Genuine Audi 100 Clutch Master Cylinder

Audi 100 Clutch Master Cylinder Parts and Q&A

• Master Cylinder
  4A1-721-401
  Q: What are the steps and precautions for working with the clutch master cylinder and hydraulic fluid on Audi 100?

  A:

  Mark the caution on the dangers of working with hydraulic fluid. The clutch master cylinder is fitted inside the car at the bottom of the bracket on which the clutch and brake pedals are mounted and the hydraulic is fed by the brake master cylinder reservoir. The first step is to take out the trim panel and the heater floor outlet ducts under the steering column, and cover the floor under the pedals to prevent the leakage of hydraulic fluids. Uncouple the flexed hydraulic fluid hose between the fluid reservoir and the master cylinder as well as the supply hose between the fluid reservoir and the slave cylinder. Slowly remove the hydraulic fluid supply hose of the cylinder, and possibly insert a fitting bolt at the end of the same. Undo the hydraulic pipe union at the bottom of the cylinder and loosen the pipe. Take out the clip and the clevis pin connecting the lever on the clutch pedal to the master cylinder pushrod and unscrew the mounting bolts, and remove the master cylinder as an assembly within the car. Audi may not have repair kits but may be obtained through a motor factor. To remover the master cylinder, clean the outside parts, remove the rubber boot, and the pushrod. When necessary, loosen locknut, unscrew clevis and locknut then take pushrod out of rubber boot. Take out the circlip at the end of the mouth of the cylinder, and also remove the washer, piston, and spring, observing that the larger end of the spring is in touch with the piston. Wash the parts and inspect them regarding wear and rust; in case the piston and the bore is too worn or rusted, replace the entire cylinder. In case they are not worn, take off the seals on the piston and replace them. Wet the new seals in hydraulic fluid and place over the piston with the lips of the seal oriented towards the end of spring. Dip the piston in hydraulic fluid, then insert the spring in the cylinder taking care not to put it in too deep. Install the washer and find the circlip in the groove. Validly apply some grease to the end of the pushrod, position it on the piston, and put the rubber boot on it. Attach the clevis and locknut screwing the locknut. On left hand drive models, to change clevis position such that the gap between clevis hole center and master cylinder mounting face measures 109.5 mm +/- 0.5 mm. Remove and refit To refit the cleavage, change cleavage position so that the distance between the center of cleavage holes and the center of the mounting face of the master cylinder is 109.5 mm +/- 0.5 mm.