How to Troubleshoot a Toyota Truck Clutchby Don Bowman
A Toyota Truck clutch consists of the clutch reservoir, the master cylinder, hydraulic line, slave cylinder, throwout bearing release arm, throwout bearing, pressure plate and the clutch. When the clutch pedal is depressed, a rod on the pedal pushes on the clutch master cylinder creating hydraulic pressure in the line to the slave cylinder on the side of the transmission. In response to the hydraulic pressure, the rod in the slave cylinder is forced outward pushing on the control arm. This arm moves forward and contacts the pressure plate. The arms, which are arranged in a circle around the center of the pressure plate, are forced inward or down. This releases pressure on the clutch.
Start the vehicle and push in on the clutch just until the clutch is disengaged. If the clutch pedal disengages half way to the floor or more it is fine. If the pedal must be raised off of the floor most of the way up before it engages or can be disengaged by pushing the pedal just a short distance, then the clutch is severely worn and needs replacement. This is true only after making sure that the clutch slave circuit is working and not leaking fluid.
Understand that the circular clutch is sandwiched between the pressure plate and the flywheel. The pressure plate is bolted to the flywheel with the clutch underneath it. It has a set of strong springs in a circular pattern on the top of the plate. Every time the arms are pushed in they counteract the force of the springs and allow the pressure plate to lift taking the pressure off of the clutch. The clutch is the direct connection between the engine and the transmission. The clutch has splines in the center and the transmission input shaft is slid into it. Every time the clutch is forced to spin, so is the transmission. The more that the clutch wears, the higher the arms extend.
Check the clutch reservoir and make sure that it is full of brake fluid. Make sure that there are no leaks around the reservoir or the master cylinder. If so, they must be replaced.
Check the condition and operation of the slave cylinder. Have a helper push in and out on the clutch while the slave is observed for leaks and movement. If the reservoir is low on fluid and the slave cylinder is leaking at the rod, replace it and bleed it at the slave. This is a common problem with a Toyota where the slave cylinder creates a leak. If the slave was fine, then the clutch needs replacement.