22 · Diagnostics

Poor braking action

Make: Fiat
Model: 500 Factory Service Manual
Year: 2007–2024
Section: Brakes › Poor braking action

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Fault diagnosisPoor braking action

POOR BRAKING ACTION

1.2 8v, 1.3 Multijet, 1.4 16v

As the pressure exerted on the brake pedal increases, there is no noticeable corresponding braking action

0	PRELIMINARY CHECKS	All OK	Problems encountered	Operation
		Test results
	First of all, check that the tyres are the correct type, in good condition and correctly inflated	Move on to Step 1	1. Pressure not correct. 2. Tyres unsuitable or worn	1. Make sure tyres are inflated to the correct pressure. 2. Replace the tyres.
1	BRAKE FLUID LEAK CHECK	All OK	Problems encountered	Operation
	Visually check: The level of the brake fluid in the reservoir; No fluid leaks from the brake pump, the pipes or the system connectors.	Move on to Step 2	Leaks in the system.	Tighten the connectors or replace the damaged parts
2	CHECK USING DIAGNOSTIC EQUIPMENT	All OK	Problems encountered	Operation
	Connect the Examiner diagnostic equipment to the diagnostic socket. Check that there are no faults in the ABS control unit.	Move on to Step 3	1. Error detected in the control unit. 2. No communication with the control unit.	1. Continue following the instructions on the diagnostic equipment 2. Restore: Connection between the ABS control unit and the diagnostic connector; ABS control unit supply See E7020 ABS
3	ACTIVE DIAGNOSIS WITH DIAGNOSTIC EQUIPMENT	All OK	Problems encountered	Operation
	Keeping the Examiner diagnostic equipment connected carry out the active diagnosis of: Pump motor; Solenoid valves.	Move on to Step 4 for the 1.4 16v engine type Move on to Step 7 for the 1.2 8v and 1.3 Mjet 16v versions	Fault detected in the pump or in a solenoid valve.	Replace the electrohydraulic unit - ABS electronic control unit Op. 3340A12 ABS HYDRAULIC AND ELECTRONIC CONTROL UNIT - R.R.
4	PAD TYPE AND SURFACE CHECK	All OK	Problems encountered	Operation
	Check: the condition of the pad braking surfaces; type of pads.	Move on to Step 5	1. Brake surfaces vitrified or with traces of grease, oil or water 2. Front pads damaged or not the recommended type 3. Rear pads damaged or not the recommended type.	1. Clean again, check and remove the causes of the fault 2. Replace the front pads Op. 3310A60 FRONT BRAKE PADS - REPLACE 3. Replace the rear pads Op. 3310B60 REAR BRAKE PADS - REPLACE - INCLUDES HANDBRAKE ADJUSTMENT IF NECESSARY
5	DISC CHECK	All OK	Problems encountered	Operation
	Check the condition of the brake discs.	Move on to Step 6	1. Front discs worn or damaged. 2. Rear discs worn or damaged.	1. Replace the front discs Op. 3310A50 FRONT BRAKE DISCS - R.R. 2. Replace the rear discs Op. 3310B50 REAR BRAKE DISCS - R.R.
6	BRAKE CALIPER CHECK	All OK	Problems encountered	Operation
	Check the condition of the front and rear brake caliper control pistons.	Move on to Step 9	1. Front calliper pistons worn or seized. 2. Rear caliper pistons worn or seized.	1. Replace the front brake callipers Op. 3310A32 FRONT BRAKE CALIPERS - R.R. 2. Replace the rear brake callipers Op. 3310B34 REAR BRAKE CALIPERS - R + R - INCLUDES HANDBRAKE ADJUSTMENT
7	CHECK THE WEAR OF THE FRICTION SEGMENTS	All OK	Problems encountered	Operation
	Check the wear of the friction segments through the openings in the brake back plate or the drum.	Move on to Step 8	Friction segments worn.	Brake shoe replacement.
8	CHECKS ON DRUM	All OK	Problems encountered	Operation
	Proceed with dismantling the drum to check the operation of the cylinder(s) checking the operation of the pistons.	Move on to Step 9	Incorrect operation of cylinder.	Replace the cylinder Op. 3320B20 REAR BRAKE SHOE CYLINDER (ONE) LEFT OR RIGHT - REPLACE.
9	VACUUM PIPE CHECK	All OK	Problems encountered	Operation
	Check that the vacuum pipe is correctly fitted/in good condition.	Move on to Step 10	1. Pipe not fitted correctly or bent. 2. Pipe damaged.	1. Refit correctly. 2. Replace vacuum pipe Op. 3330D24 VACUUM PIPE FOR BRAKE SERVO - R+R
10	BRAKE SERVO SINGLE-ACTING VALVE CHECK	All OK	Problems encountered	Operation
	Check that the brake servo single-acting valve is working properly.	Move on to Step 11	Single-acting valve not working properly.	Replace the single-acting valve Op. 3330D20 SINGLE-ACTING VALVE FOR BRAKE SERVO - R+R
11	BRAKE SERVO CHECK	All OK	Problems encountered	Operation
	Check that the brake servo is working properly by carrying out the See Test 3330DA CHECK ON OPERATION OF VACUUM PUMP AND VACUUM CIRCUIT FOR BRAKE SERVO	Move on to Step 12 for the 1.3Mjt 16v engine type Move on to Step 13 for all versions	Brake servo not working properly.	Replace brake servo Op. 3330D02 BRAKE SERVO/BRAKE PUMP ASSEMBLY - R.R.
12	ENGINE VACUUM CHECK	All OK	Problems encountered	Operation
	Check the vacuum circuit reading	Move on to Step 13	Vacuum figure not correct.	Replace the brake servo vacuum unit Op. 3330D30 VACUUM UNIT - R+R
13	FLEXIBLE BRAKE PIPES AND BLEEDING CHECK	All OK	Problems encountered	Operation
	Visually check for kinks or restrictions in the brake pipes. Bleed the system Op. 0010T65 HYDRAULIC BRAKE SYSTEM - BLEED AIR and check that fluid emerges evenly from the bleed screws.	End of diagnosis	Bends or constrictions present, the fluid does not come out evenly.	Replace the section of pipe affected by the problem.

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Parts & tools for this job For 2007 Fiat 500

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