Clutches

1
Clutches
2
Basic purpose

• Used to disengage engine from input shaft
• Flywheel
• Bolted to crankshaft
• Provides surface for clutch disc to work on
• Clutch disc
• Splined to trans. input shaft
• Fits between flywheel and pressure plate

3
Basic purpose

• Pressure plate
• Bolted to flywheel
• Applies squeezing pressure to disc
• Acted on by throw out bearing

4
Flywheel

• Acts as engine balancer
• Works with crank balancer to smooth out firing
  pulses
  
• Some will be balanced to engine
• Adds inertia to engine rotation
• Works as heat sink for clutch
• Ring gear for starter engagement
• Some vehicles have dual mass flywheel

5
Flywheel service

• Visually inspect for hot spots, grooves, scoring
  and cracks
  
• Check with dial indicator for runout and crank
  end play
  
• Most flywheels can (should) be resurfaced
• Must remove dowel pins
• Inspect ring gear
• Flywheel should be marked before removing to
  maintain balance

6
Clutch disc

• Friction material disc splined to input shaft
• Friction material may contain ASBESTOS
• Friction material can be bonded or riveted
• Friction is attached to wave springs
• Most have torsional dampener springs
• Normal wearing component
• Normally a worn out disc will cause slipping

7
Clutch disc service

• Inspect for wear similar to brake pads
• Common to have loose or broken springs
• Common failure due to oil contamination
• Must find cause BEFORE repair
• Normally purchased in kit containing pressure
  plate, disc, throw out bearing
  
• Clutch disc will normally have a flywheel side
• Disc must be centered with clutch alignment tool
  before pressure plate bolted down

8
Pressure plate

• Provides clamping pressure to disc
• Works like spring loaded clamp
• Bolted to _________________
• Can use Belleville spring acted on by T-O
  bearing
  
• Can use coil springs and levers acted on by T-O
  bearing

9
Pressure plate service

• Mark relation to flywheel if reused
• Remove bolts slowly in criss-cross pattern
• Inspect fingers for parallelism, cracking or
  uneven wear
  
• Inspect friction surface for hot spots, cracks
  etc and with straight edge for warpage
  
• Must be torqued to specs and in sequence
• Uses hard bolts

10
Release/ throw out bearing

• Acted on by clutch fork - acting on p-plate
• Moves toward flywheel when pedal pushed
• Slides on front portion of transmission called
  bearing retainer
  
• Normally not in contact with p-plate until pedal
  pushed

11
Release bearing service

• Very common failure - isolated by lightly
  applying clutch and listening
  
• Inspect for looseness or roughness
• Most are sealed but some were lubeable
• Clutch fork must be lubed at pivot point and
  bearing contact points
  
• Bearing retainer and input shaft should be lubed

12
Pilot bearing / bushing

• Used on some cars
• Supports front of trans input shaft
• Can be needle bearing or bronze bushing
• May be part of clutch kit

13
Pilot servicing

• Should always be changed with clutch
• Can be isolated by applying clutch in gear
• Special pullers may be used for removal
• Can be removed with grease
• Should be lightly lubed on installation

14
Clutch linkage

• Can be operated by cable, rods or hydraulics
• May be automatic or manually adjusted
• Hydraulic will have a master and slave cylinder
• Will use brake fluid for hydraulic action
• Will need bleeding with repairs

15
(No Transcript)