Brake pads - inspection and renewal

Braking system / Brake pads - inspection and renewal

Warning: When working on brake components, take care not to disperse brake dust into the air or to inhale it, since it may contain asbestos which is injurious to health.

Warning: Always support the vehicle on axle stands before removing the roadwheel to service brake assemblies.

Front pads
Inspection
1 Refer to Chapter 1, Section 26.

Removal
2 To remove the pads, first jack up the front of the vehicle and support it on axle stands (see “Jacking and vehicle support”). Apply the handbrake and remove both front wheels.

3 Use an Allen key and unscrew the upper and lower caliper securing bolts (see illustration). Withdraw the caliper and tie it up out of the way. Do not allow the weight of the caliper to stretch or distort the brake hose (see illustration) .

2.3a Caliper securing bolt removal

2.3b Removing the caliper

4 Withdraw each pad by sliding it sideways from the wheel bearing housing. Note that the pads differ, the pad with the larger friction area being fitted to the outside.

5 The retaining spring can be detached from the wheel bearing housing whilst noting its orientation (see illustration). Renew the spring when renewing the pads.

2.5 Removing a pad retaining spring

6 Brush the dust and dirt from the caliper, piston, disc and pads whilst taking care not to inhale it. Scrape any scale or rust from the disc and pad backing plates.

7 If the pads are to be renewed, they must be replaced as a set on both sides at the front. If the original pads are to be re-used they must be refitted to their original positions each side.

Fitting
8 Using a piece of wood, push the piston back into the caliper. While doing this, check the level of the fluid in the reservoir and if necessary draw off some with a pipette or release some from the caliper bleed screw.

Tighten the screw immediately afterwards.

9 Relocate the retaining spring (see illustration).

2.9 Pad retaining spring is located as shown

10 Refit the inner pad (smaller friction area), followed by the outer pad. Locate the pad backing plate notches as shown (see illustration).

2.10 Refitting front brake pads

11 Refit the brake caliper, locating it at the top end first. Pivot the bottom end into position, align the upper and lower retaining bolt holes, then insert the bolts. Take care not to press the caliper in more than is necessary when fitting the bolts or the retainer springs may be distorted which, in turn, will give noisy braking.

Tighten the bolts to the specified torque.

12 On completion, the brake pedal should be depressed firmly several times with the vehicle stationary so that the brake pads take up their normal running positions. Check the fluid level in the reservoir and top-up if necessary.

Rear pads
Inspection
13 Refer to Chapter 1, Section 26.

Removal
14 To remove the pads, chock the front wheels, jack up the rear of the vehicle and support it on axle stands (see “Jacking and vehicle support”). Remove both rear wheels.

15 Release the handbrake then detach the handbrake cable from the caliper (see illustration).

2.15 Release handbrake cable (arrowed) from caliper

16 If the brake hydraulic hose connects to the underside of the caliper, undo the caliper upper retaining bolt (see illustration). If the hydraulic hose connects to the top of the caliper, undo both caliper retaining bolts. Note that these self-locking bolts must be renewed on reassembly.

2.16 Rear caliper bolt removal

Prevent guide pin from turning with openended spanner

17 If the upper retaining bolt was removed, pivot the caliper downwards (see illustration).

If both bolts were removed, carefully lift off and support the caliper.

2.17 Rear brake caliper removal

18 If the pads are to be re-used, mark them for identification to ensure that they are refitted to their original location. Their positions must not be changed (see illustration).

2.18 Removing rear brake pads

19 Brush all dust and dirt from the caliper, piston, disc and pads whilst taking care not to inhale it. Scrape any scale or rust from the disc and pad backing plates.

Fitting
20 Move the piston back into the caliper by turning it clockwise using either an Allen key or a pair of angled circlip pliers according to caliper type (see illustrations). As the piston moves back into the caliper, check the fluid level in the reservoir and if necessary draw some off with a pipette or release some from the caliper bleed screw. Tighten the screw immediately afterwards.

2.20a Retracting caliper piston using an Allen key

2.20b Retracting caliper piston using a pair of angled circlip pliers

21 Locate the respective brake pads in position.

22 Before refitting the caliper, piston position must be set to provide a 1.0 mm clearance between the outer pad and the caliper. Check the adjustment by temporarily refitting the caliper and retaining bolts (use the old ones) and check the clearance with a feeler blade as shown (see illustration). If adjustment is necessary, remove the caliper and rotate the piston clockwise or anti-clockwise until the correct clearance is achieved.

2.22 Checking outer brake pad-to-caliper clearance

23 Refit the caliper and insert the new self-locking bolts when adjustment is correct.

Tighten the bolts to the specified torque setting.

24 If new brake pads and/or discs have been fitted, it is necessary to carry out a basic rear brake adjustment before reconnecting the handbrake cable. To do this, apply a medium pressure to the brake pedal and depress it a total of 40 times (vehicle stationary).

25 Reconnect the handbrake cable to the caliper.

26 On completion, check handbrake adjustment.