A guy brought in a 73 COUGAR 351CJ with inoperable clutch. Looked under the dash and the support bracket had failed. It has non-serviceable press-in bushings. Had a machinist replace the bearings with roller bearings and replace all linkage bushings -
On Ill -
4001508 - Main Supt
7551- Pedal Bushings
7517 - Bushings on Equalizer
7523 - Retracting Spring - Notice it also has an adjustment.
You need to go though the entire system. Remove driver's seat ...
Your '55 SHOP MANUAL will describe the '57