Measure And Set Preload Of Taper Roller Bearings Of Differential - AR27.50-P-0570-03MFA

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Transmission 724.1 in model 118, 177, 247

MODIFICATION NOTES

11.12.2019

Document completely revised

Fig 1: Identifying Parallel Support (168 589 03 21 00)

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Fig 2: Identifying Support Fixture (724 589 05 31 00)

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REPAIR MATERIALS

Number	Designation	Order number
BR00.45-Z-1038-04A	Loctite 7200	A 010 989 90 71
BR00.45-Z-1046-04A	Loctite 7063 (400 ml) cleaning spray	A 001 986 71 71 09

Required special tools:

2x parallel gauge (168 589 03 21 00) (05)

The following tools are required from the support fixture (724 589 05 31 00):

Mount (01) 724 589 05 31 01
Thrust device (02) 724 589 05 31 02
Measuring plate (03) 724 589 05 31 03

Commercially available devices/tools

Digital depth gauge

Make ready for measurement

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A digital depth gauge (04) is required in order to determine the differential spacer ring (52E).

Thoroughly clean contact surfaces on tapered roller bearings (44a, 44b), on clutch housing (27K) and on transmission housing (27G).
Check for absolute cleanliness. Measurement errors occur otherwise. These will result in damage to the transmission.

Do not use any sharp-edged tools or abrasive paper. Otherwise, the face and contact surfaces will be damaged.
Insert the new tapered roller bearing outer race (52L) of the transmission housing (27G) into the bottom of the mount (01).
Position the new tapered roller bearing outer race (52L) of the clutch housing (27K) on the tapered roller bearing (44a).
Place measuring plate (03) on tapered roller bearing outer race (52L) of clutch housing (27K).
Insert differential (1) with tapered roller bearing outer race (52L) of clutch housing (27K) and measuring plate (03) into mount (01).
Load differential (1) with 300 Nm by turning thrust device (02).
Observe marking on pressure device (02).
In readiness for measurement, turn differential (1) several times.

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Determine values (A, B, C) of differential (1)
Place digital depth gauge (04) onto upper surface of mount (01), measure to upper surface of mount (01) and then "zero" digital depth gauge (04).
This sets the digital depth gauge (04) to the "zero position".
Using digital depth gauge (04), measure through hole (3) and hole (4) in mount (01) to measuring plate (03) and note down values (B1 and B2).
The value (A) is derived from the height of the mount (01) (236 mm); this is required for further calculation.

Calculate the mean value (B) from the two measured values (B1 and B2); the mean value is required for further calculation.

The value (C) is derived from the height of the measuring plate (03) (25 mm); this is required for further calculation.

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Determine value (D) of Transmission housing (27G)
Place parallel gauges (05) onto transmission housing (27G).
Place digital depth gauge (04) onto parallel gauges (05), measure to sealing surface of transmission housing (27G) and then set digital depth gauge (04) to zero.
This deducts the height of the parallel gauges (05) for the value (D).
Using digital depth gauge (04), measure from parallel gauges (05) up to lower edge of bearing seat (5) at three points and note down values (D1, D2 and D3).
Calculate the mean value (D) from the measured values (D1, D2 and D3); the mean value is then required for further calculation.

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Determine value (E) of clutch housing (27K)
Place parallel gauges (05) onto clutch housing (27K).
Place digital depth gauge (04) onto parallel gauges (05), measure to sealing surface of clutch housing (27K) and then set digital depth gauge (04) to zero.
This deducts the height of the parallel gauges (05) for the value (E).
Using digital depth gauge (04), measure from parallel gauges (05) up to lower edge of bearing seat (6) at three points and note down values (E1, E2 and E3).
Calculate the mean value (E) from the measured values (E1, E2 and E3); the mean value is then required for further calculation.

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Calculate thickness (S) of differential spacer ring (52E) for preload of tapered roller bearings (44a, 44b):

Calculation of spacer ring thickness (S):

S (thickness of differential spacer ring (52E)) = ((D+E) - (A - (B + C))) + 0.1 mm (nominal load influence)

Example calculation:

S = ((105.50 mm (D) + 39.95 mm (E)) - (236 mm (A) - (66.55 mm (B) + 25 mm (C)))) + 0.1 mm (nominal load influence) ←

S = ((145.50 mm (D + E)) - (236 mm (A) - (91.55 mm (B + C)) + 0.1 mm (nominal load influence) ←

S = ((145.50 mm (D + E)) - (144.45 mm (A - (B + C)) + 0.1 mm (nominal load influence) ←

S = 1.05 mm ((D+E) - (A - (B + C))) + 0.1 mm (nominal load influence) ←

S=1.15 mm

The differential spacer ring (52E) is available in thicknesses from 1.10 mm to 1.75 mm in increments of 0.05 mm (round the calculated value up/down to 0.05 mm). In the above calculation example, a differential spacer ring (52E) with a thickness of 1.15 mm is installed.