VARIABLE SPEED FAN CLUTCH Caterpillar

NOTE: A 121-5756 Seal Kit and 121-5767 Overhaul Kit are available for the 6I4427 and 123-6968 Fan Clutches. A 141-9853 Seal Kit and 141-9854 Overhaul Kit are available for the 136-7609 Fan Clutch.

1. Separate the front and back sections by removing bolts (1) and washers (2). Once separated remove the O-ring (3).

2. Separate the hydraulically driven components from the pulley driven fan mounting hub (5) and bearing retainer (7). Clamp the bar of FT2466 Mounting Plate (9) in a vise. Locate the bar in the notches of the clutch body. Bolt FT2467 Rotating Plate (4) to the fan mounting hub (5), using washers (6) to fill the gap. Rotate the fan mounting hub counterclockwise (right hand thread) from the clutch body assembly (8). 408 to 680 N·m (300 to 500 lb ft) torque may be required to break loose the adhesive. Do not completely separate the sections at this time.

3. Turn the unit over to rest the front section on the end cap. Remove clutch body assembly (8), wear plate (10), spring washer (11), facing plates (12), clutch plates (13) and clutch hub assembly (14) from the pulley driven components.

Inspect:

(12) Facing plate.

Groove depth when new:

6I4427 And 123-6968 ... 0.18 mm (.007 in)

136-7609 ... 0.58 mm (.023 in)

They are considered worn out when the groove depth is:

6I4427 And 123-6968 ... 0.06 mm (.002 in)

136-7609 ... 0.19 mm (.007 in)

A. Facing plate thickness when new:

6I4427 And 123-6968 ... 2.54 mm (.100 in)

136-7609 ... 3.38 mm (.133 in)

B. Teeth spacing when new ... 6.35 mm (.250 in)

NOTE: The plate must be flat within 0.13 mm (.005 in).

(13) Clutch plate.

C. Clutch plate thickness when new ... 2.06 mm (.081 in)

NOTE: The plate must be flat within 0.13 mm (.005 in). The surface must be smooth and free of grooves, and must not be discolored by heat.

4. Remove snap ring (15) and backing plate (16) from clutch hub assembly (14).

Inspect:

(16) Backing plate. The backing plate must be flat within 0.13 mm (.005 in).

A. Slot. Must fit on the clutch hub.

(14) Clutch hub assembly. Any wear marks present on teeth must not have straight sides that would restrict plate movement. If wear marks have smooth entry marks, the notches will not restrict plate movement and the clutch hub assembly may be used again.

B. Maximum width (sides must be straight) ... 3.30 mm (.130 in)

C. Minimum thickness ... 16.26 mm (.640 in)

D. Worn area maximum width ... 3.25 mm (.128 in)

5. Disassemble the clutch body assembly. Remove snap ring (17), balance plate (18), large seal ring (19), clutch body (20), dowels (21), piston housing (22) and small seal ring (23).

NOTE: If the dowels are not worn or damaged removal is not necessary.

NOTE: Internal snap rings must not be damaged or worn on the sides. They must be flat and have square edges at the OD.

NOTE: The balance plate (18) must be flat within 0.38 mm (.015 in).

Inspect:

(20) Clutch body.

A. Diameter (maximum) ... 175.79 mm (6.921 in)

B. Diameter (minimum) ... 82.47 mm (3.247 in)

C. Dowel pin hole. Diameter (maximum) ... 8.26 mm (.324 in)

D. Diameter (maximum) with no nicks in the surface ... 58.78 mm (2.314 in)

E. Threads. Make sure the threads are not damaged.

(22) Piston housing.

F. Width (maximum) ... 2.79 mm (.110 in)

G. Diameter (maximum) with out any wear marks in the surface ... 82.60 mm (3.252 in)

H. Dowel pin hole. Diameter (maximum) when new ... 8.92 mm (.351 in)

I. Width (maximum) ... 3.12 mm (.123 in)

J. Diameter (maximum) ... 176.28 mm (6.940 in)

NOTE: Snap rings must fit free in the grooves. The sides must be straight.

NOTE: The dowel pin hole (H) may become elongated do to wear. The maximum diameter across the elongation area must not exceed 10.16 mm (.400 in). Make sure all the adhesive has been removed.

6. Using FT2464 Plate (25), press the fan mounting hub from the front bearing retainer. Remove key (24) retaining these two items.

7. Remove snap ring (26). Drive the seal (27) out with a punch.

NOTE: Internal snap rings must not be damaged or worn on the sides. they must be flat and have square edges at the OD.

8. Use FT2462 Pressing Tube (29) and FT2465 Plate (28) to press bearing (30) from bearing retainer (7).

Inspect:

(7) Bearing retainer.

A. The area must not have any nicks. The surface must seal against the OD of the oil seal. Diameter (maximum) ... 88.938 mm (3.5015 in)

B. The area should not have any nick that rises above the surface.

C. Snap ring. The sides must be straight. The snap ring must fit freely in the groove. Width (maximum) ... 1.19 mm (.047 in)

D. The area must have straight sides and no nicks that rise above the surface. Diameter (maximum) ... 94.988 mm (3.7397 in)

E. Any wear marks present in the slots must not have straight sides that would restrict the plate movement. If wear marks have smooth entry and exit marks, the notches will not restrict the plate movement and the retainer may be used again.

9. Remove the end cap (34) with FT2461 Pressing Tube (31).

Inspect:

(32) And (33) Sleeve bearings. If the bearings appear to be satisfactory then do not remove them, refer to the following illustration. Teflon/Bronze ID surface will appear dark bronze in color when new, and will progress to a light bronze color near the end of its useful life. The illustration visually indicates presence of dark teflon on the light bronze surface.

(34) End cap. The area should not have any nicks that rise above the surface.

A. Diameter (maximum) ... 60.48 mm (2.381 in)

10. If the sleeve bearings need replacement use FT2461 Pressing Bar (31) to remove both bearings (32) and (33) at the same time.

11. Inspect the seal retainer assembly (35). If the seal requires replacement, remove the seal retainer assembly (35) with two small pry bars. If seal is not damaged or worn, omit this step.

12. Care must be taken when removing the wear sleeve (37). With a small chisel, make three indentations or grooves about 120 degrees apart to loosen wear sleeve (37) from the fan mounting hub (36). The surface under the sleeve must not be damaged in any way. If the surface is damaged, it will result in seal leaks after rebuild.

Inspect:

(36) Fan mounting hub.

A. The area must be free of nicks that rise above the surface. Diameter (minimum) ... 63.45 mm (2.498 in)

B. Bearing journal diameter (minimum) ... 60.023 mm (2.3631 in)

C. Bore for sleeve bearing (the surface must be smooth without any steps). Diameter (maximum) ... 42.083 mm (1.6568 in)

D. Key Way. Width (maximum) ... 3.188 mm (.1255 in)

E. Threads. Make sure the threads are not damaged.

F. Bore for the end cap (the surface must be smooth). Diameter (maximum) ... 60.38 mm (2.377 in)

13. Remove hook-type seal rings (37) and snap ring (38).

14. Remove the tube assembly (39) from the shaft.

Inspect:

(39) Tube assembly.

A. The passageway through the tube and ring must be completely open.

B. Diameter (maximum) ... 59.69 mm (2.350 in)

C. Tubes must be tight in the ring. Tubes must not be damaged.

D. Width (minimum) ... 22.949 mm (.9035 in)

E. Orifice. The small orifice must not be plugged.

15. Press out the shaft and bracket assembly from the pulley adapter using FT2461 Pressing Bar (31). Remove the internal snap ring (40). Do not damage the shaft during removal.

NOTE: Internal snap rings must not be damaged or worn on the sides. they must be flat and have square edges at the OD.

16. Inspect the seal retainer (41) for wear or damage. Use a punch to remove seal retainer (41) if necessary.

17. Care must be taken when removing the wear sleeve (42). With a small chisel, make three indentations or grooves about 120 degrees apart to loosen wear sleeve (42) from the shaft. The surface under the sleeve must not be damaged in any way. If the shaft is damaged, it will result in seal leaks after rebuild.

NOTE: Do not separate the shaft from the bracket. Pipe plugs may be removed for cleaning, but they must be replaced using 5P3321 Adhesive.

(43) Shaft and bracket assembly.

A. Diameter (minimum) ... 63.42 mm (2.497 in)

B. Diameter (minimum) ... 60.000 mm (2.3622 in)

C. Diameter (minimum) ... 57.84 mm (2.277 in)

D. There must not be any steps in the surface. Diameter (minimum) ... 38.029 mm (1.4972 in)

E. No steps in the side walls. Seal rings must fit free in the grooves. Width (maximum) ... 2.62 mm (.103 in)

F. Make sure roll pin is not plugged.

G. The groove must have straight sides. The snap ring must fit free in the groove. Width (minimum) ... 3.25 mm (.128 in)

H. Orifice plug may be removed. Install it in the "Oil In" port of the bracket.

NOTE: Some applications do not require an orifice in the oil inlet port, refer to the parts book for your application.

18. With a punch, drive seal (44) out of the pulley adapter.

19. Using FT2462 Pressing Tube (29) and FT2465 Plate (28) press out rear bearing (45).

20. If the pulley must be removed from the pulley adapter (46), mark the two items so they can be assembled back in the same position to maintain balance.

Inspect:

(46) Pulley adapter.

A. Pulley. The pulley must not be damaged and no excessive wear on the sides of the grooves.

B. Threads. The threads must not be damaged.

C. There must not be any nicks above the surface.

D. Diameter (maximum) ... 109.987 mm (4.3302 in)

E. The sides must be straight. The snap ring must fit freely in the groove. Width (maximum) ... 2.82 mm (.111 in)

F. Must have straight wall and not oval.

G. Diameter (maximum) ... 88.938 mm (3.5015 in)