Front
FRONT BRAKE DISC, REPLACEMENT (ALL VERSIONS)General
Note: It is essential that the following instructions be followed to ensure satisfactory operation.
When replacing a front brake disc, the position in which the disc is installed on the hub must be determined by measurement if the hub is not marked. The purpose is to minimize the lateral runout of the disc (max. 0.06 mm = 0.0024 inch) when the component is mounted in position. Gauge ring 9995419 must be used instead of the wheel when measuring the lateral runout. The ring should be mounted on the hub and the nuts tightened to 85 Nm (63 ft. lbs.). If runout is excessive, a variation in thickness may develop as the disc becomes worn, leading to brake vibrations.
Note: Marked 'hub units' were introduced on production models as from week 11, 1990 and as spare parts as from week 17, 1990. (See left-hand illustration below.) The type of marking may differ; the component may be identified either by a paint spot or by a physical marking.
Since the disc position is not marked on spare hubs for 1987 and earlier models, this must be carried out as part of the replacement procedure. The marking may then be used when replacing the disc subsequently.
All brake disc markings are scribed on the component as shown in the right-hand illustration below. Care must be taken, when mounting the disc on the hub, to ensure that the scribed mark is as close as possible to the hub marking as permitted by the wheel studs.
This type of 'matching' minimizes brake disc runout.
The procedure for replacing front brake discs on cars with separate (spare) hubs (models to 1987 inclusive).
The procedure for replacing front hub units (models from 1988 on).
Front brake disc, installation/replacement
Applicable to cars with replacement 2-piece brake disc/hub (models to 1987 incl.)
Special tools: 999 2715, 5418
Note: There were cars prior to model year 1986 that were equipped with separate hubs (i.e. models with the earlier type of integral brake disc and hub that were a one piece hub and rotor). If rotors are needed to be replaced on this type car, they must be replaced with the two piece type rotor and hub assemblies, as these rotor assemblies are no longer available from Volvo OEM. The replacement units are two piece and will interchange with the earlier one piece hub and rotor unit previously used.
L1. Jack up and support car. Remove wheel
L2. Remove brake pads
Remove lower bolt and raise piston housing.
L3. Remove
^ brake caliper. Use 10 mm Allen key. Place caliper on support arm, taking care to avoid damage to brake hoses.
^ guide pin
^ brake disc
L4. Check that hub flange is clean. Remove grit, oxidation, etc. with scraper blade and steel brush
If hub is marked as described in L9, proceed to operations L11-L16.
If hub is not marked, carry out operations L5-L16.
L5. Remove grease cup and split pin
Tighten castellated hub nut to 10 Nm (7.5 ft. lbs.).
Purpose is to eliminate bearing play which may yield incorrect values when lateral runout of hub is measured (see below).
L6. Mount gauge ring 999 5419
Ensure that mating surfaces of hub and gauge ring are absolutely clean.
Mount gauge ring 999 5419 (from tool kit 999 5418) on hub. Tighten nuts diagonally to 85 Nm (63 ft. lbs.).
Note: Readjust bearing tightness as per operation L10 when runout has been measured.
L7. Set up measuring equipment as illustrated
Place dial gauge probe on gauge ring measuring surface.
L8. Turn hub slowly and locate maximum runout point
Maximum lateral hub runout: 0.030 mm (0.00118 inch).
Replace hub if runout exceeds above value.
L9. Mark hub 180° from maximum runout point
Mark with small punch mark as illustrated.
Note: Remove dial gauge from contact with gauge ring to prevent damage by vibration when punching hub.
Remove measuring equipment.
L10. Slacken hub nut half a turn
Tighten nut to 1.5 Nm (1.1 ft. lbs.) i.e. finger-tighten. Install new split pin. If pin hole is not opposite opening in nut, tighten nut further until pin fits in next hole.
Install grease cup using socket 999 2715.
L11. Cars with ABS only:
Remove dirt from sensor and sensor wheel with soft brush.
L12. Install brake disc
Ensure that mating surfaces on hub and disc are clean.
Install disc with marking as close to hub marking as permitted by wheel studs.
Insert locating pin and tighten to 8 Nm (6 ft. lbs.).
For confirming accepted disc runout check according to regular procedures.
L13. Install brake caliper
Use new bolts. Tighten to 100 Nm (74 ft. lbs.).
L14. Press back caliper pistons
Press back pistons slowly and carefully using universal pliers, taking care to avoid damage to dust seals. Ensure that seals are slightly inside piston ends to prevent damage from pad backing plates when caliper is lowered into position.
L15. Install brake pads
Lubricate pad backing plates with thin coating (0.1 - 0.2 mm) of silicone grease, P/N 11 61 325-4.
Note: This applies only to Bendix (DBA) calipers. Pad backing plates on Girling calipers are provided with rubberized anti-squeal coating. Lower caliper into position.
Install guide sleeve/pin retaining bolt. Use new bolt.
Tighten to 34 Nm (25 ft. lbs.).
Note: Take care when lowering caliper to avoid puncturing guide pin gaiter, otherwise sliding action may be impaired by entry of water.
Note: Correct torque is extremely important. If torque is too low, joint may work loose.
If torque is too high, guide sleeve may be deformed.
Operate brake pedal several times and check fluid level.
L16. Refit wheels as per markings
Finger-tighten nuts, then torque diagonally to 85 Nm (63 ft. lbs.).
Test drive car.
Recommend customer to limit hard braking whenever possible during first 500 miles after repair in order to allow the brakes to bed in properly.
Front Brake Disc, Replacement
Cars from 1988 on
Special tool: 999 5418
M1. Jack up and support car. Remove wheel
M2. Remove brake pads Remove lower bolt and raise piston housing.
M3. Remove:
^ brake caliper. Use 10 mm Allen key. Place caliper on support arm, ensuring that brake hose is not damaged.
^ guide pin
^ brake disc
M4. Check that hub flange is clean. Remove grit, oxidation, etc. with scraper blade and steel brush
If hub is marked, proceed to operations M - M14.
If hub is not marked as described, proceed to operation M5.
M5. Mount gauge ring 999 5419
Ensure that mating surfaces of hub and gauge ring are absolutely clean.
Mount gauge ring 999 5419 (from tool kit 999 5418) on hub. Tighten nuts diagonally to 85 Nm (63 ft. lbs.).
M6. Set up measuring equipment as illustrated
Place dial gauge probe on gauge ring measuring surface.
M7. Turn hub slowly and identify maximum runout point
Maximum lateral hub runout: 0.030 mm (0.00118 inch). Replace hub if runout exceeds above value.
M8. If unmarked, mark hub 180° from maximum runout point
Mark with small punch mark as illustrated.
Note: Remove dial gauge from contact with gauge ring to prevent damage by vibration when punching hub.
Remove measuring equipment.
M9. Cars with ABS only:
Remove dirt from sensor and sensor wheel with soft brush.
M10. Install brake disc
Ensure that mating surfaces on hub and disc are clean.
Install disc with marking as close to hub marking as permitted by wheel studs.
Note: Hub markings may differ. Insert locating stud and tighten to 8 Nm (6 ft. lbs.).
M11. Install brake caliper
Use new bolts. Tighten to 100 Nm (74 ft. lbs.).
M12. Press back caliper pistons
Press back pistons slowly and carefully using universal pliers, taking care to avoid damage to dust seals. Ensure that seals are slightly inside piston ends to prevent damage from pad backing plates when caliper is lowered into position.
M13. Install brake pad
Lubricate pad backing plates with thin coating (0.1 - 0.2 mm) of silicone grease, P/N 11 61 325-4.
Note: This applies only to Bendix (DBA) calipers. Pad backing plates on Girling calipers are provided with rubberized anti-squeal coating. Lower caliper into position.
Install guide sleeve/pin retaining bolt. Use new bolt.
Tighten to 34 Nm (25 ft. lbs.) on two-piston caliper and 27 Nm (20 ft. lbs.) on single-piston type.
Note: Take care when lowering caliper to avoid puncturing guide pin gaiter, otherwise sliding action may be impaired by entry of water.
Note: Correct torque is extremely important. If torque is too low, joint may work loose.
If torque is too high, guide sleeve may be deformed.
Operate brake pedal several times and check fluid level.
M14. Refit wheels as per markings
Finger-tighten nuts, then torque diagonally to 85 Nm (63 ft. lbs.).