Renault Coupes/Sedans/Wagons 1975-1985 Repair Guide

Master Cylinder

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REMOVAL & INSTALLATION



Except LeCar
  1. Drain the fluid from the master cylinder with a syringe such as a turkey baster, or a sponge.
  2.  


WARNING
Brake fluid is a fabulous paint remover. Take great care to avoid its contact with the car's sheet metal.

  1. Disconnect the brake lines from the cylinder.
  2.  
  3. Unbolt the cylinder from the power booster.
  4.  
  5. Installation is the reverse of removal. Tighten the mounting nuts to 15 ft. lbs. Adjust the pedal travel. Bleed the system. Adjust the master cylinder operating clearance.
  6.  

LeCar


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Fig. Fig. 1 To remove the master cylinder, unplug any wires connected to the reservoir cap ...



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Fig. Fig. 2 ... and remove the cap ...



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Fig. Fig. 3 ... then remove as much brake fluid from the reservoir as possible



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Fig. Fig. 4 Using a flare nut wrench, start disconnecting the brake lines from the front ...



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Fig. Fig. 5 ... and work back to the last brake line



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Fig. Fig. 6 With the brake lines positioned out of the way, unplug the wire for the brake light switch



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Fig. Fig. 7 Remove the master cylinder retaining nuts ...



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Fig. Fig. 8 ... and remove the master cylinder from the vehicle

Renault states that the LeCar master cylinder is not rebuildable.

  1. Drain the fluid with a syringe such as a turkey baster, or with a sponge.
  2.  


WARNING
Brake fluid is a fabulous paint remover. Take great care to avoid its contact with the car's sheet metal.

  1. Disconnect the brake lines from the master cylinder.
  2.  
  3. Disconnect the wiring from the master cylinder.
  4.  
  5. Unhook the pushrod from the brake pedal and pull it out of the master cylinder.
  6.  
  7. Unbolt and remove the master cylinder.
  8.  
  9. Installation is the reverse of removal. Coat the mating surface of the cylinder with RTV sealant. Check, and if necessary, adjust the pedal travel. Bleed the brake system.
  10.  

OVERHAUL



Renault states that the LeCar master cylinder is not rebuildable. All the other models have rebuildable master cylinders. The primary and secondary pistons must be replaced as units and are not repairable.

R-12, R-15, R-17, Gordini, Alliance and Encore


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Fig. Fig. 9 Exploded view of the master cylinder used on all but the Fuego and R-18-secondary piston assembly (A), primary piston assembly (H) and snapring (B)

  1. Place the master cylinder in a soft-jawed vise.
  2.  
  3. Remove the reservoir by pulling it upward and wiggling it off.
  4.  
  5. Using a wood dowel, push in on the pistons about 5mm and remove the setscrew from the bottom of the cylinder.
  6.  
  7. Continue pushing in the piston and remove the snapring and stop washer. Remove the primary piston. The secondary piston will have to be removed with compressed air. A bicycle pump will do.
  8.  
  9. Check all parts. If the cylinder bore is excessively scored or pitted, the whole thing will have to be replaced. The bore can be repaired with a brake cylinder hone, available in most auto parts stores. The hone is drill-mounted. Follow the instructions that come with the hone. If no instructions accompany the hone, insert the hone, chucked into an electric hand drill, into the cylinder bore. Start the drill and push and pull the hone through the cylinder. NEVER let the hone stay in one place. Two to four passes should be enough. Clean all parts in clean brake fluid.
  10.  
  11. Coat all parts with clean brake fluid and reassemble.
  12.  

R-18, Fuego and Sport Wagon


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Fig. Fig. 10 Dimensions (in mm) for the R-18 and Fuego master cylinder tool



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Fig. Fig. 11 Install the homemade tool onto the master cylinder as shown



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Fig. Fig. 12 Removing the secondary roll pin

  1. Obtain a 1 / 4 inch diameter steel rod, about 385mm (15.16 inches) long. Shape it as shown in the accompanying illustration.
  2.  
  3. Using this tool, compress the pistons.
  4.  
  5. Place a 3.5mm (0.138 in.) drill bit in a vise. Position the master cylinder so that the drill bit penetrates the roll pin of the secondary piston.
  6.  
  7. Rotate the cylinder so that the drill bit screws itself into the roll pin, then pull out the pin. Do the same with the primary piston roll pin.
  8.  
  9. Remove the wire tool and take out the pistons.
  10.  
  11. For cleaning and honing, see Step 5 of the R-12 procedure, above.
  12.  
  13. Installation is the reverse of removal. Install new roll pins.
  14.  

OPERATING CLEARANCE ADJUSTMENT



Except LeCar


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Fig. Fig. 13 Adjusting the master cylinder operating clearance-note the pushrod protrusion (X), locknut (E), clevis (C) and link length (L-4.961 inches)

Operating clearance is determined by the length of the booster pushrod that protrudes past the face of the booster. Protrusion should be 9mm (0.354 in. or 23 / 64 in.). Adjustment is made at the pushrod clevis, at the brake pedal. Loosen the clevis locknut and turn the clevis until the proper protrusion is reached.

LeCar
  1. Loosen the master cylinder pushrod locknut.
  2.  
  3. Turn the pushrod until pedal free travel, at the pedal surface, is 13 / 64 in.
  4.  
  5. Tighten the locknut.
  6.  

 
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