral (clutch pedal up -engaged). Disengage the clutch (pedal down), wait several seconds and shift the transaxle into Reverse. No grinding noise should be heard. A grinding noises would most likely indicate a problem in the pressure plate or the clutch disc.
) To check for complete clutch release, run the engine (with the parking brake applied to prevent movement) and hold the clutch pedal approximately 1/2-inch from the floor. Shift the transaxle between 1st gear and Reverse several times. If the shift is rough, component failure is indicated. Check the release cylinder pushrod travel. With the clutch pedal depressed completely, the release cylinder pushrod should extend substan If it doesn’t, check the fluid level in the clutch master cylinder.
) Visually inspect the pivot bushing at the top of the clutch pedal to make sure there is no binding or excessive play.
) Crawl under the vehicle and make sure the clutch release lever is solidly mounted on the ball stud.