Porsche 928 B2 Piston

19.Engage brake band B 1 in assembly lock (arrowed).

20.Insert clutch K 1 while turning until teeth engage.

21.Insert brake band such that pin is facing from assembly lock to pressure unit B 1 (see Step 19).

22.Do not insert axial bearing and shims until axial play of clutch K 1 has been measured.

23.Push pressure pin into pressure unit B 1 (replace 0-rings).

25.Insert brake-band guide. The locating pins must engage the holes in the case.

Porsche 928 Gearbox

24.Insert pressure unit, screw in threaded plug or transmission protection switch in '87 models onward and tighten. Tightening torque 70 Nm (52 ftlb).

26.Check axial play "B" for clutch K 1 and correct.

1 = Axial bearing

2 = Rotation washer

B = Axial play

Measure distance "a":

Place seal on front cover. Place Special Tool 9313 on flange and with depth gage, measure to seal, (e.g. 119.0 mm).

Measure distance "b":

Place measuring bridge 9113 on prepared face and, with depth gage, measure to clutch K 1 (e.g. 123.6 mm)

A = Spacer (discontinued as of transmission No. 472 213)

The difference between the two measurements is the axial play "B" (without axial bearing, rotation washer or shim).


"b" = 123.6 mm "a" = - 119.0 mm

3.8 mm Play without axial


Correct play to 0.8 mm by installing axial bearing, rotation washer and the appropriate shims.

Select axial bearing, rotation washer and shims such that the overall thickness is 3.8 mm.

Insert these spacers as calculated (thickness in example, 3.8 mm)

28.With a blob of grease, attach spacer to support and place front cover with seal in position. Tighten mounting bolts. Tightening torque: 13 Nm (10 ftlb).

Sch Moteur
A - Centering pins 9321

29.Turn assembly support so that output shaft is facing upward.

1 = Axial bearing

2 = Rotation washer

27.Check that teflon rings in front cover and on input shaft are correctly seated.

Circlip Injector Tool For 996

30.Insert circlip and position spacer right way round.


The spacer has been in use since approx. December, 1986.

31.Install helical gear and axial holder.

32.Insert 0-ring and install centrifugal-force controller

33.Swing axial holder over to centrifugal-force controller so that holder engages groove of controller shaft.

34.Insert cover and install circlip. Then pull cover out so that it makes contact with circlip around entire circumference.

36.Place secondary pump in position and tighten hex bolts. Tightening torque: 8 Nm (5.9 ftlb).

35.Install backer and insert 0-ring.

37.Recheck seating of axial holder and tighten new nut. Tightening torque: 6 Nm (4.4 ftlb).

38.Insert oil tube (arrowed) and tighten socket-head bolt. Tightening torque: 8 Nm (5.9 ftlb).

The oil tube is discontinued as of '87 models.

40.Push roller onto sprung linkage, place plastic guide in position and push into positioning holes.

Circlip Bore And Shaft GuideFix Porsche

39.Insert detente plate with shaft, screw in socket-head bolt and tighten. Tightening torque: 8 Nm (5.9 ftlb). Push sprung linkage onto detente plate and install circlip (arrowed). The circlip is discontinued as of '87 models. Linkage is staked to detente plate.

41.Place correct number of shims on helical gear.

Measure distance "a":

42.Install parking lock pawl, expander spring and parking lock gear.

Calculate thickness of shims for bearing assembly:

7 = Taper roller bearing - inner race

9 = Shim for bearing assembly

10 = Shim for axial play "CM

11 - Rotation ring C = Axial play

Use a depth gage to measure from bearing surface of taper roller bearing to bearing face of bearing assembly {e.g 34.55 mm). However, because the specified distance may not exceed 34 ± 0.05 mm, 0.55 mm must be made up in shims.

43.Measure axial play "C" of output shaft (clutch K 2) and correct.

Use a depth gage to measure from rotation ring to seal (e.g. 15.3 mm).

A = Special Tool 9312 B = Rotation ring C = Seal

Measure distance "a":

Measure distance "b":

Push Special Tool 9312 onto output shaft and tighten collar nut. Tightening torque 380 Nm (280 ftlb). To do so, engage parking lock pawl.

Place seal in position.

Porsche 928 Clutch Design


34.55 mm As-is (measured on bearing assembly) - 34.00 mm Specified (design distance)

0.55 mm Thickness of shims

Install bearing assembly with shims as calculated in case and tighten all mounting bolts. Tightening torque: 33 Nm (24 ftlb).

Use a depth gage to measure from case bearing face to inner race of cylindrical roller bearing (e.g 15.9 mm).

Distance "b" minus distance "a" equals distance "C".


Distance "a" 15.9 mm Distance "b" - 15.3 mm

Distance "C" 0.6 mm

Correct axial play "C" to 0.4 + 0.1 mm by inserting or removing shims beneath parking lock gear.


Remove bearing assembly from case and do not reinstall finally until case is fully assembled (see page 37 - 131).

47.Install vacuum-control unit with holder and tighten socket-head bolts. Tightening torque: 8 Nm {5.9 ftlb). Place starter interlock switch in position and slightly tighten mounting bolts (do not tighten fully). Place range selector lever in position such that carrier is fixed in lever. Insert hex bolt and tighten.

Tightening torque: 8 Nm (5.9 ftlb).

Porsche 924 Front Axle Torque

44.Insert injector tube.

Discontinued as of '87 models,

45.Screw in kickdown solenoid valve and tighten. Tightening torque: 20 Nm {15 ftlb).

46.Insert modulating pressure control valve and pressure pin.

48.Insert sealing ring with lip in brake band piston B 1 such that sealing lip is pointing in the direction arrowed.


Brake-band pistons with five different pressure pins marked with grooves (arrowed) are available to correct play at brake band B 1. The brake band piston with the shortest pressure pin has no identification groove, the brake band piston with the longest pressure pin has four identification grooves.

Brake band pistons with removable pressure pins were installed as of transmission No. 788 606. To correct play, use shims available in three thicknesses 0.5 mm, 1.0 mm and 1.5 mm.

Vial Debajo Linea Electrica Aerea

1 = Brake band piston B 1

2 = Pressure pin

3 = Sealing ring with lip

49.Bolt Special Tool 9316 to transmission case and insert brake band piston B 1 with compression springs and Special Tool 9320. Screw spindle down while ensuring that piston pressure pin enters brake band (do not damage sealing ring with lip).

Kaeser Sigma Profile


Play is set with either a flat or pointed adjuster screw for Special Tool 9320, depending on the design of brake band piston.

Piston with rivetted pressure pin = hex screw with point

Piston with removable pressure pin = flat hex screw M 10 x 1

50.Insert circlip, relieve Special Tool 9316 and remove.

51.Measure and adjust play "L" of brake band.


The thread of Special Tool 9320 has a 1 mm lead, which means that one full turn equals 1 mm travel.

Turn screw of Special Tool by hand until resistance is felt.

54.Install pressure pin with larger diameter toward brake band B 2.

55.Insert teflon ring with grease in groove and insert pressure pin.

Travel at brake band must be

(2.3 ftlb) torque must be reached after 3...4 turns.

52.If travel is excessive, fit a brake band piston with a longer pressure pin; if travel is too short, fit a brake band piston with shorter pressure pin. As of transmission No. 788 606, use appropriate shims to correct travel.

Tighten screw further with torque wrench, counting turns and tightening to 5 Nm (2.3 ftlb).

53.Place Special Tool 9316 in position and bolt down. Remove brake band piston B 1 and install brake band piston cover instead of Special Tool 9320.


Pressure pins are available in 4 lengths for correcting travel at brake band B 2.

56.Insert brake band piston B 2, ensuring that pressure pin engages brake band.

57.Press in brake band piston cover B 2 and insert circlip.

58.Measure play "L" at brake band B 2 and adjust: press brake band B 2 toward brake band piston at support lug (as arrowed) so that brake band piston contacts brake band piston cover. Use a feeler gage to measure distance "a" at brake band.

Brake Band Support

Again, press brake band B 2 toward pressure unit at support lug (as arrowed) and measure distance "a" again.

The Word Love Photography

59.Insert one-way valve and filler.

The difference between the two measurements is the play "L". Adjust play "L" to 6...7 mm by changing pressure pin in brake band piston B2.

59.Insert one-way valve and filler.

60.Insert brake band guide.

61.Insert temperature throttle and push into oil duct until throttle is flush with casing. Insert oil wiper.

62.Install lower cover with back plate, in so doing, insert oil tube in casing bore.

63.Insert combination bolts and tighten nuts slightly (do not tighten fully).

64.Engage return spring.

65.Place leaf spring with holder in position and tighten mounting bolts slightly (do not tighten fully).

Blower Tattoo

Note: 67.Insert combination bolts and tighten to 8 Nm {5.9 ftlb).

Holder must be properly pinned in place.


Note length of bolts. The three arrowed bolts are only 50 mm long, the remaining 12 bolts are 55 mm long.

Begin by tightening the two bolts A/B slightly to center the shift valve casing.

68.Tighten combination bolts for back plate and leaf spring holder to 8 Nm (5.9 ftlb)

66.Install shift valve casing, range selector must engage carrier on detente plate (arrowed).

Porsche 928 Oil Pan Gasket

70.Place ATF filter in position, insert cross-recess head screws and tighten to 4 Nm (2.95 ftlb).

69.Check clearance "a" between locking piston and stop on sprung linkage, adjust if necessary. Use plastic clips to adjust play to 0.4...1.0 mm with selector in "N" position. Plastic clips are available in three thicknesses.

71.Install oil pan with gasket, screw down mounting bolts and tighten to 8 Nm (5.9 ftlb).

72.Set range selector to "N" position, insert a holding pin made of 4 mm welding wire {or 4 mm twist drill) through selector into hole in shift valve casing and tighten mounting bolts to 8 Nm {5.9 ftlb). Remove holding pin.


Once the transmission has been installed, check settings of cables for selector lever and control pressure and check modulating pressure, reset if necessary.

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