General description

Clutch

Early cars

Later cars

Clutch pedal . .

Master cylinder

Slave cylinder

SECTION E

THE CLUTCH

SECTION E

THE CLUTCH

Section

E.I

E.5

E.2

E.3

E.4

Section

E

E

B 1712

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IIIIi

II

MPONENTSCLUTCH COTHE (Early Cars)

MPONENTSCLUTCH COTHE (Early Cars)

11. Nut.

12. Tab washer. assembly.. and capRelease beanng13.

.ng retainer.14. Bean

Driven plate.15.

16. Linings.

17. Rivets.

18. Set screw.

19. Washer.

DescriptionNo.DescriptionNo. ICover assemb y.1.

2 Pressure plate.

. plate stud .3. Pressure

4. Washer.

Thrust spring.5.

t spring cup.6. Thrus

Thrust plate.7. .

t plate retainer .8. Thrus

Release lever.9. . plate.lever bean ng10. Release

THE CLUTCH EGENERAL DESCRIPTION

The clutch is a Borg & Beck single dry-plate typeoperated hydraulically. A steel cover bolted to theflywheel encloses the driven plate, the pressure plate ,the pressure springs, and the release levers. The drivenplate, to which the friction linings are riveted, incorporatessprings assembled around the hub to absorb power shocksand torsional vibra tion. The pressure springs force thepressure plate against the friction linings, gripping thedriven plate between the pressure plate and the engineflywheel. When the clutch pedal is depressed the releasebearing is moved forward against the release plate, whichbears against the th ree release levers. The oute r or shorterends of the release levers engage the pressure plate lugs ;pressure applied by the release bearing causes the pressureplate to be pulled away from the driven plate , compressingthe pressure springs which are assembled between thepressure plate and the clutch cover. As the frictionlinings wear, the pressure plate moves closer to the fly­wheel face and the oute r or shorter ends of the releaselevers follow. This causes the inner or longer ends of thelevers to travel farther towards the gearbox and decreasesthe clearance between the release lever plate and therelease bearing. This is automatically compensated unlessthe master cylinder has been disturbed.

When the clutch pedal is depressed, fluid pressure istransmitted through the master cylinder to the slavecylinder mounted on the clutch housing, moving theslave cylinder piston and push-rod. As the push-rod is

. connected to the lower arm of the clutch withdrawallever, thereby the clutch is released. The push-rod isnon-adjustable.

The correct amount of free movement between themaster cylinder push- rod and piston is set dur ing erectionof the vehicle and should never need alteration .

In the event of the adjustment having been disturbedreset the effective length of the rod connec ting thepiston to the pedal until the pedal pad can be depressedapproximately -A in. (4 mm.) before the piston beginsto move. The clearance can be felt if the pedal is depressedby hand. It is very important that the push-rod shouldhave a minimum free movement of n in. (.g mm.) beforethe piston starts to move.

Section E.lCLUTCH

(Early Cars)Removing

and torsional vibration. The' pressure 'springs fo~ce thepressure plate against the friction linings, gripping thedriven plate between the pressure plate and the engineflywheel. When the clutch pedal is depressed the releasebearing is moved forward against the release plate, whichbears against the th ree release levers. The outer or shorterends of the release levers engage the pressure plate lugs ;pressure applied by the release bearing causes the pressureplate to be pulled away from the driven plate , compressingthe pressure springs which are assembled between thepressure plate and the clutch cover. As the frictionlinings wear, the pressure plate moves closer to the fly­wheel face and the outer or shorter ends of the releaselevers follow. Th is causes th e in ner or Io n oe r end s of the

Detach the retammg springs from the release leverplate and remove the springs and plate. Place the toolbase plate on a flat surface . Select th ree spacing washersfor the particular clutch and place them in positionon the base plate.

Position the clutch on the three spacing washers sothat the holes in the clutch cover al ign with the tappedholes in the base plate with the release levers as close tothe spacing washers as possible. Insert the tool set screws,tightening them a little at a time in a diagonal patternuntil the cover is firmly and evenly secured to the baseplate. This is most impo rtant if the best results are to beachieved.

Knock back the tab washers and remove the should erstud adjusting nut s. Lift off the washers, bearing plates,and release levers.

Unscrew the set screws securing the clutch cover to thebase plate in a diagonal pattern, releasing the pressureon the clutch springs gradually and evenly. Lift off thecover and remove the pressure springs.

Clean the clutch part s carefully. If the linings are tobe used again they should not be allowed to come incontact with cleaning fluids.

Examine the friction linings for wear or loose rivetsand check the driven plate for uneven or worn splines,distortion, or signs of fatigue cracks.

It is essential to install a complete driven plateassembly when renewal of the friction surfaces is required.If the facings have worn to such an extent as to warrantrenewal, then slight wear will have taken place on thesplines and also on the torque react ion springs and theirseatings. The questio n of balance and concentricity isalso involved . Unde r no circumstances is it satisfactoryto repair or rectify fault s in clutch driven plate centres,and we do not countenance this as manufacturers.

Examine the mach ined face of the pressure plate; ifthis is badly grooved and rough, the surface may bereground until the grooves disappear.

Examine the machi ned surface of the release lever plate.If this is badly groo ved, renew the plate. A new platewill also be necessary if the surfaces on the reverse sideof the plate, which are in contact with the tips of therelease levers, are worn down .

Examine the tips of the release levers which bear onthe back of the release lever plate. A small amount ofworn flat surface is permissible, but if this is excessivethe lever should be renewed. Check for excessive wearin the groove in which the fulcrum bears . If the metalhere has worn at all thin, the lever must be renewed asthere is a dan ger of it breaking under load , with disastrousnotes III Hie oase plate wun me release rever s a s \,;w:sc tu

the spacing washers as possible. Insert the tool set screws,tightening them a little at a time in a diagonal patternuntil the cover is firmly and evenly secured to the baseplate. This is most impo rtant if the best results are to beachieved.

Knock back the tab washers and remove the should erstud adjusting nut s. Lift off the washers, bearing plates,and release levers.

Unscrew the set screws securing the clutch cover to thebase plate in a diagonal pattern, releasing the pressureon the clutch springs grad ually and evenly. Lift off thecover and remove the pressure springs.

Clean the clutch parts carefully. If the linings are to

E THE CLUTCH

Fig. E.1

The clutch unit in section (early cars)

1. Flywheel.2. Holding screw.3. Driven plate.4. Cover.5. Thrust spring.6. Clearance ·0625 in. (l'58 mm.),7. Graphite release bearing.8. Release bearing cup.9. Release bearing carrier.

10. Release lever plate.

1

2345

1011

]2

131415

16

1718

11. Lever retainer andanti-rattle spring.

12. Release lever.13. Knife-edge fulcrum.14. Tag lock washer.15. Stud.16. Adjusting nut.17. Bearing plate.18. Pressure plate.

Repeat the procedure to ensure that the release leversare finally seated, and gauge once more. Remove thecentre pillar, distance piece, and height finger and securethe adjusting nuts. Fit the release lever plate on the tipsof the release levers and secure it by the three retainingsprings. Release the tool set screws in diagonal sequence alittle at a time, relieving pressure slowly and evenly.Remove the clutch assembly from the base plate .

RefittingRefitting is a reverse of the remo val proce dure. Use

Service tool 18G 139 for clutch centralization.

Section E.2

CLUTCH PEDALRemoving

Working beneath the bonnet, disconnect the clutchand brake pedal levers from the maste r cylinder push-rodsby removing the spring clips and withdrawing the clevispins. From within the car, remove the nut and springwasher and withdraw the fulcrum pin ; note that a distancepiece separates the two pedals. The pedals can now beremoved.

The pedals together with the master cylinder assemblycan be removed as one unit. This operation is describedin the maste r cylinder removal section.

RefittingWhen refitting reverse the removal procedure.

Section E.3

ReassemblingParts not being replaced by new ones must be refitted

in their original positions .Reassembly is the reverse of the dismantling pro cedure.

Adjusting the clutchThe clutch must now be adjusted, still using the clutch

assembly tool. With the clutch bolted to the tool baseplate, as on completion of assembly, proceed as follows.Screw the actuator into the base plate and pump thehandle a dozen times to settle the clutch mechanism .Remove the actuator. Screw the tool centre pillar intothe base plate and select a distan ce piece, as shown onthe chart. Place the distance piece over the centre pillarwith its recessed face downwards. Place the gauge heightfinger over the centre pillar. Adjus t the height of the

1 .. .. . •

8

9

1011

]2

131415

16

1718

MASTER CYLINDERConstruction

The maste r cylinder caters for operation of bothbrakes and clutch. It has two bores side by side and,except for the fact that one has no check valve, each boreaccommodates normal master cylinder parts. The borewith the check valve serves the brakes, the other servesthe clutch slave cylinder.

RemovingThe following removal procedure allows the with­

drawal of the master cylinder unit complete WIth clutchand brake pedals.

NOTE.-Before disconnecting the master cylinderascertain, for assembly purposes, which bore communi­cates with the clutch slave cylinder.

RefittingRefitting is a reverse of the remo val proce dure. Use

Service tool 18G 139 for clutch centralization.

Section E.2

CLUTCH PEDALRemoving

Working beneath the bonnet, disconnect the clutchand brake pedal levers from the maste r cylinder push-rodsby removing the spring clips and withdrawing the clevis_! ..__ 'T':"' . _ .~","1_~_ ~1 .._ .L -. _ ....... _ .....~ __~__

THE CLUTCH E

1. Filler cap.2. Fixing screw.3. Shakeproof washer.4. Tank cover.5. Tank cover gasket.6. Cylinder barrel and tan k.7. Valve (brake bore only).

14. Gasket.15. Boot fixing plate.16. Fixing washer .17. Shakeproof washer .18. Boot.19. Push rod.20. Push rod adjus ter.

7B. 2 7S88

4

5

6

9/3 12 11 10Fig. £.2

Master cylinder (exploded)8. Return spring.9. Spring retainer.

10. Main cup.11. Piston washer.12. Piston.13. Secondary cup.

1820 19

SLAVE CYLINDER

If no further maintenance is necessary, remember tobleed the system.

Section E.4

20 19 18

DismantlingDisconnect each pedal from its master cylinder push­

rod by removing the spring clips and withdrawing theclevis pins.

Remove the bolts securing the master cylinder unit toits mounting plate and withdraw the complete unit .

Remove the set screws securing the boot fixing plateConstructionto the master cylinder body.

Detach the fixing plate from the master cylinder, The cylinder is bolted to the under side of the clutchand remove the boots and push-rods . housing and comprises a piston, rubber cup, cup filler,

spring, push-rod, and bleeder screw.Remove the common filler cap and drain the fluid intoa clean container. Removing

Withdraw the piston, piston washer, main cup, spring Place a receptacle to catch the fluid and remove theretainer, and the return spring. pipe union on the slave cylinder. Remove the split pin

Remove the secondary cup by stretching it over the and clevis pin from the clutch withdrawal lever yoke.end flange of the piston. Remove the bolts securing the cylinder to the clutch

Examine all parts, especially the washers, for wear or housing and lift off the slave cylinder assembly.,t;",t"....;"., ",.,,1 .. 0 ......1"'''0 n,;th .,on, ...... " ....o Ulh o ...,. npl"e..£."~_~ y-:..

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E

13

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THE CLUTCH COMPONENTS(Later Cars)

10

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14

r H ~ _ ~ ~ _ H _.HHH • • H _ _ ~ H •••H""+-1

i iitI:

it1•

It

ItI:

4. Eyebolt.

5. Eyebolt nut .

1. Clutch assembly.

2. Thrust spring.

3. Release lever retaine r.

8. Release lever.

9. Bearing thr ust plate .

10. Pressure pla te.

11. Anti-rattle spring .

No . Des cription

12. Release bearing.

13. Retainer .

14. Driven plate assembly.

15. Clutch to flywheel screw.

16. Spring washer .

DescriptionNo.

7. Strut.

Descript ionNo .

6. Release lever pin .

THE CLUTCH COMPONENTS(Later Cars)

'It

ItIt

THE CLUTCI-I E

'3141"

F-----~

G-----~

-91ll*=3-

A-·-----------.J~~

B - - - - -C--- - - - - - - --------

D-------I~~

E------.;.;f lll.

op

RemovingRemove the gearbox and the clutch assembly as

described in Sections F and A respectively.

CLUTCH(Later Cars)

Section E.5

ReassemblingReassembling is the reverse of the removal procedure .

RefittingFor refitting reverse the removal procedure. The clutch

hydraulic system should always be bled after an overhauloperatio n.

BleedingFill the master cylinder reservoir with the recommended

fluid and attach a rubber tube to the slave cylinder bleedvalve; immerse the open end of the tube in a cleanreceptacle containing a small amount of fluid. With asecond operator to pump the clutch pedal, open the bleedscrew on the slave cylinder approximately three-quartersof a turn ; at the end of the down stroke on the clutchpedal close the bleed screw before allowing the pedalto return to the 'off' position.

Continue this series of operation until clear fluid freefrom air bubbles is delivered into the container.

Fig. EA

A section through the clutch (later cars)

DismantlingThe clutch tool18G 99 A proves an efficient and speedy

means of dismantling, reassembling, and adjusti ng theclutch with a high degree ofaccuracy. The tool is universaland a chart detailing the sizes of spacing washers anddistance pieces for particular types of clutch is pro videdon the inside of the metal container lid.

Consult the code card to determine the correct spacersfor the particular clutch. Place the spacers on the baseplate in the positions indicated on the code card andplace the clutch on the spacers. Screw the actuator into

A. Flywheel.B. Securing bolt.c. Driven plate.D. Clutch cover.E. Thrust coil spring .F. Release bearing cup.G. Graphite release bearing.H . Release plate.

I. Lever retainer sprin g.J . Release lever.K. Anti-rattle spring .L . Adjusting nut .M. Eyebolt.N . Floating pin (release lever).o. Strut.P. Pressure plate.

Reassembling

the central hole in the base plate and press the handl eto clamp the clutch . Screw the set bolts firmly into thebase plate . The clutch can now be compressed or releasedas required.

Compress the clutch with the actuator and removethe adjusting nuts gradually to relieve the load of thethrust springs. Lift the cover off the clutch and carryout whatever additional dismantling may be necessary.

Fill the maste r cylinder reservoir with the recommendedfluid and attach a rubber tube to the slave cylinder bleed F-----_~valve; immerse the open end of the tube in a clean G------~

receptacle containing a small amount of fluid. With a -t~ti3~-II!_~t==~B-second operator to pump the clutch pedal, open the bleedscrew on the slave cylinder approximately three-quartersof a turn ; at the end of the down stroke on the clutchpedal close the bleed screw before allowing the pedalto return to the 'off' position .

Continue this series of operation until clear fluid freefrom air bubbles is delivered into the container.

SECTION Ea

THE CLUTCH

The information given in this Section refers specifically to the Sprite (Mk. IV) and Midget (Mk, Ill)and must be used in conjunction with Sectiou E.

Ea

Clutch assembly

Master cylinder

SECTION Ea

THE CLUTCH

Section

Ea.!

Ea.2

Ea THE CLUTCH

1- ------2

4 ---'-------~-------~~5~6

7

14

Fig. Ea.l

A section through the clutch

1. Flywheel. 8. Release bearing.2. Clutch securing bolt. 9. Pressure plate.3. Spring washer. 10. Driven plate.4. Cover. 11. Dowel.S. Diaphragm/spring. 12. Release lever.6. Annular rings. 13. Rubber boot .7. Release plate. 14. Slave cylinder.

Section Ea.1

-~ --C-....:...-- ---

7

B94 39

(5) Rotate the release bearing spring retainers through900 and withdraw the bearing from the withdrawallever fork.

Inspection(6) Examine the clutch driven pla te facings for wear

and discoloration. If the facings are worn or aredarkened to the extent that the grain of the facingmaterial cannot be clearly disti nguished the drivenplate must be renewed.

(7) Inspect the splines, springs, and spring pockets inthe dri ve plate for wear, and renew the driven plateif necessary, do not attempt to repair or rectifyfaults in the driven plate centre. Excessive wear ofthe driven plate spIines may be due to misalign­ment and the flywheel should be checked for trueusing a dial indicator ; the reading should not varymore than ·003 in . (,07 mm.) anywhere on the fly­wheel face.

(8) Examine the pressure plate and diaphragm springfor signs of overheating, if there is evidence ofoverheating the complete clutch cover assemblymust be renewed.

(9) Check the release bearing for excessive wear, andrenew if necessary.

Refitting(10) Position the driven plate assembly on the flywheel

with the long side of the hub towards the flywheel.(11) Centralize the driven plate by inserting tool

18G 139 through the splined hub and entering thepilot end of the tool into the spigot bearing of thecrankshaft.

(12) Locate the clutch cover assembly on the flywheeldowels, screw in the securing bolts, and tighten thebolts a turn at a time in diagonal sequence to thetorque figure given in 'GENERAL DATA'.

(13) Remove the clutch centralizing tool.(14) Fit the release bearing to the withdrawal lever fork

and ensure that the spring retainers are correctlylocated.

(15) Refit the gearbox to the engine taking care that thegearbox is supported during the refitting, to avoidstrain on the first motion shaft, and distortion ordisplacement of the clutch components.

(16) Fit the starter motor.(17) Refit the engine and gearbox assembly (Section

Aa.9 (23) to (26» .

..dark;Ded to the extent that the grain of the facingmaterial cannot be clearly disti nguished the drivenplate must be renewed.

(7) Inspect the splines, springs, and spring pockets inthe drive plate for wear, and renew the driven plateif necessary, do not attempt to repair or rectifyfaults in the driven plate centre. Excessive wear ofthe driven plate spIines may be due to misalign­ment and the flywheel should be checked for trueusing a dial indicator; the reading should not varymore than ·003 in . (,07 mm .) anywhere on the fly­wheel face.

(8) Examine the pressure plate and diaphragm springfor si ons of overheatj no. if t here is evirlence of

THE CLUTCH

I ----~~'{ (

2-~

Fig. Ea.2

A section through the master cylinder

o

130 0 0 85

Ea

1. Filler cap.2. Reservoir.3. Body.4. Spring.

5. . Spring retainer.6. Main cup.7. Piston washer.8. Piston .

9. Secondary cup.10. Dished washer.11. Circlips.12. Rubber boot.13. Push-rod.

(4) Unscrew the two bolts securing the master cylinderto the pedal box and remove the master cylinder.

Dismantling(5) Remove the filler cap and drain the fluid.(6) Detach the rubber boot from the bod y and slide it

up the push-rod.(7) Remove the circlip retaining the push-rod, and

withdraw the push-rod complete with the rubberboot and dished washer.

(8) Withdraw the piston complete with the secondarycup, the piston washer, main cup, spring retainer,and spring from the body.

(9) Remove the secondary cup from the piston bycarefully stretching it over the end of the pistonusing only the fingers.

distortion, or any other signs of deterioration.Renew all worn, damaged, or suspect parts.

Reassembling(12) Dip all the internal components in the recommend­

ed clutch fluid and assemble them while wet.(13) Stretch the secondary cup over the piston with the

lip of the cup facing towards the head of the piston.When the cup is in its groove work round itgently with the fingers to ensure that it is correctlyseated.

(14) Fit the spring retainer into the small diameter endof the spring and insert the spring into the body,large diameter end first.

(15) Fit the main cup, cup washer, piston, and push-rod.When fitting the cups carefully enter the lip edgeof the cups into the barrel first.

(16) Fit the circlip and rubber boo t.

o