Genuine Audi Clutch Master Cylinder

Audi 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.
• Master Cylinder
  8E1-721-401-AJ
  Q: How to remove and install the components related to the Clutch Master Cylinder on Audi A4?

  A:

  In order to take the parts off, one must first of all detach the connection of the cable to the negative terminal of the battery. Then, undo the cowl cover and electronic box containing PCM and auxiliary relay center in order to expose hydraulic lines. To prevent the possibility of spilling brake fluid, put rags under the clutch pedal to soak up any spills, so that brake fluid does not get into the plenum chamber and touch the transmission; in this case, clean the area completely. In the cowl chamber, remove the fluid supply hose between the clutch master cylinder and jam the line. Disconnect the pressure line plug of the clutch master cylinder and pull off the clip and plug out the line to avoid fluid leakage and contamination. Take away the brake master cylinder reservoir retaining bolt and electrical connector to the fluid level sensor to be able to tilt the reservoir on its axis to reach the upper brake master cylinder/booster mounting bolt. Unattach the two long bolts that hold the brake master cylinder/booster to the pedal assembly bracket. Removal of the left side under-dash panel, removal of the clutch pedal and over center spring take place inside the vehicle. Unscrew the brake pedal off of the booster, take the pinch bolt that attaches the steering column shaft universal to the steering gear input shaft off, and detach the universal joint of the steering gear input shaft. Dislodge the electrical connector to the switch of clutch pedal, brake light switch, and accelerator pedal module. Unscrew the upper mounting fastener of the pedal assembly and drop the pedal assembly. Clamp is released by pushing down on the sides of the holding clip without letting the clutch pedal be free and trying to break the clutch pedal switch. Disengage the pin holding the clutch master cylinder to the clutch pedal, push the pushrod pin out and take off the clutch pedal. Unscrew the mounting bolts, unscrew the master cylinder of the pedal assembly, be careful not to pour fluid on the carpet. To install, undo all the steps of removal, verify that all the fasteners are tightened to the appropriate torque amounts, bleed the clutch hydraulic system and verify that the brake fluid is at the right level in the reservoir by adding fluid to the reservoir as needed.