How to Adjust a Mustang Clutch Cable
- To reset the stock self-adjusting mechanism, see a standard shop repair manual.
- To adjust an aftermarket firewall adjuster, see below.
Preparing for Adjustment
Before adjusting the clutch cable tension, inspect everything in the system to ensure proper installation. This is especially important when combining parts from different sources.
It's critical to make sure the clutch cable housing stays at right angles to the surfaces at each end it's mounted to. This will minimize slack in the cable system and allow adequate clutch pedal travel.
- Securely attach the firewall adjuster to the firewall.
- Assemble the firewall adjuster correctly using the manufacturer's installation instructions. The adjuster mechanism has two parts: the half bolted to the firewall protrudes into the firewall, not out and away from it.
- Route the cable so the end of the outer housing seats squarely against the adjuster mechanism.
- The transmission end of the clutch cable housing must remain at a right angle to the bell housing. The stock retaining clip, located underneath the clutch fork cover, keeps the cable in the correct position.
Adjusting Clutch Cable Tension
The goal of adjusting the clutch cable is to put enough tension on it to keep the throwout bearing in light contact with the clutch diaphragm fingers, ensuring both proper clutch operation and long clutch life. Do not use the firewall adjuster to customize the pedal height or adjust where in the pedal travel the clutch engages or disengages. (Maximum Motorsports makes Clutch-Pedal Height Adjusters specifically designed to do that job correctly.)
- Grasp the cable outer housing with one hand.
- Pull it forward: toward the radiator and away from the firewall. This may take some effort. You need to remove all slack from the system, which forces the throwout bearing (by design) up against the pressure plate diaphragm.
- If there's no gap between the large, round, flat end of the housing and the front face of the adjuster, thread the adjuster into the firewall until you can see a small gap.
- While continuing to pull the outer cable housing away from the firewall, rotate the adjuster to thread it in or out of the firewall until the gap is about the thickness of a dime (0.050").
Confirming the Adjustment
- The cable should have just enough tension that the pedal moves down 1/2 in. when you press it with 5-8 lb of force. If the pedal moves more than that, increase the cable tension by screwing the firewall adjuster further out of the firewall. If it takes more than 8 lb of force to move the pedal 1/2 in., decrease the cable tension by screwing the adjuster further into the firewall.
- If the clutch won't disengage when you press the pedal to the floor, increase the cable tension by threading the adjuster out of the firewall.
- If the throwout bearing chirps when the clutch pedal is depressed and with the engine running, there isn't enough tension on the cable.
As the clutch disc wears, the friction material gets thinner, causing the cable tension to increase. This requires periodic "clutch adjustment," as it's commonly called, to compensate for clutch wear. However, what you actually want to do for regular maintenance is decrease the cable tension. You can do this by threading the adjuster into the firewall following the procedure in the "Adjusting Clutch Cable Tension" section above.
Ford equipped most Fox and all SN95 Mustangs with a self-adjusting mechanism designed to maintain proper clutch cable tension at all times. As the clutch disc wears, the mechanism automatically adjusts the cable tension so the clutch continues to operate correctly through its entire life.
A properly adjusted clutch cable has some tension on it. This keeps the throwout bearing in constant contact with the fingers on the clutch pressure plate diaphragm. That contact is essential for the self-adjusting mechanism to work. Contrary to popular belief, this is a design feature and does not prematurely wear out the Mustang throwout bearing.
The stock self-adjuster consists of a plastic quadrant/pawl gear assembly. The plastic wears out over time, but aftermarket pressure plates with higher clamp loads speed up that process. Even in a stock setup, age degrades the plastic and breakage becomes more likely with each passing year. The solution is to replace the plastic mechanism with long-lasting metal parts.
The typical replacement is a non-adjustable, aluminum quadrant. Be aware that once you remove the stock self-adjusting mechanism, clutch cable adjustment is no longer automatic! You must replace it with some method of adjusting cable tension. Maximum Motorsports does this with an assembly called a firewall adjuster, which lets you easily adjust cable tension from under the hood of your Mustang. To compensate for normal clutch disc wear, you'll need to adjust the cable tension periodically.
As the clutch friction disc wears and gets thinner, the end of the diaphragm fingers touching the throwout bearing push on the bearing, applying more and more load to the cable and increasing its tension. This starts to disengage the clutch, leading to clutch slippage. Keep up with adjusting your Mustang's clutch cable to maintain good performance and avoid premature clutch disc wear. Note that this adjustment process is not for changing the pedal position at the point of engagement/disengagement. Please see our Clutch-Pedal Height Adjuster that's designed to make that change correctly.)