18 · Diagnostics

F12 Brake pedal stiff

Make: Alfa Romeo
Model: 147 Factory Service Manual
Year: 2000–2002
Section: Brakes › F12 Brake pedal stiff

‹ Prev F10 Excessive brake pedal stroke Next › G01 Inefficient handbrake

Fault diagnosisF12 Brake pedal stiff

F12 Brake pedal stiff

When the brake pedal is pressed, stiffness is felt during the pedal travel.

Step	Test procedure	Result	Action
0	PRELIMINARY CHECKS Resting your foot on the brake pedal, check that the pedal sinks when the engine is started, because of the vacuum in the braking circuit	OK	Move onto step 1
0		Absence of or partial servo assistance	Move onto step 1
1	CHECK ON VACUUM PIPE Check vacuum pipe: must not be bent or damaged	OK	Move onto step 2
		Pipe bent	Restore the correct geometry End of diagnosis
		Pipe bent	Replace the damaged pipe Op. 3330D26 End of diagnosis
2	CHECK NON-RETURN VALVE Check that the non-return valve is working properly	OK	Move onto step 3
2		Faulty operation	Replace the check valve Op. 3330D26 End of diagnosis
3	CHECKING SERVO BRAKE HYDRAULIC CIRCUIT Check in particular: that there are no air leaks that there is no seizing or sticking	OK	Move onto step 4
		Brake servo with leaks	Replace the brake servo/pump assembly Op. 3330D02 End of diagnosis
		Brake servo with leaks	Replace the brake servo/pump assembly Op. 3330D02 End of diagnosis
4	CHECK ON VACUUM Check the vacuum level in the servo brake system NOTE: Under particular conditions of use, low engine rpm with excessive use of the brakes, the vacuum for operating the servo brake may be insufficient resulting in hardening of the brake pedal. It is pointless to replace the servo unit.	OK	Move onto step 5
		Value incorrect	Eliminate blockages in the manifold End of diagnosis
		Value incorrect	Replace the brake servo/pump assembly Op. 3330D02 End of diagnosis
5	CHECKING PUMP Check that the brake pump has not seized Check that one or more wheels do not remain braked	OK	Move onto step 6
		Seizure of the pump	Replace the brake servo/pump assembly Op. 3330D02 End of diagnosis
		Seizure of a front caliper	Replace the caliper Op. 3310A30 End of diagnosis
		Seizure of a rear caliper	Replace the caliper Op. 3310B36 End of diagnosis
		The car remains braked	Remove the servo/pump assembly Op. 3330D02 and adjust the projection of the pushrod End of diagnosis
		The car remains braked at the rear	Repair the handbrake End of diagnosis
6	CHECK WITH DIAGNOSTIC EQUIPMENT Connect diagnostic equipment (Examiner or other instruments) to the diagnostic socket. Verify: that there are no faults in the ABS control unit that the ABS and EBD warning lights are working	OK	Move onto step 7
		An error is detected in the control unit	Continue following the instructions for the diagnostic equipment End of diagnosis
		Lack of communication with control unit1	Restore the connection between the engine management control unit and the diagnostic connector Wiring diagram E7020 ABS End of diagnosis
7	CHECKING CORRECT OPERATION Test the vehicle before delivery to the customer, to check that the fault is no longer present NOTE: The test is essential, as the braking system involves a safety feature of the car	OK	Incorrect selection of diagnostic procedure
7		Fault persists	Incorrect selection of diagnostic procedure

‹ Prev F10 Excessive brake pedal stroke Next › G01 Inefficient handbrake

Parts & tools for this job For 2000 Alfa Romeo 147

Links open Amazon search results in a new tab. As an Amazon Associate I earn from qualifying purchases.