Lotus Service Notes Section QA

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1 CLUTCH SECTION QA Sub-Section Page General Description QA.1 3 Clutch Pedal QA.2 4 Clutch Master Cylinder, Slave Cylinder, Clutch Damper & Hydraulic Lines QA.3 5 Clutch Bleeding Procedure QA.4 8 Clutch Potentiometer QA.5 9 Clutch Assembly QA.6 10 Updated 9 th January 2017 Page 1

2 Clutch System General Layout Friction plate Clutch cover Extension/adaptor Release bearing Fork pivot Release fork NVH attenuator/damper To fluid reservoir Retaining spring Fork gaiter Master cylinder Slave cylinder Hose from chassis to transmission Pipe run along sill q54 Page 2

3 QA.1 - GENERAL DESCRIPTION The Lotus Exige S uses a CMS C500 cast iron flywheel bolted to the rear end of the engine crankshaft, secured with 8 bolts and located by a dowel pin. Sandwiched between the flywheel and crankshaft is a steel plate carrying the starter ring gear, and also secured to the periphery of the flywheel with 6 screws. The driving surfaces of the clutch assembly comprise the rear face of the flywheel, and a corresponding surface on a pressure plate carried by the spring diaphragm clutch cover which is bolted to the periphery of the flywheel. The driven element, constitutes a single, dry, double sided friction plate, splined to the gearbox input shaft, and sandwiched between the flywheel and pressure plate. The diaphragm spring between the clutch cover and pressure plate serves to clamp the friction plate between the pressure plate and flywheel and provide the drive connection between engine and gearbox. The gearbox input shaft, on which the friction plate is free to slide axially, is 'overhung' from the gearbox, with no spigot bearing in the rear end of the crankshaft. The hydraulic clutch release mechanism uses a master cylinder fixed to the pedal box and operated by the clutch pedal, and a slave cylinder bolted to the left hand side of the clutch housing operating a release fork pivoted on a ball pin inside the housing to apply an axial thrust to the release bearing. The release bearing surrounds the gearbox input shaft and transmits the thrust via a ball bearing race and separate distance piece to the ends of the diaphragm spring fingers. This action releases the clamping action of the spring outer rim, serving to disengage the drive. No routine adjustment of the clutch or release mechanism is required. The clutch slave cylinder is self adjusting, with the 'rest' position of the piston dependent on the thickness, or degree of wear, of the friction plate. As wear of the friction plate takes place, and its thickness is reduced, the slave cylinder piston is pushed progressively further back on the return stroke with a corresponding rise in the reservoir fluid level. Page 3

4 QA.2 - CLUTCH PEDAL Down stop buffer 'Top hat' bushes Clevis pin Clevis pin retaining clip Clutch and brake pedal pivot shaft Clutch potentiometer Clutch pedal Pedal pad The clutch pedal is fabricated from steel plate, with an extruded footpad keyed, rivetted to the bottom of the pedal. Synthetic 'top hat' bushes are used to provide maintenance free articulation on the steel pivot shaft, with a metal bearing inserted into an aperture of the pedal to support the clevis pin controlling the clutch master cylinder yoke and clutch potentiometer actuation pin. Note that the two synthetic bearing rings may be replaced with the pedal 'in-situ', by using a suitable bolt with clamp washers to press the rings into position. Each bush has an outer diameter chamfer at one end to aid insertion. The master cylinders one piece plastic pushrod/mounting yoke is fitted either side of the clutch pedal, retained with a clevis pin which passes through either side of the mounting yoke and secured in place with a metal clip. The master cylinder pushrod is captive in the end of the master cylinder, and uses an integral clevis to connect to the pedal and control the pedal up position as the master cylinder 'tops' out. A downstop buffer is provided on the pedal box flange. Clevis pin Clutch master cylinder Clevis pin retaining clip Return spring Clevis pin bush Clutch pedal Page 4

5 QA.3 - CLUTCH MASTER CYLINDER, SLAVE CYLINDER, CLUTCH DAMPER & HYDRAULIC LINES Reservoir hose Clutch fluid inlet port Upper pedal box housing Hose retaining clip M8 x 25 bolts Outlet pipe quick fit connector adaptor Master cylinder outlet pipe Master Cylinder The clutch master cylinder is mounted on the pedal box. The cylinder is not equipped with its own fluid reservoir, but instead is linked via hose to the adjacent brake fluid reservoir. An adaptor is screwed onto the end of metal clutch pipe allow fitment onto the plastic master cylinders 'quick fit' outlet pipe connection. There is no provision for any servicing of the master cylinder, and if found to be faulty, the unit should be replaced. Removal: 1. Remove the front body access panel, see service notes section BT.2 for further information. 2. Clean the clutch master cylinder and surrounding area with methylated spirit. Clutch master cylinder Note: Take all necessary precautions to guard against contamination of painted surfaces with brake fluid. RHD Vehicles: Carefully remove the brake fluid reservoir, refer to service notes section JM.8 for further information. Release the flanged M8 nuts (2) securing the reservoir bracket to the pedal box extension plinth, torque to 25 Nm and withdraw. There is now sufficient access to the clutch master cylinder. LHD vehicles: There is sufficient space between the brake fluid reservior and the clutch master cylinder that its removal can be carried out with removing the brake fluid reservoir. 3. Disconnect and immediately plug and cap the hose connection to the fluid reservoir. 4. Release the clutch master cylinder output pipe connection by gently pushing the outlet pipe adaptor into the master cylinder and then pushing in the sprung loaded retaining clip on the end of the hose connection to release the pipe/adaptor from the cylinder. Push in 'Quick-fit' connector clip to release outlet pipe 6. From inside the footwell, remove the clutch potentiometer; refer to subsection QA.5 for further information. 7.Release the spring clip securing the clevis pin connecting the master cylinder pushrod/yoke to the clutch pedal and withdraw the pin. 8. Remove the M8 x 25 bolts (2) securing the cylinder to the pedal box and withdraw the cylinder from the pedal box. Connector adaptor Page 5 Updated 6 th July 2016

6 Refitment: Is the reverse of the removal procedure. -- Refit the pedal box fixings and torque to 25 Nm. - Renew the Oetiker clip securing the reservoir hose to master cylinder then refit the hose onto the master cylinder inlet port THE HOSE SHOULD BE PUSHED ONTO THE PORT DRY - DO NOT USE ANY CHEMICALS OR LUBRICANTS TO AID FITMENT AS THIS COULD CAUSE FLUID CONTAMINATION WHICH MAY RESULT IN AN INAFFECTIVE CLUTCH PEDAL. - Refit the outlet pipe adaptor onto the clutch master cylinders 'quick fit' connection. - Bleed the hydraulic system of air, refer to sub-section QA.4 for further information. Slave Cylinder Clutch slave cylinder Damper to bracket M6 x 12 fixing screws (8Nm) Slave cylinder retaining bolts 12Nm Damper bracket fixings to transmission M8 x20 screws (20Nm) Damper bracket Clutch hydraulic line Clutch actuation damper The slave cylinder is secured to the left hand side of the clutch housing by two M8 x 20 screws into tapped holes. The cylinder is protected from radiated heat from the front catalytic converter by an aluminium heat shield, part of which may be bent back to allow improved access to the slave cylinder bleed nipple. A clutch damper is fitted in the fluid line between the flexible rubber hose fixed to the chassis and solid metal pipe to the clutch slave cylinder. The damper contains a flexible diaphragm to smoothen pressure pulsations in the line caused by frequencies generated by the crankshaft that are isolated from rest of chassis via engine mounts etc, but when the clutch pedal depressed the frequency can travel through the clutch cover, release bearing, slave cylinder and through the fluid line up to the clutch pedal. These pulsations give the symptoms of a roaring noise and vibration which can be felt through the clutch pedal when it is depressed at high revs, typically 5000 rpm. Do not attempt to bleed the clutch hydraulic system when the catalytic converter is hot - spilled hydraulic fluid could initiate a fire. Wait until the engine and converter is cool to the touch. Page 6

-- Release the two M8 fixing bolts and withdraw the cylinder. -- Take all necessary precautions to guard against contamination of painted surfaces with brake fluid.

7 To replace the slave cylinder Removal: -- Remove the rear undertray; refer to service notes section AN.2 for further information. -- From underneath the vehicle, disconnect the clutch pipe union at the slave cylinder and immediately seal the open end of the pipe and the cylinder port. -- Release the two M8 fixing bolts and withdraw the cylinder. -- Take all necessary precautions to guard against contamination of painted surfaces with brake fluid. Refitment/replacement: Is the reversal of removal. -- Refit the two M8 bolts securing the slave cylinder to the bell housing, torque to 12 Nm. -- Re-connect the clutch pipe union to the cylinder, torque to 16 Nm. -- Bleed the system of air, refer to sub-section QA.4 for further information. -- Finally, ensure that the heat shield is returned to its original shape in order adequately to protect the slave cylinder and hydraulic line. Hydraulic Pipe Steel pipe to slave cylinder Flexible hose to clutch damper Clutch master cylinder Steel pipe clipped to heater pipe A 2-part rigid steel pipe is used to convey the hydraulic fluid from the master cylinder to the left hand front corner of the engine bay, with different length and profiled pipes being used for LH and RH drive vehicles to allow for the alternative master cylinder positioning. The pipe is routed down the LH 'A' post to run along the outside of the chassis LH main siderail, within the composite sill member, and is supported, together with other pipes and hoses in foam blocks. A flexible hose is used to connect the rear end of the chassis pipe to an NVH clutch damper mounted on the transmission. A short rigid pipe then connects the damper to the slave cylinder. Updated 30 th October 2012 Page 7

8 QA.4 - CLUTCH BLEEDING PROCEDURE Do not attempt to bleed the clutch hydraulic system when the catalytic converter is hot - spilled hydraulic fluid could initiate a fire. Wait until the engine and converter is cool to the touch. If the clutch fluid is to be renewed, or an hydraulic component replaced, the system should be bled of air using the following procedure: Remove the rear undertray - see service notes section AN.2 for further information. Using only a fresh supply of DOT 4 non-mineral type brake fluid, top up the brake/clutch reservoir as necessary - also see service notes section JM.3 for further information. If the reservoir needs topping up, first clean around the cap to reduce the possibility of contamination before unscrewing the cap; it is not necessary to disconnect the level sensor cables. Take suitable precautions to guard against damage to paintwork caused by brake fluid dripping from the level sensor. From underneath the engine bay, fit a suitable bleed tube and container to the slave cylinders bleed nipple then open the nipple. Using conventional manual techniques, or low air pressure applied to the reservoir, bleed the system from slave cylinder bleed nipple in turn until no air bubbles can be seen then tighten the bleed nipple to 5 Nm. Test the operation of the clutch pedal, if the pedal operation is spongy repeat the process until an acceptable pedal action is obtained, Top up the fluid level in the reservoir (but do not overfill) then replace the filler cap securely. Refit the undertray Page 8

9 QA.5 - CLUTCH POTENTIOMETER Clutch pedal travel is monitored by the potentiometer module. The module comprises of a pronged arm which rotates around the main body of the potentiometer body which is fixed in place to the pedal box. The potentiometer bodies relative position on the pedal box is set by an integral locating pin and is further retained in position with an M4 bolt tightened to 4Nm. The potentiometer arm is held in its relative position to the potentiometer body and clutch pedal by the master cylinder clevis pin. Clutch pedal pin Potentiometer Locating pin Retaining bolt Arm Movement of clutch pedal rotates the arm relative to the position of the potentiometer body. Data on clutch pedal position is used by the engine management system for: q68 - Cruise Control operation - Gearchange fuel cut off (To assist rapid smooth gearchanges). - Start inhibit function on specific market vehicles. Please see Service Notes Section EMQ for Diagnostic Trouble Codes (DTC) associated with the clutch potentiometer. Please Note: If Cruise Control is disabled without driver intervention but the service light has not been illuminated check that the potentiometer is secure to the pedal box bracket. Page 9

10 QA.5 - CLUTCH ASSEMBLY The clutch assembly comprises: A. Friction plate (centre plate). B. Clutch cover assembly (pressure plate/ diaphragm spring/cover). C. Bearing adaptor. D. Release bearing. 5 2 A B 1 4 TRANSMISSION SIDE D C 6 3 Clutch cover bolt loosening sequence For access to the clutch assembly, the complete power unit must first be removed from the vehicle and the transmission and engine assembly separated (see service notes sections EM.6 and FK.6. for further information. Clutch Removal: 1. Unless the cover is to be renewed, first match mark the cover in relation to the flywheel prior to removal. 2. Progressively loosen the M8 x 16 bolts (6) in the sequence as shown, to release the clamp load without distorting the clutch cover. 3. Remove the bolts and withdraw the cover from the flywheel dowels and prepare to capture the friction plate which will also be released. Inspection: Clutch cover: Check the surface of the pressure plate for excessive scoring or discolouration through overheating. Check the fingers of the diaphragm spring for excessive wear at the release bearing contact surface and for even height. If the cover is accidentally dropped, the setting or balance of the assembly could be disturbed; replacement of the cover is recommended. Friction plate: Check the cush drive springs for breakage or cracking of the hub. Examine the condition of the friction material for signs of oil contamination, scorching, or any other damage. Measure the depth of material on both sides of the plate from the friction surface to the head of the rivets. The minimum service depth = 0.3 mm. If any of these inspections are failed, or if there was an issue with clutch judder, the friction plate should be renewed. Release bearing & fork: Be aware of the extension/adaptor which may or may not be retained in the release bearing. Unclip the release bearing from the fork, and check the bearing for discernible play, noise or rough feeling and renew if there is any doubt. Check the arm for undue wear on any of the contact surfaces and for cracks. Check the condition of the release fork pivot ball. Flywheel: Check the friction surface of the flywheel for excessive scoring or discolouration through overheating. Using a dial test indicator, measure the axial run-out at the centre of the flywheel friction surface. The maximum runout is 0.15 mm. If necessary, renew the flywheel. Updated 9 th January 2017 Page 10

11 Lotus Service Notes Section QA Spacer ring 3 2 Ring gear 8 6 Flywheel bolt loosening & tightening sequence Ring gear to flywheel retaining bolts Flywheel removal: 1.Using a suitable flywheel holding tool, lock the flywheel ring gear against the engine casing. 2.Progressively loosen the eight bolts securing the flywheel to the crankshaft in the sequence as shown 3.Remove the bolts and withdraw the flywheel and prepare to capture the spacer ring fitted between the ring gear plate and the crankshaft flange. Ring gear removal: 1.Progressively loosen and remove the 6 bolts securing the ring gear to the flywheel. 2.Separate the ring gear from the flywheel. Ring gear refitment: -- Ensure scrupulous cleanliness of the ring gear to flywheel contact surfaces before locating the ring gear against the flywheel. Ensure that the ring gear plate swages face towards the flywheel. -- Fit the ring gear to the rear side of the flywheel. -- Use a suitable alignment tool to ensure the ring gear and flywheel are aligned/concentric before tightening the 6 securing bolts to 30 Nm. Flywheel/ring gear refitment: -- Ensure scrupulous cleanliness of the ring gear to crankshaft contact surfaces before locating the flywheel/ ring gear assembly onto the crankshaft flange. Permabond application -- Fit the assembly to the crankshaft, ensuring the spacer ring is fitted between the ring gear plate and crankshaft, with the dimple on the spacer locating in the crankshaft flange dowel hole. -- Apply a single bead of Permabond A130 along the length of the threads of each of the 8 the flywheel retaining bolts. Page 11 Upda ted 9 th Januar y 2017

12 Lotus Service Notes Section QA Important: The drillings for the flywheel retaining bolt threads pass completely through the crankshaft flywheel mounting flange. It is possible that under running conditions, oil within the engine may travel between the flywheel retaining bolt and flywheel mounting flange threads. Therefore Permabond A130 should be utilised as both a thread lock and sealant to prevent the potential of oil leaking from the engine and onto the flywheel and clutch assembly. -- Refit the bolts and progressively tighten the bolts in a diagonal sequence, locking the ring gear before finally torque tightening to 75 Nm. Clutch Refitment: MISS AN S TR ION SIDE Preparation: On re-assembly, using a suitable automotive clutch and brake cleaner, thoroughly degrease the friction surfaces of the flywheel and pressure plate. ION SIDE 1. Friction plate orientation N TRA SMISS 1.Place the friction plate the correct way against the flywheel (identified by the 'TRANSMISSION SIDE' text on the plate). 2.Use a suitable* alignment tool to position the friction plate centrally to the flywheel. *The alignment tool used must not protrude further than the clutch cover spring fingers. This will ensure that the clutch cover compression tool, (see step 6) will fully compress the clutch cover against the flywheel Using an alignment tool which is too long potentially risks the pressure pad of the compression tool contacting the end of the alignment tool before the clutch cover has made full contact with the flywheel. End of alignment tool not to protrude further than clutch cover spring fingers 3.Fit the clutch cover, positioning it to align the 3 locating dowels on the flywheel with the corresponding holes on the cover. 4.& 5. 4.Apply Permabond A130 thread locking compound to three of the clutch cover retaining bolts. 5.Fit the 3 bolts (by hand only sufficiently to hold the centre plate in position when the alignment tool is removed) to every other retaining hole in the cover to the flywheel, this will retain the cover at 3 equal points. Page 12 Upda ted 9 th Januar y 2017

13 Lotus Service Notes Section QA To ensure that the most uniform spring pressure is applied to the plate, with minimum distortion of the diaphragm fingers, it is essential that a proprietary clutch cover compressor tool is used such as Lotus tool part number T000T1524F. 6.Fit the compressor tool to the flywheel using the remaining 3 fixing points for the clutch cover & Wind in the spindle of the compressor tool until the spindle pressure pad contacts the spring fingers. 8.Tighten the spindle further to progressively reduce the gap between the clutch cover and the flywheel. 9. Continue compression until this gap is reduced to zero. 10.Apply a further 2 complete turns (equivalent to 3mm axial travel) to preload the diaphragm spring before evenly tightening the three clutch cover retaining screws to a final torque of 20 Nm & Unwind the spindle of the compressor tool and then remove the tool from the flywheel. 12. & Apply Permabond A130 thread locking compound to the remaining three clutch cover bolts. 13.Fit the bolts and progressively tightening to 20 Nm. 14.Remove the clutch alignment tool Release bearing and adaptor: 14. Page 13 Upda ted 9 th Januar y 2017

14 15. Ensure that the release bearing is correctly fitted to the release fork by ensuring that the notch in the rear of the bearing is inset of the release fork. 16. Prior to fitment of the clutch fork and release bearing, apply a small amount of Renolit LX EP 2 grease to the forks support peg recess. 17. Apply a small amount of Renolit LX EP 2 grease to the gearbox input shaft collar. Bearing retaining clip located into notch From inside the gearbox bell housing, engage the release bearing around the input shaft collar whilst feeding the opposite end of the fork through the release fork gaiter. q Align the clutch fork recess against the support peg, then push the fork firmly to fully engage the fork on the support peg. 20. Apply a small amount of suitable automotive multipurpose high temperature grease (such as Castrol multipurpose high temperature grease formerly named LMX) over the forward most 10 mm of the splined area of the gearbox input shaft Remove any excess grease that has built up on the chamfer on the input shaft which could contaminate the clutch assembly causing a source of potential clutch judder. 22. Ensure the bearing adaptor is located positively against the clutch release bearing q61 Transmission refitment: Fit the transmission assembly to the engine, refer to service note section FK.6 for further information. f163 Page 14 Updated 9 th January 2017

Lotus Service Notes Section QR

Lotus Service Notes Section QR CLUTCH SECTION QR Sub-Section Page General Description QR.1 3 Clutch Pedal QR.2 4 Hydraulic Release System QR.3 5 Clutch Assembly QR.4 10 Clutch Potentiometer QR.5 15 Updated 9 th January 2017 Page 1 Clutch