Volvo Coupes/Sedans/Wagons 1970-1989 Repair Guide

Brake Disc (Rotor)

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See Figure 1



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Fig. Fig. 1: Periodically inspect the brake system to ensure adequate pad and rotor thickness-these are considered normal wear items

REMOVAL & INSTALLATION



Except 700 Series

See Figures 2 through 10

  1. Loosen the lug nuts a few turns. Elevate the car and safely support on jackstands.
  2.  
  3. Remove the wheel.
  4.  



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Fig. Fig. 2: Raise and properly support the vehicle before working under it



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Fig. Fig. 3: If equipped with retaining pins, drive them out with a hammer and drift



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Fig. Fig. 4: With pliers, grasp and pull out the pad from its mounting position-it may be necessary to pry the pad to gain clearance from the disc



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Fig. Fig. 5: Use a piece of stiff wire and hang the caliper out of the way

  1. Remove the brake pads and remove the brake caliper. Do not disconnect the brake hose running to the caliper; use a piece of stiff wire and hang the caliper out of the way.
  2.  



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Fig. Fig. 6: Remove the disc retaining screws-if resistance is high, stop and apply a penetrating lubricant to loosen them for a few minutes

  1. Loosen and remove the small retaining screws on the face of the disc. They will be difficult to loosen; don't strip the heads.
  2.  



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Fig. Fig. 7: If needed, apply penetrating lubricant to the mounted disc to ease removal

  1. Remove the brake disc. It may be necessary to tap on the disc with a rubber or rawhide mallet to loosen it from its place. Don't use a metal hammer; you can crack the disc.
  2.  



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Fig. Fig. 8: Remove the disc-if necessary, use a soft faced hammer to lightly tap it free

  1. When reassembling, make sure the disc sits squarely on the mount and install the retaining screws.
  2.  



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Fig. Fig. 9: Separate the backing plate from the pad-do not forget to reinstall it later



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Fig. Fig. 10: To provide clearance for the new (thicker) pads, press the pistons into the caliper. This causes brake fluid to flow back to the master cylinder

  1. Install the brake caliper and pads. Check that the disc can turn freely and that the caliper is properly seated. Since the brake line was not disconnected, it should not be necessary to bleed the brakes.
  2.  

  1. Reinstall the wheel and lower the car to the ground. Final tighten the lug nuts to 80-90 ft. lbs. (108-122 Nm).
  2.  

700 Series

See Figure 11

  1. Loosen the lug nuts a few turns. Elevate the car and safely support on jackstands.
  2.  
  3. Remove the wheel.
  4.  
  5. Remove the brake pads and remove the brake caliper. Do not disconnect the brake hose running to the caliper; use a piece of stiff wire and hang the caliper out of the way.
  6.  
  7. Use a 10mm Allen wrench to disconnect the caliper bracket.
  8.  
  9. Remove the center grease cap, the cotter pin and the castle nut.
  10.  
  11. Remove the outer wheel bearing and place in a clean, protected location.
  12.  
  13. Remove the brake disc and the inner wheel bearing. It may be necessary to use a bearing puller (Volvo 2722 or similar) if the inner bearing is difficult to remove. Place the bearing in a clean, protected location. Remove the inner bearing seal if it remains in the hub.
  14.  

Cars with ABS have the pulse wheel mounted within the disc. This toothed wheel must be removed and transferred to a new rotor if one is being installed. Use a universal gear puller and carefully lift off the pulse wheel. Use a bearing installation tool and a press to install the pulse wheel on the new disc.

  1. When reassembling, the wheel bearings must be cleaned and repacked. The reader is referred to the Front Wheel Bearings-700 Series portion of Suspension & Steering .
  2.  
  3. Install the inner bearing in the hub. Using a seal installation tool, install a new grease seal. Make sure the face of the seal is even with the hub.
  4.  
  5. Install the brake disc, the outer bearing and the castle nut. Rotate the disc while tightening the nut to 41 ft. lbs. (55 Nm). Loosen the nut 1 / 2 turn.
  6.  



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Fig. Fig. 11: Always use a new cotter pin when installing the disc-bend the ends as shown

  1. Tighten (finger tight) the nut to 13 inch lbs. (1.5 Nm) and install a new cotter pin. If the cotter pin will not go through the nut into the hole, tighten the nut slightly.
  2.  
  3. Install the brake caliper. Use new attaching bolts and tighten them to 72 ft. lbs. (97 Nm).
  4.  
  5. Install the brake pads.
  6.  
  7. Install the wheel and lower the vehicle to the ground. Final tighten the wheel lugs to 60 ft. lbs. (81 Nm).
  8.  

INSPECTION



See Figure 12

The brake disc may be inspected without removal, however viewing the back (inner) face of the disc is difficult. Ideally, the caliper should be removed allowing full access to both faces of the disc. Run-out measurements must be taken with the disc mounted on the car and the wheel bearings properly adjusted.



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Fig. Fig. 12: Use a micrometer to measure the brake disc thickness

The friction surface on both sides of the disc should be examined for surface deviations such as scoring or corrosion. Minor radial scratches and small rust spots may be removed by resurfacing or fine polishing the disc. The lateral run-out of the disc must not exceed 0.004 in. (0.1mm) for the front, and 0.060 in. (0.15mm) for the rear, measured at the outer edge of the disc. Do not mistake a faulty wheel bearing adjustment, or an improperly mounted disc for lateral run-out.

Actual disc thickness, which varies from model to model (see specifications), should not vary more than 0.0012 in. (0.03mm) when taken at several points on the same disc. If the disc is worn at any point to less than the minimum permissible thickness (see specifications), it must be replaced. A brake disc which is too thin cannot handle the heat generated by braking. If the disc cracks under braking, the wheel can lock instantly, causing loss of control and a possible collision.

After the disc has been resurfaced, measure the thickness to insure it is still above the minimum specification. A resurfaced disc should be washed in solvent inside and out to remove any metal filings which could get caught in the wheel bearings. Dry the disc thoroughly and repack the wheel bearings and inner hub. A new set of brake pads is highly recommended when installing a new or reconditioned disc.

 
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