Lotus Elise Service Notes page 328

D Lotus Service Notes Section JH
JH.6 - BRAKE DISCS
All four wheel brakes utilise a common brake disc which is sandwiched between each wheel and its hub,
being centralised by the hub spigot, and transmitting torque via the clamping force of the road wheel studs. No
separate disc fixings are used. The discs are made from an aluminium metal matrix, incorporating silicon
carbide, and must only be used in conjunction with the special brake pad material specified. A deposit from the
brake pads, which builds up on the swept area of the discs with use (and is evidenced by a dull grey band),
contributes to the friction characteristic and braking efficiency.
The condition of the brake disc friction surface is a major factor in brake performance and feel, with a
good surface quality and minimal run-out and thickness variation being required. After an extended lay up,
some surface corrosion may develop on the discs which will cause a degradation in braking quality until the
surfaces are cleaned up by normal brake action. Excessive run-out or thickness variation as a result of
overheating or extended wear, may cause brake judder and/or extended pedal travel due to pad 'knock off'.
Scoring and ridging of the braking surfaces will be exacerbated by operation in dusty or unmade road
environments, and will reduce braking performance.
No skimming or re-surfacing of the brake discs is permitted. If the disc becomes badly scored, or is out
of specification in any way, it should be renewed. NOTE: Ensure that there is no discernible free play in the
wheel bearings before attempting to measure brake disc run-out.
Brake disc thickness
New 26.0 mm (1.02 in)
Service minimum 24.9 mm (0.98 in)
Runout
New maximum 0.03 mm (0.001 in)
Front Disc Replacement
1. Remove the road wheel.
2. Remove the two bolts securing the brake caliper to the hub carrier, and withdraw the caliper from the disc.
Secure clear without straining the flexible hose.
3. Withdraw the disc from the hub.
4. Before re-fitting a disc, ensure that the mating face between disc and hub is scrupulously clean. Mount
the disc onto the hub and locate over the wheel studs.
5. Apply Permabond A131 (A912E7034) to the threads of the caliper fixing bolts. Fit the caliper over the
disc and secure to the hub carrier with the two bolts.
Note that the outermost of the alternative fixing holes in the hub carrier are used. Tighten to 45 Nm (33
Ibf.ft).
6. Refit the road wheel and operate the brakes before driving the car to set the brake pad position.
Rear Disc Replacement
Replacement of the rear discs is similar to that for the front discs, except that if the brake pads are
removed, it is not necessary to remove the brake caliper to enable the disc to be withdrawn from the hub.
Page 9 1998 / 03