How to Troubleshoot a Ford Manual Clutchby Don Bowman
A Ford manual clutch uses a cable or series of rods to actuate the clutch throughout bearing. It does not use a hydraulic slave cylinder. These were replaced with the hydraulic style activation to allow for less pressure of the pedal. Manual clutches, however, are easier to maintain and allow for much greater adjustments or different dimensions of the clutch. On a hydraulic clutch, simply turning the flywheel can be more than the slave cylinder can adjust for and causes a no-disengagement of the clutch.
Start the engine. Most clutch problems can be diagnosed sitting in the car. The clutch consists of a pressure plate, a clutch or friction disc, a flywheel, a throw out bearing and the clutch linkage. The clutch is sandwiched in between the flywheel and the pressure plate. The pressure plate uses spring pressure to hold the clutch against the flywheel hard enough that it will not slip. In the center of the pressure plate, there are a series of arms in a circle angling upwards. When the clutch pedal is depressed, it pushes a throw out bearing against these arms, forcing them down toward the front of the car. When these arms are forced down, they allow the pressure plate to move in the opposite direction and release tension on the clutch, releasing it. The thicker the clutch or the better the condition of the clutch, the more the pedal must be depressed to release the clutch; conversely, the worse the clutch, the less the pedal must be pressed to release it.
Press the pedal all the way to the floor. Lift the pedal slowly and notice where the pedal is before the clutch begins to grab; from a couple inches off the floor to just over the halfway point, the clutch is still good. If the pedal must be close to all the way out before engagement, then there is not much material left on the clutch and it needs to be replaced as soon as possible. The problem with letting a clutch go too long when it's bad is that the rivets holding the clutch material on will begin to contact the flywheel and create grooves in it. This requires replacing the flywheel as well as the clutch, effectively doubling the cost.
Inspect the adjustment on the linkage before condemning the clutch. Look for the arm coming out of the transmission bellhousing on the left driver's side. The linkage can be seen running alongside the transmission used to push on this arm. This is called the throw out bearing release arm. The throw out bearing is attached with two spring clips to this arm. It is on a pivot so that if the arm is pushed toward the rear, the throw out bearing is pushed forward. When the release arm is pushed, the throw out bearing is pushed forward and presses on the pressure plate arms. As the arms are moved in toward the flywheel, the pressure plate releases the clutch. Grab the release arm and move it back and forth. There should be very little play in the arm; however there must be some because you do not want the throw out bearing to touch the pressure plate when released. This would soon wear out the bearing and the arms on the pressure plate if they were continuously in contact. There should be just enough play that you can feel where it is not contacting the pressure plate. If there is too much or not enough, use a wrench and adjust the adjustment rod to get the right play.
Check the amount of clutch left to see if the car can be driven for a short time (if the clutch is going bad). To do this, put the car in third gear, rev the engine slightly and let the clutch out rapidly. If the car wants to stall immediately, the clutch should go another 1,000 miles. If there is any noise when the clutch is operating normally, then the rivets are grinding at the flywheel.
Check the flywheel for warping. If, when the clutch is engaged, you feel pulsations in the pedal or the car jerks, it needs a new flywheel.
Check the condition of the throw out bearing. If a grinding noise is heard every time the clutch is put in and goes away when released, the throw out bearing is bad and will soon wear out the pressure plate arms, making it impossible to shift or get out of gear. This must be replaced as soon as possible.