Fiat 500

CLUTCH SERVICING INSTRUCTIONS

This also frees the driven plate.

To install clutch on flywheel, use as a guide flywheel locating dowels.

Prior to tightening down clutch mounting screws, align driven plate.

(pic. installing the clutch on flywheel using pilot to center the driven plate)

Pilot Bushing.

Whenever clutch unit is disassembled, it is es­sential to check that pilot bush on crankshaft for,

- clutch shaft rear support

- is not damaged or ex­cessively worn.

Clutch shaft tang on bush end must also be found in good condition.

Max. clearance between clutch shaft tang and bush must not be greater than .0059" (0,15 mm), otherwise pilot bush must be replaced.

(pic. clutch assembly installed on engine)

Disassembly.

Unhook the withdrawal lever carrier ring springs and take out the ring.

Unscrew the withdrawal lever fixing nuts on bolts and remove the levers and washers; slacken gradually the three T-handles to relieve pressure of clutch springs.

Next, take off clutch cover, springs and lever mounting bolts.

(Pic.location dowels on flywheel for clutch centering)

Pressure Springs.

When servicing the clutch, always check springs for perfect efficiency. In case springs are exces­sively weak - i. e., the spring length of .9646 (24,5 mm), corresponding to the actual assembly value, is obtained with a load of less than 43 lbs (19,5 kg) - replace the springs.

(Pic. pressure spring specifications)

Withdrawal Lever Carrier Ring Retain­ing Springs.

The length of closed springs, under rated clutch load, is .7677' (19,5 mm), while the length of ex­panded springs (under a load of 4.85 .44 lbs -2,2 ± 0,2 kg) should be 1.1811" (30 mm). If an excessive weakening of springs is noticed, replace the springs.

(Pic. withdrawal lever carrier ring retaining spring specifications)

Withdrawal Levers.

Check the withdrawal levers and their bolts for excessive wear, and replace if necessary.

Thoroughly clean the inside end of levers, so to remove any sign of contact with carrier ring.

PRESSRE SPRING SPECIFICATIONS

PART Number	WIRE Dia	OUTSIDE Dia	WORKING COILS No.	TOTAL COILS No.	HEIGHT, FREE SPRING	SEATED SPRING
						Length	Corresponding Load	Minimum Load
891312	.1102" (2,8 mm)	.9134” (23,2 mm)	6	7.5	1.6417" (41,7 mm)	.9646" (24,5 mm)	51.8 + 2.6 lbs (23,5 ±1,2 kg)	43 lbs (19.5 kg)

WITHDRAWAL LEVER CARRIER RING SPRING SPECIFICATIONS

PART Number	WIRE Dia.	OUTSIDE Dia.	WORKING COILS No.	TAUT SPRING		SEATED SPRING
				Length	Corresponding Load	Length	Corresponding Load
891319	.0394" (1 mm)	.3740" (9,5 mm)	10.5	.7677" (19,5 mm)	1.1 ±.11 lbs (0,5 ±0,05 kg)	1.1811" (30 mm)	4.85±.44 lbs (2,2 ±0,2 kg)

Pressure Plate.

Check plate for absence of cracks and for per­fect flatness of its contact face with driven plate. Otherwise, clutch will develop noises.

If deformations or nicks found are not too severe, the trouble may either be remedied by a slight lapping on planishing stake or turning of the contact face.

Similarly, check also the flywheel friction surface.

(Pic. clutch assembly with separate driven, viewed from pressure plate side)

Driven Plate.

Whenever clutch driven plate facings are worn, fit new ones. Rivet upsetting must be perfect and rivet heads must be flush with facings, otherwise flywheel and pressure plate working surfaces will be scored.

Check proper balancing and centering of driven plate.

If balance needs correction, grind plate periph­erally on the heavier spots.

Centering checks are easily accomplished by first inserting driven plate on a splined shaft, then verifying with a scriber that, during rotation, out-of-center on sides or warping are not greater than .0118" (0,3 mm).

To prevent rattling: clutch shaft splines should not have any lengthwise clearance in excess of .0039" (0,10 mm) and side clearance of .0118" (0,30 mm) with respect to driven plate hub.

Ensure a free sliding of driven plate on shaft splines, since undue plate drag would cause a grabbing clutch and lead to subsequent gearshift troubles.

(Pic. clutch assembly with separate driven plate)

Assembly and Adjustment.

Proceed as follows:

Place the pressure plate, complete with carrier ring bolts and springs,

Fit the six pressure springs in their respective seats on pressure plate.

Insert the cups on springs and install the cover.

Compress the clutch cover, making sure that the withdrawal lever supporting bolts are properly guided into their holes in cover.

On bolts, install the three withdrawal levers with relevant nuts and washers.

Place the carrier ring on levers and hook up the retainment springs.

Tighten up fully the T-handles and adjust the clearance between the carrier ring and its central shoulder: by means of adjustment nuts, set with­drawal levers stroke to .0039" (0, 10 mm). Check with gauge

Clutch pressure plate and cover must be in­stalled in the same position as before disassembly, not to compromise the balance of the assembly.

(SEE EXPLODED CLUTCH VIEW)