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Lotus Evora. Manual - part 45

Lotus Service Notes

Section HI

Illustration of track rod adjustment

Note that in order to preserve the required bump steer characteristic and steering symmetry, the effective

length of each track rod must remain equal; compare dimensions and equalise if necessary before subsequently

adjusting each track rod by a similar amount:

Slacken the rack gaiter outboard clips.

Hold the track rod using the flats provided, and slacken the locknut. Repeat for the opposite side.

Turn each track rod a similar amount. As a guide, turning both track rods by one quarter of a turn will alter

overall toe-out by approx. 2.0 mm.

When adjustment is correct, hold each track rod and tighten the locknuts to 45 Nm. Tighten the rack gaiter

clips.

CAUTION: When slackening or tightening the track rod locknuts, it is important that the torque reaction is re-

sisted using the track rod flats, and that the ball joint itself is not allowed to be stressed.

Track Rod Ends

The track rod end ball joints are sealed for life and maintenance free. If replacement is required;

Remove the ball pin nut and use a ball joint splitter tool to separate the joint from the steering arm.

Unscrew the track rod from the steering rack tie rod, using the locknut as a refitment position guide.

On re-assembly, tighten the ball joint to steering arm nut to 45 Nm, and set the front wheel alignment as

detailed in sub-section CK.2.

Steering Rack Gaiters

The convoluted gaiters sealing each end of the steering rack housing to the tie rods, should be inspected

at service intervals and replaced immediately if found to be torn, cracked or otherwise damaged. The ingress

of dirt or water into the rack housing will cause rapid deterioration of the track rod inner ball joints, rack end

bushes and rack and pinion mechanism, requiring replacement of the complete steering gear.

To replace a gaiter, remove the track rod (see above), release the gaiter clips, and slide the gaiter off the

housing and tie rod. Check for consequent damage or wear and replace the steering gear assembly if neces-

sary. Fit the new gaiter into position, and secure with new retaining clips.

HI.6 - RACK & PINION ASSEMBLY REMOVAL/REPLACEMENT

The steering rack assembly consists of an alloy pinion housing/valve body, and a steel tube through which

the rack is guided. The pinion housing features two solid bushed lugs, which bolt to an extruded alloy bracket,

itself secured to the subframe with four bolts threading into a tapping plate. The non-pinion end is secured by

a 2-bolt clamp and rubber sleeve around the steel tube to a second extruded bracket, secured with two bolts.

Short ball jointed tie-rods from each end of the rack connect, via extended 'track rod ends' to forward facing

steering arms integral with the forged steel front hub carriers.

Note that the only approved repairs or adjustments to the steering rack assembly are the replacement of

the track rod ends, rack housing gaiters, and the pipes connecting the pinion housing to the rack body.

Lotus Service Notes

Section HI

To Remove/Replace Steering Rack Assembly

The steering rack may be removed from the front subframe after first removing the front anti-roll bar with

its mounting brackets.

1. Remove both front wheels, and the front undertray.

2. Release the anti-roll bar from the drop link at each side.

3. At each side, remove the six screws securing the extruded alloy mounting plate to which the ARB clamp

is fixed. Captive threaded inserts are used in the subframe. Withdraw the anti-roll bar assembly from the

car.

4. Remove the nut securing each track rod end to the steering arm, and use a ball joint splitter to separate

the joint.

5. Match mark the pinion shaft against the u/j yoke to aid steering wheel alignment on re-assembly, and

remove the pinch bolt.

6. Slacken the banjo bolts securing the feed and return pipes to the pinion housing, and collect the draining

oil. Removal of the bolts may not be possible at this stage.

7. At each end of the rack housing, remove the two bolts securing the unit to the mounting brackets. With-

draw the pinion shaft from the lower u/j and remove the two banjo bolts as the assembly is withdrawn from

below.

To Re-fit/Replace Steering Rack Assembly

Refit in the reverse order to removal, with the following notes:

Engage the pinion shaft with the column u/j (match marks aligned) as the housing is positioned. Fit and

tighten the u/j pinch bolt to 25 Nm.

Before securing the rack housing, refit the feed and return pipes to the pinion housing using new or an-

nealed washers. Torque tighten M14 (return) to 18 - 25 Nm; M16 (feed) to 25 - 30 Nm.

Torque tighten housing fixing bolts (4 off) to 45 Nm.

Torque tighten track rod end ball pin nuts to 45 Nm.

Torque tighten the anti-roll bar clamp mounting plate to subframe bolts (8 off) to 24 Nm.

Torque tighten the anti-roll bar to drop link fixings to 38 Nm.

Refill the power steering reservoir and bleed the system as detailed in sub-section HI.3

Check and adjust the front wheel alignment as detailed in sub-section CK.2.

Note: If the rack mounting plinths are removed from the front subframe, note that there are shim plates fitted

between the plinths and the subframe top surface in order to control the height of the rack and the bump steer

characteristic. Shim plates are available in thicknesses of 5, 2 and 1mm, with the standard setting being two

2mm shim plates at each position. Torque tighten the plinth to subframe fixing bolts to 45 Nm.

HI.7 - PAS PUMP & TESTING PROCEDURE

The vane type, constant displacement hydraulic pump is mounted on the right hand front of the cylinder

block, and is driven by the automatically tensioned multi-rib auxiliary belt from the crankshaft pulley. To check

for correct functionality, the steering effort may be checked with the engine running and the car stationary:

PAS Pump Test Procedure

Tools required

PAS Pressure Test Gauge Kit - use a universal kit, or Toyota part number 09640-10010

1. Remove the rear clamshell (see Sub-Section BV.6).

Lotus Service Notes

Section HI

2. Check auxiliary drive belt condition and fluid level. With engine idling, turn the steering from lock to lock

several times to raise fluid temperature and check for foaming or emulsification; if necessary, bleed the

system (see Sub-Section HI.3).

3. Remove the banjo bolt connecting the pressure outlet pipe to the PAS pump. Fit the adaptor pipe from

the test kit into the pump, and connect the gauge inlet pipe to the adaptor.

4. Connect the outlet pipe on the gauge to the banjo connector using the union adaptor.

5. Open the gauge valve, and bleed the system of air (see above).

6. With the engine idling, turn the steering from lock to lock several times to raise fluid temperature (70 -

80°C).

7. With the engine idling, close the gauge valve and observe the gauge reading -

Do not keep the valve

closed for more than 10 seconds, or excessive oil heating will occur.

Minimum fluid pressure: 7800 to 8300 kPa (1100 to 1200 psi).

8. With the engine idling, open the gauge valve fully and measure the pressure at engine speeds of 1000

and 3000 rpm.

Maximum difference: 490 kPa (70 psi).

9. With the engine idling and the gauge valve fully open, turn the steering to full lock and measure the fluid

pressure. Repeat for the opposite lock -

Do not keep on full lock for more than 10 seconds, or exces-

sive oil heating will occur.

Minimum fluid pressure: 7800 to 8300 kPa (1100 to 1200 psi).

10. Disconnect the gauge pipes and refit the banjo union to the pump. Bleed the system of air (see above).

HI.8 - PAS PUMP REMOVAL & INSPECTION

The vane type, constant displacement hydraulic pump is mounted on the right hand front of the cylinder

block, and is driven by the automatically tensioned multi-rib auxiliary belt from the crankshaft pulley. The pump

is secured to the engine by two bolts, access to which requires the removal of the rear clamshell.

1. Remove the rear clamshell (see Sub-Section BV.6).

2. Use a syringe to empty the PAS reservoir of oil and reduce potential spillage.

3. Using a 14mm hexagonal socket, turn the auxilary belt tensioner counterclockwise to relieve tension on

the belt, and insert a 5mm rod through the tensioner hole to secure in that position. Mark the direction of

rotation on the belt before unhooking from the PAS pump pulley.

4. Disconnect the reservoir hose from the pump, and plug both hose and pump port.

5. Disconnect the high pressure feed pipe from the pump, and plug both pipe and pump port.

6. Disconnect the harness from the PAS pump pressure switch.

7. The pump is secured to the engine by two bolts, accessible between the spokes of the pulley. Remove

the lower bolt. Unscrew the upper bolt from its threaded boss, but leave in position whilst withdrawing the

pump from the slotted upper lug.

8. Flow Control Valve:

Remove the pressure port union and 'O' ring.

Remover the flow control valve and compression spring.

Lotus Service Notes

Section HI

With the pump port axis vertical, check that the valve (lubricated with PAS fluid) falls smoothly into the

port. If any stickiness is apparent, replace the pump.

Check the valve for leakage: Close off one of the ports in the side of the valve, and apply 450 kPa (65 psi)

of compressed air to the opposite port. No leakage from either end of the valve should be detected.

Measure the free length of the flow control valve spring with a vernier caliper: Minimum = 29.2 mm

Coat the valve with PAS fluid and instal with its spring. Fit a new 'O' ring on the pressure port union, lu-

bricate, instal and tighten to 69 Nm (51 lbf.ft).

9. Vane Pump Mechanism:

Remove the 4 bolts securing the pump rear housing, and withdraw the housing.

Remove the snap ring from the pump shaft and withdraw the pulley and shaft assembly.

Remove the pump rotor with its 10 vanes, followed by the cam ring and pump front plate.

Pull out the shaft oil seal from the front of the housing, and press a new seal into position.

Measure the thickness of each rotor vane: Specification = 1.405 - 1.411 mm

Measure the side clearance between each vane and its rotor slot: Max. clearance = 0.03 mm

Measure the pump shaft diameter and housing bush diameter and determine the oil clearance:

Max. clearance = 0.07 mm

Refit the shaft and pulley assembly, taking great care not to damage the oil seal.

Fit new 'O' rings to the housing and front plate and lubricate with PAS fluid, before inserting the plate into

the housing with the notch on the rear side rim aligned with the notch in the housing.

Fit the cam ring into the housing with the inscribed mark facing rearwards, and the notch aligned with the

notch in the front plate.

Fit the vane rotor onto the shaft and lubricate before sliding the 10 vanes into their slots.

Retain the rotor by installing a new snap ring into the shaft groove.

Fit a new 'O' ring into the groove in the rear cover, and fit the cover to the housing so that the alignment

pin engages into the notches in the cam ring, front plate and pump housing. Fit the 4 retaining bolts and

tighten to 22 Nm.

Check Preload: Fit a M10 x 1.25 x 50mm bolt into the pulley end of the shaft, and apply a torque wrench

to the bolt. Check pump rotation torque; Max. = 2.8 kgf.cm (2.4 lbf.in).

10. If necessary, fit a new PAS pressure switch with lubricated 'O' ring, and tighten to 21 Nm.

11. Before installing the pump, insert the upper bolt through the top lug on the pump housing. Fit the pump

to the engine and secure with the upper and lower bolts. Tighten both fixings to 43 Nm (32 lbf.ft).

12. Plug in pressure switch connector. Fit banjo bolt with two new washers and connect high pressure pipe

to outlet union. Tighten to 50 Nm (37 lbf.ft). Connect the reservoir hose to the pump spigot and secure

the clamp.

13. Refit the auxiliary drive belt to all pulleys, ensuring that the belt ribs are correlty located on each drive

pulley. Rotate the tensioner counterclockwise to relieve tension, and remove the tensioner locking pin.

14. Refill and bleed the PAS system (see above), and check for leaks.

15. Refit rear clamshell (see sub-section BV.6).

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