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Iveco Daily. Manual - part 326

HYDRO-PNEUMATIC SYSTEM - BRAKES

AILY

Base - May 2004

CHECKS

Device

Designation

Checks

Pressure Reducer

Connect a vacuum meter to the intake line.
At full operation the pressure reduction must reach the value
of 0.80

÷ 0.85 bar. If this value is not obtained, check if there

are any leaks in the pressure piping and servo brake
components.
Check that the distance between the top of the rotor and
cover (with unit fitted) is comprised in the range 0.07

0.14mm.

Vacuum servo brake

Check the functionality and that there are no leaks. With the
vacuum meter fitted on the piping between the pressure
reducer and servo brake with engine at full speed, check that
the pressure reduction values are in the range 0.80

÷ 0.85 bar

with the pedal both released and pressed fully down for a
period of 1 minute of rotation of the engine.

Brake liquid compensation tank

Check the level of the brake liquid and eventually top up with
Tutela DOT SPECIAL to the specified level. Change the brake
liquid once per year.

Load proportioning valve

Check that the values measured with special manometers, via
the test points, correspond to those indicated on the
self-adhesive plate applied to the inside of the vehicle.

Disk brake caliper

Check the condition of the brake linings; check for scratches
on the discs and the efficiency of the pistons.

Pipes and fittings

Ensure that metal pipes are in perfect condition, with no dents
or cracks. Also make sure that they are not near sharp edges
of the body work or chassis that could damage them.
Check that the rubber and cloth flexible hoses are not in
contact with oil or mineral grease, or rubber solvents. Press
hard on the brake pedal and check that the pipes are not
blown, and check that there are no leaks.
Check that all brackets fastening the pipes are securely fixed
- loose fastenings cause vibrations that could give rise to
breakage.
Check that there are no leaks from fittings, otherwise tighten
them fully, taking care when tightening not to cause irregular
pipe torsion.
In all the above cases the parts are to be replaced if there is a
minimum of doubt as to their efficiency.
Apart from their condition, it is recommended to replace hoses
after considerable mileage, or after a period of long vehicle use.
This will avoid sudden breakage due to age and fatigue.

Functional check of vacuum brake system

With the engine stopped, press the brake pedal a few times in order to annul the vacuum in the servo brake. Press the pedal once
again and keep it pressed, in the brake position, by putting a certain pressure on it. Start the engine and check the pedal stroke:

- if the stroke of the pedal increases, this implies that the servo brake and pipes are satisfactory;

- if the pedal remains still, this implies that the outside has penetrated into the vacuum plant that is not perfectly sealed, or the

servo brake is faulty.

Revi - February 2005

HYDRO-PNEUMATIC SYSTEM - BRAKES

AILY

POSSIBLE CAUSES

CURE

Oil leakage from cover

Incorrect

driving

torque

between power reducer and
engine.

Lock screws to correct driving torque indicated in appropriate
table.

Cover

seal

surface

not

completely flat.

Check the seal surfaces, replace any defective parts or place
them on a flat surface.

Broken seal between pump
and engine.

Replace seal.

Poor efficiency

Excessive backlash between
the blades and sliding surfaces.

Replace blades, or the entire pressure reducer.

Bad sealing of connecting pipes
or uni-directional valve.

Check the seal and eventually replace the connecting pipes or
replace the uni-directional valve.

Insufficient lubrication.

Carefully clean the oil pipes.

This is the component which generates a reduction in
pressure for operation of the servo brake.

BRAKING SYSTEM MAIN COMPONENTS

32277

32279

Figure 30

Figure 31

This is a device which increases the force applied by the pedal
and consists of two main components:

- a power reducer pneumatic section;

- an hydraulic section (master cylinder and brake liquid

tank).

The servo brake is manufactured in such a way that in case
the pneumatic section fails, the brakes can still work. In this
case the braking action is obtained by one master cylinder.

790530

Vacuum pump

Diagnostics

794101

Vacuum servo brake

The figure shows the version for vehicles with engine 8140.
As regards the vehicles with engine F1A/F1C, the vacuum de-
vice is incorporated into the vacuum oil pump unit.

Revi - February 2005

One end of a transparent plastic pipe (2) should be fitted to
the bleeder screw (1) with the end placed into a container
(3) that has been partially filled with brake liquid.

Repeatedly press the brake pedal

By maintaining the brake pedal in the down position unscrew
the bleeder screw (1) one full turn.

Tighten the bleeder screw, repeatedly press the brake pedal.

Repeat the above operation until the brake liquid comes out
in a uniform manner.

Bleed off the air from the opposite brake assembly. Check
that the level of brake liquid in the relevant tank is always
sufficient.

This operation will allow the air in the hydraulic circuit liquid
piping to be expelled.

45022

45021

52399

Figure 32

Figure 33

Figure 34

Front brake circuit

Disconnect the load proportioning valve control rod and
lock it at the top so as to set the proportioning valve in the
fully open position.

Bleed off the air from the hydraulic circuit as described for the
front brake circuit.

784010

Bleeding air from the hydraulic cir-
cuit with deaerator device (vehicles
not equipped with ABS)

Front brake circuit

Rear brake circuit

Having terminated this operation connect the load
proportioning valve control rod.

Finish bleeding-off air from the brake circuit, top up
to the maximum level with Tutela DOT SPECIAL
brake liquid.

784010

Bleeding air from the hydraulic cir-
cuit (vehicles not equipped with
ABS)

As an alternative you can bleed-off air from the brake circuit
with the deaerator device 99306010 by following the
procedures below:

1. load the air tank (4);

2. fill the tank with brake liquid (5);

3. one end of a transparent plastic pipe (6) should be fitted

to the bleeder screw with the end placed into a container
that has been partially filled with brake liquid;

4. replace the brake liquid tank cover with one (7) taken

from the box supplied with the deaerator;

5. insert the deaerator 99306010 pipe (1) on the cover of

the brake liquid tank;

6. unscrew the bleeder screw one full turn, open the cock

valve (3) until there is a reading of 1

÷ 1.2 bar on the

manometer (2).

When the brake liquid comes out in a uniform manner from
the circuit, close the bleeder screw and discharge air from the
aerator tank (4). Repeat this operation for all wheels.

HYDRO-PNEUMATIC SYSTEM - BRAKES

AILY

Base - May 2004

NOTE

After air bleeding from the braking circuit has been completed, fill with brake fluid up to the top level (do not fill with
oil that has already been used).

NOTE

The procedure must be performed with the engine stopped and the key turned to running (Key ON).
Get connected to the diagnosis take-off located in the cabin, on the passenger’s side, by means of a suitable instrument. Follow
the “BLEEDING” procedure described by the instrument.

Press the brake pedal over and over again during the process.
The correct blow-off sequence for the four wheels is as follows:
- rear left wheel (RL)
- front left wheel (FL)
- front right wheel (FR)
- rear right wheel (RR)
As regards the systems of the ABS 8/ESP 8 type, no other sequence is permitted. As far as ABS 5.3 systems are
concerned, on the contrary, you may act on the single wheels without having to perform the entire procedure.

After every single wheel has been bled, visually inspect the brake fluid level and top up, if necessary. Do not fill with
fluid that has already been used.

In the event that either one single phase or the entire blow-off process is repeated, you will have to wait at least 5
minutes in order to let the system solenoid valve cool. Otherwise, the valves themselves may be damaged due to
overheating.
Prior to tightening the drain screws, make sure that the corresponding routine has been completed, and the brake
fluid flows out smoothly (no air bubbles should appear).

ABS 5.3 system bleeding procedure sequence

In order to ensure correct bleeding, the vehicle is to be set in a proper way. You will have to clean the drain screws and procure
a transparent tube and a container partially filled with brake fluid, to be connected to the screw of the wheel being bled.

Air bleeding from the ABS/ESP system hydraulic circuit

Call the “BLEEDING”

routine

on any of the four wheels

Open the drain screw of the

corresponding wheel.

When bleeding has been

completed (as signalled by the

diagnosis instrument), close the

screw and proceed with the next

wheel if other wheels need

bleeding.

In case of operation failure,

repeat the procedure.

HYDRO-PNEUMATIC SYSTEM - BRAKES

48/1

AILY

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