Rear Brake Pad Min Thickness

The replacement thickness of rear brake pads is 1mm, replace pads across the axle. Calipers have a square cut-out inspection window in the middle of their outer face.

Jack up car & remove wheel(s)

1. Ensure the handbrake is firmly applied, the car is level and in Gear/Park. Chock the front wheels very securely at the frontr. Jack up rear of car using a proper hydraulic jack at the rear subframe jacking-nub for this purpose. Then support the car on jack stands at the proper Jacking & Support Points.

2. With the car safely supported on jack stands, proceed to remove the wheel nuts (handbrake will hold the wheels still).

Removing pads from brake calipers

3. Locate the upper caliper guide bolt, the end is dust-cap'd by a small black plastic cylinder. The calipers hinge on the lower bolt when this upper bolt is removed by a 14mm socket or 7mm allen key.

4. The Calliper guide bolt is chromed and should be lubricated with a high temp grease (copper antiseize). If the chrome is heavily peeled and your brakes are wearing unevenly (rear calipers not pre 5-Jan-95) then replace the caliper guide bolts. If the caliper can't slide on the bolt effortlessly then braking will be on one rotor side only resulting in reduced braking performance.

5. Swing the caliper out of the way, you will see two wide V-springs (wire based) and guide plates (convoluted metal clip). They are designed to maintain pressure against the pads as kick-back springs.

6. Brake pads themselves snap into the Guide Plates, first remove the V-springs and the pads should unclip with light levering. From each pad remove the shim and note their orientation on the brake pad pegs. If your new brake pads do not have these shims (available from Dealers) you can re-use the old ones. Place a thin coating of copper antiseize between each of the shims and the brake pad, taking care not to get any on the rotor or brake pad surface.

7. Before fitting new brake pads the caliper piston will need to be screwed back into the caliper by an allen-bolt hidden under a hex-bolt at the rear of the caliper. The piston can not be forced back into the caliper by using C-Clamp like the front brakes.

8. Snap the brake pads into the clliper and replace the V-springs. Ensure the pads are seated fully and the shims haven't slipped (hence the antiseize grease). Swing the caliper/brake-pads back onto the rotor, ensuring the pads will pass the rotor edge. Then refit and tighten the caliper guide bolt to the correct torque, 34-39Nm, 25-29lb/ft.

9. On completing the pad change, verify the master cylinder is at the appropriate "Full" mark with fresh brake fluid.

Caliper guide bolt torque: 34-39Nm, 25-29lb/ft (different to front).

Re-Adjusting Rear Caliper

10. The rear caliper brake pads must be adjusted once fitted to bring them into contact with the rear brake disc. This is achieved by the same allen socket screw in the back of the caliper used to move the piston back into the caliper during pad replacement. Rotate this bolt until the pads just contact therotor and then back off 1/3 of a turn. After this adjustment the rear handbrake & rear pads are self-adjusting. Pre 5-Jan-1995 calipers are self-destructing with regard to this mechanism requiring replacement.

Bleeding brakes

11. Brakes should be bled to eliminate any air or moisture which has got into the system - ideally this should be repeated annually. See the Brake Bleeding & Brake Fluid Change section for the procedure.

Finishing off

12. Refit caliper guide bolt cover and wheel, putting a small amount of copper antiseize grease on the hub-wheel interface. Retorque wheel lug-nuts in a 1-3-5-2-4 pattern first to 50lb/ft then 80lb/ft to ensure even load and reduce chance of rotor warpage.

Wheel torque: 80lb/ft.

Last Upload: 18th March, 2002. V1.50a
URL: http://homepage.ntlworld.com/dorothy.bradbury/probemx/m_p5.htm