DRESSTA TD-25M EXTRA, Service Manual

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STEERING DRIVE
SECTION 7E
Page 17
DRESSTA TD-25M EXTRA
STEERING DRIVE
b). Remove retaining ring (72) and thrust race (73) that were previously installed. Measure the
D distance as shown in Fig. 7E.20B. Take the measurement in four 90 [
°
] spaced places.
Select a thrust race (73) and one of five retaining rings (72) in a way that their total thickness
shall equal to D dimension.
Check the pinion gear shaft (79) rolling torque with a 1.249.0017 tool equipped with
a 1.264.0024 socket. If the rolling torque ranges between 0.5 to 2 [Nm] do not use a new
retaining ring (72), the assembly is ready.
If the rolling torque ranges between 2 to 3 [Nm], install a retaining ring (72) that has
0.05 [mm] less in thickness that the ring that was used for measurements.
If the rolling torque ranges between 3 to 6 [Nm], install a retaining ring (72) that has
0.05 to 0.1 [mm] less in thickness that the ring that was used for measurements.
All retaining rings (72) are within maximum tolerance range equal to
±
0.05 [mm] and make
possible to get the correct thickness.
Following are examples of thrust race (73) and retaining ring (72) selection and installation:
For D dimension equal to 6.4 [mm] and a torque equal to 1.5 [Nm] install a 3.18 [mm] thrust
race (73) and a 3.22 [mm] retaining ring (72) to get a total thickness equal to 6.4 [mm].
In that case nothing is to be added to a 6.4 [mm] dimension.
For D dimension equal to 6.2 [mm] and a torque equal to 0.5 [Nm] install a 3.18 [mm] thrust
race (73) and a 3.05 [mm] retaining ring (72) to get a total thickness equal to 6.23 [mm]. In
that case 0.03 [mm] was added.
For D dimension equal to 6.3 [mm] and a torque equal to 4.5 [Nm] install a 3.18 [mm] thrust
race (73) and a 3.05 [mm] retaining ring (72) to get a total thickness equal to 6.23 [mm]. In
that case 0.07 [mm] was removed.
c). Apply a force of 25000 [N] to a cone bearing inner ring (75) to get a 0.13 [mm] bearing shift
towards the assy inner side to facilitate selected retaining ring (72) and thrust race (73)
installation. Make use of a 2.5 [T] hydraulic press to get a required force.
d). Place the pinion gear shaft (79) on pinion gear housing (76) and tap pinion gear shaft end
(79) with a 1 [kg] brass hammer to ensure a positive contact of thrust race (73) and retaining
ring (72) installed before a final pinion gear shaft (79) rolling torque measurement. Make use
of a 1.249.0017 tool equipped with a 1.264.0024 socket to measure the rolling torque that for
new bearings should be equal to 1.5
±
1.5 [Nm].
NOTE: If you install bearings that were used previously, adjust the rolling torque to get a reading
ranging from 0 to 1.5 [Nm].
e). Some cases need a thrust race (73) and retaining ring (72) total thickness in excess
of 6.4 [mm]. If this is a case add spacer (74) to thrust race (73) and select a correct retaining
ring (72) in such a way that their total thickness makes possible to get the correct rolling
torque.
Following are examples that make use of spacer (74) necessary:
For D distance equal to 6.5 [mm] and rolling torque of 2.8 [Nm] place a 0.38 [mm] spacer
(74), a 3.12 [mm] thrust race (73) and 2.95 [mm] retaining ring (72). That results in total
thickness eqal to 6.45 [mm]. In that case 0.05 [mm] was removed.
For D distance equal to 6.7 [mm] and rolling torque of 5.6 [Nm] place a 0.38 [mm] spacer
(74), a 3.12 [mm] thrust race (73) and a 3.1 [mm] retaining ring (72). That results in total
thickness eqal to 6.6 [mm]. In that case 0.1 [mm] was removed.
NOTE: Due to thrust race (73) and retaining ring (72) thickness tolerance pay a particular attention
while selecting these elements to account for their actual thickness.