Volkswagen Air Cooled 1949-1969 Repair Guide

Master Cylinder

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REMOVAL & INSTALLATION





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Fig. Fig. 1 Cross-sectional view of a typical Volkswagen dual circuit brake master cylinder



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Fig. Fig. 2 Brake pedal pushrod clearance (S) should be 0.04 in.



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Fig. Fig. 3 To remove the master cylinder, detach the electrical wires from the warning lamp switch ...



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Fig. Fig. 4 ... then loosen the brake line fittings ...



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Fig. Fig. 5 ... and pull the lines away from the master cylinder



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Fig. Fig. 6 After removing the mounting bolts from inside the vehicle, pull the cylinder away from the firewall


CAUTION
Clean, high quality brake fluid is essential to the safe and proper operation of the brake system. You should always buy the highest quality brake fluid that is available. If the brake fluid becomes contaminated, drain and flush the system, then refill the master cylinder with new fluid. Never reuse any brake fluid. Any brake fluid that is removed from the system should be discarded.

The brake master cylinder on the 1980 Type 2 (Vanagon) is located under the dash. Remove the bottom and top dash covers for access.

  1. Drain the brake fluid from the master cylinder reservoir.
  2.  


WARNING
Do not get any brake fluid on the paint, as it will dissolve the paint.

  1. On Type 3 models, remove the master cylinder cover plate.
  2.  
  3. Pull the plastic elbows out of the rubber sealing rings on the top of the master cylinder, if equipped, or unfasten the fluid pipe seat nuts.
  4.  
  5. Remove the two bolts which secure the master cylinder to the frame and remove the cylinder. Note the spacers on Type 1 models between the frame and the master cylinder.
  6.  

To install:

  1. Bolt the master cylinder to the frame. Do not forget the spacers on Type 1 models.
  2.  
  3. Lubricate the elbows with brake fluid and insert them into the rubber seals.
  4.  
  5. If necessary, adjust the brake pedal free travel. On Type 1, 3, and 4 models, adjust the length of the master cylinder pushrod so that there is 5-7mm of brake pedal free-play before the pushrod contacts the master cylinder piston. On Type 2 models, the free-play is properly adjusted when the length of the pushrod, measured between the ball end and the center of the clevis pin hole, is 4.17 in.
  6.  
  7. Refill the master cylinder reservoir and bleed the brakes.
  8.  

OVERHAUL



  1. Remove the master cylinder from the car.
  2.  
  3. Remove the rubber sealing boot.
  4.  
  5. Remove the stop screw and sealing ring on the top of the unit.
  6.  
  7. Insert a small prytool in the master cylinder piston, exert inward pressure, and remove the snapring from its groove in the end of the unit. The internal parts are spring loaded and must be kept from flying out when the snapring is removed.
  8.  
  9. Carefully remove the internal parts of the unit and make note of their order and the orientation of the internal parts. If parts remain in the cylinder bore, they may be removed with a wire hook or very gentle application of low pressure air to the stop screw hole. Cover the end of the cylinder bore with a rag and stand away from the open end of the bore when using compressed air.
  10.  
  11. Use alcohol or brake fluid to clean the master cylinder and its parts.
  12.  
  13. It may be necessary to hone the cylinder bore, or clean it by lightly sanding it with emery cloth. Clean thoroughly after honing or sanding. Lubricate the bore with brake fluid before reassembly.
  14.  

To assemble:
  1. Holding the master cylinder with the open end downward, place the cup washer, primary cup, support washer, spring retainer, and spring onto the front brake circuit piston and insert the piston vertically into the master cylinder bore.
  2.  
  3. Assemble the rear brake circuit piston, cup washer, primary cup, support washer, spring retainer, stop sleeve, spring, and stroke limiting screw and insert the assembly into the master cylinder.
  4.  
  5. Install the stop washer and snapring.
  6.  
  7. Install the stop screw and seal, making sure the hole for the screw is not blocked by the piston. If the hole is blocked, it will be necessary to push the piston further in until the screw can be turned in.
  8.  
  9. Install the master cylinder and bleed the brakes.
  10.  

 
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