Ford implemented usage of a Hydraulically actuated Clutch in 2005+ Mustangs, no adjustment with a Hydraulic Clutch, the Slave Cylinder/Throwout Bearing assembly mounted within the Bellhousing. The 2004 & earlier Cable actuated Clutches could be adjusted.
You have either a Systemic component failure, Improper aftermarket Clutch assembly install, causing your issue. Generally, a worn out Clutch will present as the Clutch Pedal being further out before Clutch engages/Disengages.
If you have an aftermarket Clutch, and it was all installed correctly, there’s (2) methods to change Pedal height.
First, you need verify it isn’t a Systemic issue, or improper Slave Cylinder install, ruling out:.
A) Master Cylinder failure.
B) Slave Cylinder failure.
C) Clutch Hydraulic line “Ballooning” under load, System Hydraulic Fluid leak
D) If either A or B, you may have air in the System, affecting engagement height on Pedal.
E) Excessive play in the Pedal assembly, worn out Bushings, loose Fasteners, or a mechanical issue with the Pedal connection to the Master Cylinder.
F) Loose Bellhousing to Engine bolts
G) Adding an incorrect Fluid type to the Clutch Master Cylinder, more specifically- Synthetic.
Common issues. Further input will help, the following...
-Did you just purchase the Pony with this issue, or has it been yours & Pedal height to engagement just began to change over time?
-If purchased, did the previous owner claim it had a fresh Clutch, or did you install/have one installed ?
- If yes, Was it OEM or aftermarket?
-Is the fluid level low in the Clutch Master Cylinder?
- Ever difficult to get in Gear, from 1st to 2nd, or any slippage while moving?
Perform the following:
1) Eliminate any possible air in the System by bleeding the assembly through the master cylinder via a Vacuum type bleeder.(MityVac).
2) Check the Hydraulic line, from the Master Cylinder to where it enters the Bellhousing for Oil, and have somebody hold the Clutch in while you examine the Rubber line for “Balooning”. Engine off, Parking Brake enabled.
3) Is there any puddle under the Car, or is the lower Bellhousing, or area around Master Cylinder oily?
4) Top off the Clutch Master Cylinder Fluid. Cycle the Clutch Pedal from fully extended, to the Floor, 15-20 Times, repeatedly- Engine Running, then depress the Clutch, put in 1st Gear, let the Pedal out to move.
Any change, even if very slight, in Pedal height/Clutch engagement?
Good luck! John