Iveco Stralis AT/AD. Manual

85809

78334

78336

Figure 28

Figure 29

Figure 30

Take the front half-casing (1), complete with the rotor, to a
press. Position the half casing on the supports (2) and (3) and
withdraw the rotor shaft (3) from the inner race (4) of the
taper roller bearing and remove the latter from the
half-casing (1).

For all types of retarder, proceed as follows.

43986

Figure 31

Using a punch (1), extract the external race (2) of the bearing
from the stator (3).

78335

Figure 32

70975

Using a punch, extract the external ring (2) of the bearing
from the front half box (1).

Figure 33

Using the yoke (1), rods (2) and block (3), withdraw the
stator (4) from the rotor (5) and from the half casing (6).

Withdraw the pins (1) and remove the half rings (2).

Remove the plug (1) and withdraw from the half casing (6):
the spring (2), the pistons (3 and 4) and the spring (5).

INTARDER - ZF HYDRAULIC RETARDER

TRALIS

AT/AD

Base - January 2003

Carefully clean the single parts comprising the
retarder and check their state of wear for them to be
reused.
Clean the threads of the plugs and their seats of
remains of sealant.
Check the mating surfaces are not deformed and
moisten the sliding surfaces.
Replace all the sealing and safety elements and the
valve springs with new parts.

78337

1. Screw - 2. Washer - 3. Gear - 4. Tapered roller bearing - 5. Stator - 6. Seal - 7. Split ring - 8. Rotor - 9. Split ring -

10. Front box - 11. Seal - 12. Safety cover - 13. Half rings - 14. Tapered roller bearing - 15. Valve - 16. Spring -

17. Washer - 18. Plug - 19. Plug - 20. Washer

A = Components of the friction reducing valve: (if present)

21. Pins - 22. Half rings - 23. Spring - 24. Piston - 25. Piston - 26. Spring - 27. Washer - 28. Plug.

Figure 34

Checking the component parts of the hydraulic
retarder

INTARDER - ZF HYDRAULIC RETARDER

TRALIS

AT/AD

70974

43983

43985

Figure 35

Figure 36

Figure 37

Heat the hole of the stator (4) to approximately 80ºC. Using
the keying device 99374093 (2) and grip 99370007 (1),
mount the external race (3) of the tapered roller bearing.

Fit the new split rings (2 and 3) on the shaft (1) of the rotor.

Heat the gear (3) to approximately 85ºC and fit it on the shaft
of the rotor (4). Fit the washer (2) and provisionally tighten
the check screw. After cooling, lock the check screw to the
required torque with a torque wrench (1). Fit a new seal (5)
on the stator (4).

Figure 38

43984

Lock the rotor (3) in the vice as shown in the figure. Mount
the stator (2).
Heat the internal ring of the bearing (1) to approximately
100ºC and mount it in its seat.

70975

Fit the rotor shaft centring plate 99370048 (3) to the front
half box (2). Heat the half box (2) to 90

÷ 100ºC and position

the rotor and stator assembly (1) on the half box (2) as
shown in the figure.

Figure 39

Fitting the hydraulic retarder

For hydraulic retarders without friction reducing valves
only.

Figure 40

70979

Using a press, drive the rotor and stator assembly (1) down
to the stop in the front half box (4) so that the arrows (3 and
4) are aligned. A misalignment of 1 mm is permissible. Keep
the assembly (2) under the action of the press for 5 minutes
to ensure it gets bedded.
Remove the centring plate (3, Figure 39).

INTARDER - ZF HYDRAULIC RETARDER

TRALIS

AT/AD

Base - January 2003

For hydraulic retarders with friction reducing valves, proceed
as follows.

78342

Figure 41

Figure 42

Figure 43

78340

Install in the half casing (6) the spring (5), the pistons (3 and
4) and the spring (2); fit a new gasket to the plug (1) and
tighten to a torque of 50 Nm.

78343

Figure 44

78339

Attach the rotor shaft locating plate 99370048 (3) to the
front half-casing (2). Position the rotor assembly (1)
complete with circlips in the half casing (2).

78341

Position the half rings (2) in the half casing (4) so that the
projecting parts engage the grooves in the pistons (1) and fix
them to the half casing with the pins (3).

Figure 45

Heat the gear (3) to approx. 85

°C and fit it on the rotor shaft.

Fit the washer (2) and provisionally tighten the retaining bolt
(1). Once the gear (3) has cooled, tighten the retaining bolt
to the prescribed torque.

Position the assembled half casing (2) in the press. Heat the
seating of the stator (1) to 80

°C. Fit the stator (1) with a new

oil seal in the front half casing (2), making sure that the arrows
(3 and 4) are aligned. An alignment error of up to 1 mm is
permissible. Keep the stator (2) under the press for 5 minutes
to ensure it is fully bedded down.
Remove the locating plate (3, Figure 41).

INTARDER - ZF HYDRAULIC RETARDER

TRALIS

AT/AD

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Iveco Stralis AT/AD. Manual - part 133