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Lotus Evora. Manual - part 13

Lotus Service Notes

Section CK

Cambolt illustration

Castor Adjustment

Castor is the angle from vertical of the steering axis of the wheel when viewed from the side. Its primary

purpose is to provide a natural straight running tendency of the steered wheels with forward vehicle motion.

Castor angles have a complex interaction with other steering geometries and if unbalanced or outside of speci-

fication, can result in various stability and handling deficiencies.

The eccentric cams fitted at both front and rear inboard pivots of the lower wishbone (see 'Camber Ad-

justment above) are also used to adjust camber. By moving the rear pivot axis outwards, and the front pivot

inwards, the lower swivel joint is moved forwards to result in an increase in castor angle. To reduce the effect

of this adjustment on camber angle, the front pivot point will need to be moved laterally about three times the

distance, and in the opposite direction, to the rear pivot point movement.

After adjustment, ensure that the nuts are tightened to 86 Nm (only at ride height).

CK.3 - WISHBONE PIvOT BUSHES & SWIvEL JOINTS

Pivot Bushes

The upper and lower wishbone pivot bushes are bonded rubber type with a plastic flanged outer sleeve,

an alloy inner sleeve, and an aluminium interleaf sleeve within the rubber bush to control the flexing character-

istic. The rubber material specification has been selected to optimise the handling/refinement balance. The

flanged end of the bush incorporates a snubbing feature to limit the axial distortion of the bush, with each bush

arranged to resist braking forces transmitted through the suspension; Both top wishbone bushes are inserted

from the front, and both bottom wishbone bushes from the rear. A chamfer is provided in the wishbone bore

for this purpose.

The bushes may be pressed out of the wishbone eyes, and new bushes fitted using suitable press tool

dollies. Smear the outer surface of the new bush with IPC 'P-80' rubber lubricant emulsion (A082C6042v) to

ease fitment, and assemble in the direction detailed above.

FRONT

Top & bottom

steering swivels

Vertical Castor angle

c27

Lotus Service Notes

Section CK

Steering Swivel Joints

The steering swivel joint housed in the outboard end of both the top and bottom wishbones, uses a steel

ball pin located in a synthetic spherical bearing cup pressed into the wishbone and retained by a swaging op-

eration. The joint requires no maintenance other than a visual inspection of the dust gaiter, and is replaceable

only as an integral part of the wishbone assembly.

Damper Pivots

The lower eye of the damper is fitted with a zero compliance, through bolted, spherical joint which may

be replaced using suitable press tools. The upper eye houses a bonded rubber bush, with a steel outer sleeve

and an alloy inner sleeve. The bush may be replaced using suitable press tools.

CK.4 - ANTI-ROLL BAR

The tubular steel anti-roll bar is mounted beneath the front subframe in rubber bushes retained by extruded

alloy clamps. One clamp secures the bar at each side to a bolt fixed, alloy extrusion, bridging the chassis drop

towers for the lower wishbone front and rear pivots. Each end of the bar loops upwards through the lower

wishbone and uses a short ball jointed drop link and forged steel bracket to connect to the rear leg of the lower

wishbone. At each side, a washer crimped to the bar, bears against the inboard end of the chassis mounting

bush to provide lateral location of the bar.

The drop link ball joints require no maintenance, and are replaceable only as part of the drop link as-

sembly. The chassis mounted bushes are lubricated with rubber grease on assembly, but require no routine

maintenance.

ARB illustration

To be revised

Lotus Service Notes

Section CK

CK.5 - SUSPENSION DISASSEMBLY/ASSEMBLY

The suspension may be disassembled without the use of any special tools other than spring compressor

clamps if the spring and damper are to be separated. With the car on a wheel free lift and with the front wheels

removed:

1. Remove the wheelarch liner(s) as appropriate.

Hub Unit

2. Remove the two bolts securing the brake calliper to the hub carrier, release the flexible hose from the top

wishbone, and support the calliper aside without straining the brake hose. Release the single countersunk

screw, and remove the brake disc.

3. Release the harness connector from the wheel speed sensor, release the harness from any suspension

components, and secure the harness aside. Release the single screw securing the wheel speed sensor,

and withdraw the sensor from the hub carrier.

4. Release the four hex. head securing bolts and withdraw the hub unit from the hub carrier. Note that this

unit is common to all four wheels.

Hub Carrier

5. Remove the nut securing the track rod ball joint into the steering arm, and use a ball joint splitter to sepa-

rate the joint from the arm.

6. Remove the nut securing the top swivel joint to the hub carrier, and use a ball joint splitter to separate the

joint.

7. Remove the nut securing the lower swivel joint to the hub carrier, and use a ball joint splitter to separate

the ball pin from the carrier. Lift the carrier and hub unit from the car.

Damper and Spring

8. If the damper and spring are to be separated, it is recommended to remove the complete assembly of

spring/damper/top mounting bracket from the car in order that spring compression may be carried out in

the safest manner.

Remove the 4 bolts securing the top mounting bracket to the subframe, and the single bolt securing the

lower end of the damper to the bottom wishbone bracket. Withdraw the assembly to a workbench.

9. Using spring compressor clamps and taking all suitable safety precautions, unload the spring seats and

remove the bolt securing the top end of the damper to the mounting bracket.

10. Separate the spring, damper and top bracket, noting the spring top seat cushion, and unload the spring

clamps.

Upper Wishbone

11. Release the 'P' clip securing the brake hose to the wishbone, and the front and rear pivot bolts, and with-

draw the wishbone from the subframe. The captive nuts for the pivot bolts are retained in channels in the

chassis extrusions, replacement of the nutplate for the rear pivot requiring removal of the crash structure

joining plate.

Note that the steering swivel ball joint is retained in the wishbone by a swaging operation, and is serviced

only as part of the upper wishbone assembly. For pivot bush replacement, see CK.3.

Lower Wishbone

12. To aid re-assembly, match mark the eccentric cam adjuster positions at both pivot points for the lower

wishbone. Release the anti-roll bar drop link from the wishbone, noting that a 5mm hexagonal socket is

provided in the end of the ball pin stud to aid this process. Remove both pivot bolts and eccentric cam

adjusters, and withdraw the wishbone.

Note that the steering swivel ball joint is retained in the wishbone by a swaging operation, and is serviced

only as part of the lower wishbone assembly. For pivot bush replacement, see CK.3.

Lotus Service Notes

Section CK

13. If necessary, release the four bolts and remove the damper lower fixing bracket from the lower wishbone,

and the remaining bolt securing the anti-roll bar drop link bracket.

Anti-Roll Bar

14. At least one of the lower wishbones must be removed before the ARB may be withdrawn.

Release the anti-roll bar drop links from the ARB noting that the link assembly is symmetrical end to end.

Note that the drop link ball pin self locking nuts should be discarded and renewed for re-assembly. Re-

lease the two bolts securing each of the two ARB pivot clamps to the chassis brackets and withdraw the

anti-roll bar.

Reassembly

Re-assemble the suspension in reverse order to disassembly with the following notes:

If the car suffers a suspension impact sufficient to damage a wheel rim, careful attention should be paid

to all related suspension components, and replacement parts fitted in any cases of doubt.

Smear the shank of each pivot bolt with PBC grease to inhibit corrosion and facilitate subsequent servic-

ing, but do not allow grease contamination of the threads.

Where bolts are threaded into captive nuts with no secondary locking mechanism, apply a suitable thread-

locking compound. If separate self-locking nuts are used, assess the locking torque and renew the nuts

in any case of doubt. The ARB drop link ball pin self locking nuts should always be renewed.

Take care to match mark and refit the eccentric cam adjusters on the lower wishbone pivots in their original

settings to facilitate subsequent geometry checking and adjustment.

Lubricate the rubber type anti-roll bar mountings with rubber grease on assembly.

Refit the plastic bung into the steering arm counterbore to prevent corrosion of the ball joint fixing.

The damper body is provided with three location grooves for the circlip retaining the spring lower seat.

Use the middle position for standard ride height setting. Use spring compressor clamps to assemble the

spring/damper/top mounting bracket (spring close coils lowermost), before fitting the complete assembly

to the car. Do not omit the spring top seat cushion.

Pump the brake pedal to reposition the pads before driving the car.

The Service Schedule specifies that the security of the front and rear suspension is checked at each service.

For cars used on race tracks, or in similar conditions, suspension components and torque checks should be

carried out between sessions. This operation requires that all the principal suspension pivot bolts are torque

checked, noting the following points:

Where a bolt is tapped into a housing or weldnut, and relies on a thread locking compound for security, it

is important to appreciate that if the bolt is disturbed, the locking compound must be re-applied. The following

procedure should be adopted for all such fixings:

Check the torque of the fixing.

If the specified torque is attained without the fixing being disturbed (moving), take no further action.

If the bolt moves, the locking action of the thread adhesive will have been compromised. Remove the

bolt completely, clean off all old adhesive using a wire brush and acetone, and apply new adhesive as

specified.

Refit the bolt and tighten to the specified torque.

If for any reason a bolt is found to have become loose, and the car has been operated for any period in

this condition, the bolt should be renewed as a standard precaution and related components carefully

inspected for hole ovality, undue stress or wear.

Torque Settings: Nm

Upper and lower wishbone pivot bolts 86

Upper and lower swivel joints to hub carrier 86

Track rod end to steering arm 45

Damper to lower wishbone bracket 135

Damper to top anchor bracket 86

Damper bracket to lower wishbone 45

Spring/damper upper anchor bracket to chassis 45

Hub bearing unit to hub carrier 70 + Permabond A130

Brake calliper to hub carrier 86 + Permabond A130

Anti-roll bar alloy mounting clamps to chassis 45

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