Augmenting Your Challenger’s Clutch System

The slave cylinder is located at the transmission. When you press your foot on the clutch pedal, fluid inside the clutch master cylinder is pressurized and sent down through the clutch lines to the clutch slave cylinder. 

The fluid inside the slave cylinder pushes against a piston, also inside the slave cylinder. That piston operates the movement of the throwout bearing, disengaging the clutch. When you release the pedal, the system works in the opposite direction, engaging the clutch.

Signs of failure of your slave cylinder would include fluid leakage, and failure of the clutch to disengage. To check for fluid leakage, the first step is to jack up the car.

Then, look on the ground for fluid. If there’s no fluid on the ground, next check the underside of the car, especially in the area of the transmission bell housing. This is where fluid will collect if there is a clutch hydraulic leak.

Testing the clutch disengagement is a bit simpler. With the car off, depress the clutch and place the transmission in gear. Then start the vehicle’s engine with the clutch pedal held to the floor. If the car moves, the slave cylinder is most likely bad.

You will have to also check the fluid level in the master cylinder, and the condition of the master cylinder. If the fluid level is adequate and there are no leaks at the master cylinder, the slave cylinder is your culprit.

Also, you should replace your slave cylinder with an aftermarket unit if you are doing “hard” driving on the street. If you’re running the car at high speed or high RPM, doing burnouts, etc., on the street, you probably would benefit from a stronger aftermarket unit. If you do track days or race, a beefier unit would definitely help your performance.

The throwout bearing resides on your Challenger’s transmission input shaft. When the clutch pedal is depressed, the slave cylinder pushes on the throwout bearing. As the bearing moves forward on the input shaft towards the pressure plate, the face of the bearing presses against the fingers of the pressure plate. This overcomes the spring pressure inside the pressure plate and disengages the clutch. Engagement is achieved by the reversal of this process.

Aftermarket throwout bearings are constructed of superior materials that are designed to last longer and be more durable than stock units. They also are adjustable, which makes use with dual disk clutch assemblies easier, and allows for adjustment of the pedal height to your personal preference. 

How about throwout bearing failure? Throwout bearing failure can usually be identified by noise. If you are driving along, and hear a rumbling noise in your driveline, it could be the throwout bearing. If the noise is present while the clutch pedal is depressed, and goes away when the clutch is released, it’s time to replace your throwout bearing.

Another type of failure can be breakage. If the clutch pedal goes right to the floor when attempting to depress it, the plastic surrounding the bearing has most likely broken, and the bearing has dislodged from its proper place. Unfortunately, if you believe this is the case, the transmission must be removed from the vehicle for a visual inspection.

Clutch lines carry the hydraulic fluid from the master cylinder to the slave cylinder. When the Challenger’s clutch pedal is actuated, the fluid is pressurized and sent through the lines down to the slave cylinder, actuating the throwout bearing.

Factory clutch lines are typically just rubber hoses. During long periods of driving, heat from the engine compartment can cause rubber lines to swell. That can result in a spongy or vague feel in the clutch pedal. Stainless lines are typically constructed with a Teflon inner core and stainless-steel webbing on the outside. This makes the lines much more resistant to swell under high heat situations.
Rubber lines can also swell under high pressure.

When the clutch is applied repeatedly under high-performance driving, the rubber lines can swell. The construction of stainless lines prevents pressure swell. Also, the ability of the stainless steel lines to resist swelling under pressure and heat provides a better clutch pedal feel under all circumstances.

Signs of clutch line failure are deterioration/cracking of the rubber and fluid leakage. Visually inspect the lines for any signs of rubber deterioration. Be sure to check any bends in the lines for cracking. Check the inside and outside surfaces of all bends. This is the area most prone to cracking. Check the entire hose for any signs of leakage or damage.

Pay special attention to the ends of the lines for leakage. These points are sealed with either a metal or rubber o-ring. If the sealing points are leaking, there’s a good chance the hose itself is not far behind. Change the hose and seals at the same time.

The pilot bearing is a small bearing that slides into the center hole in the rear end of the crankshaft. The front end of the transmission input shaft slides inside the pilot bearing.

The bearing supports the end of the input shaft. It also allows the engine and flywheel to continue rotating at speed when the clutch is actuated and the input shaft begins to slow down.

The pilot bearing should be replaced every time you change the clutch. It should also be replaced if it is making noise. Start as mentioned before, by placing the vehicle in neutral and starting the engine. 

Then depress the clutch and place the vehicle in gear. If you have a noise, you’ve now narrowed it down to either the throwout bearing or the pilot bearing.

Next, place the transmission in neutral, and release the clutch pedal. If the noise is still there after the pedal is released, but goes away when the pedal is depressed, the pilot bearing is the issue.

To change the pilot bearing, you must first jack up and properly support the vehicle. Remove the negative battery terminal.

Next, remove the driveshaft. Remove the starter motor. Unbolt the flywheel bolts. Disconnect the clutch fluid lines.

Remove the bolts holding the engine and the transmission together. Remove the transmission. Unbolt the pressure plate bolts and remove the clutch assembly.

Now you’re left with the pilot bearing in the center of the flywheel, slid into the crankshaft. Use a pilot bearing puller to remove the pilot bearing from the end of the crankshaft. Thoroughly clean the cavity in the end of the crankshaft.

Start the pilot bushing evenly into the cavity. Use a socket the same outer diameter of the bearing, and a hammer, to gently tap the bearing into place.

Be sure to make sure it goes in straight. Then, reverse the remainder of the procedure to install the remaining components. Be sure to bleed the Challenger’s clutch hydraulic system according to recommendations before attempting to drive the vehicle.