engine BMW 525i 1998 E39 Workshop Manual

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Driveshaft
Driveshaft problems and causes
Symptom Probable cause Corrective action
Vibration when starting off Center bearing rubber deteriorated. Inspect center bearing and rubber. Replace if necessary.
(forward or reverse)
Flex-disc damaged or worn.
Inspect flex-disc. Replace
if necessary.
Engine or transmission mounts
faulty. Inspect engine and transmission mounts. Align or
replace, if necessary.
Front centering guide worn, or driveshaft
Checic front centering guide and replace
if necessary.
mounting flanges out of round.
Check
runout of driveshaft flanges.
Universal joint worn or seized.
Check universal joint play and movement. Replace
driveshaft if necessary.
Driveshaft misaligned. Check driveshaft alignment.
Noise during onloff throttle Final
drive components worn or damaged
Remove final drive and repair. 331 Final Drive
or when engaging clutch. (excessive pinion-to-ring-gear clearance).
Drive axle or CV joint faulty.
Inspect drive axles and CV joints. Repair or replace as
necessary.
331 Final Drive
Vibration at 25 to
30 mph
Front centering guide worn, or driveshaft
Check front centering guide and replace if necessary.
(40 to 50
kmlh). mounting flanges out of round or damaged.
Check runout of driveshaft mounting flanges.
Universal joint worn or seized.
Check universal joint play and movement. Replace
driveshaft if necessary.
Flex-disc damaged or worn.
Inspect flex-disc. Replace if necessary.
Center bearing rubber deteriorated.
Inspect center bearing. Replace if necessary.
Misaligned installed position. Check driveshaft alignment.
Vibration, audible rumble Front centering guide worn, or driveshaft
Check front centering guide and replace
if necessary.
over
35 mph (60 kmlh). mounting flanges out of rouncl or damaged.
Check runout of driveshaft mounting flanges. - -
Mounting flange bolts loose or holes worn.
Remove driveshaft and check transmission output flange
and final drive input flange. Replace if necessary.
Driveshaft unbalanced. Check driveshaft for loose or missing balance weights.
Have driveshaft rebalanced or replace if necessary.
Universal ioint worn or seized.
Check universal ioint
~lav and movement. Reolace ' .. driveshaft if necessary.
Center bearing faulty.
Replace center bearing.
.
Final drive rubber mount faulty.
Inspect final drive rubber mount and repiace if necessary.
Driveshaft misaligned.
Check driveshaft alignment.

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Driveshaft
Repair kits for the universal joint are not available for BMW
driveshafts.
A worn or damaged universal joint usually require
replacement of the driveshaft.
The driveshaft is balanced to close tolerances. Whenever it is
to be removed or disassembled, the mounting flanges and
driveshaft sections should be marked with paint or a punch
before proceeding with work. This will ensure that the
drive-
shaft can be reassembled and installed in exactly the original
orientation.
1. Rear section of drive shaft
2. Hex bolt, MI2 x 1.5 x 25
3. Knurled bolt
4. Clamp
5. Reinforcement
6. Seal
7. Constant velocity joint
8. Circlip
9. Hex nut
10. Hex bolt, M12x 1.5~58
11. Centering sleeve
12. Flexible disk
13. Self-locking hex nut
14. Front section of driveshaft
15. Center bearing
16. Dust cover (some models)
17. Spacer (some models) -

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Driveshaft, aligning
The alignment of the driveshaft does not normally need to be
checked unless the engineltransmission or the final drive
have been removed and installed. if ail other parts of the
driveshaft have been inspected and found to be okay, but
there is still noise or vibration, driveshaft alignment should be
checked.
There are two important driveshaft alignment checks. The
first is to make sure that the driveshaft runs straight from the
transmission to the final drive, without any variation from
side-
to-side caused by misalignment of the engineltransmission in
its mounts. Make a basic check by sighting along the
drive-
shaft from back to front. Any misalignment should be appar-
ent from the center bearing forward.
To adjust the side-to-side alignment, loosen transmission or
engine mounts to reposition them, then retighten mounts.
The driveshaft should be exactly centered in driveshaft tun-
nel.
The second important driveshaft alignment check is more
complicated. It checlts the amount the driveshaft is angled
vertically at the joints. This angle is
lknown as driveshaft
deflection.
In general, there should be little deflection in the driveshaft
between the engine, the center bearing, and the final drive.
Precise checks require the use of a large protractor or some
other means of measuring the angle of the engine and the fi-
nal drive and comparing these angles to the angle of the
. . driveshaft sections.
- To change the deflection angle, shims can be placed be-
tween the center bearing and the body or between the trans-
mission and its rear support. When using shims to change a
deflection angle, keep in mind that the angle of adjacent
joints will also change. Deflection angles should be as small
as
oossible.

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-.- .
/ Driveshaft Driveshaft, removing
CAUTION-
. Be sure the wheels are off the ground before removing the
driveshak Set the parl(ing brake before removing the
driveshaft.
Once the driveshaft has been removed, the vehicle can
roll regardless of whether the transmission is in gear or
not.
The driveshaft is mounted to the transmission and final
drive
with self-locliing nuts. These nuts are designed to
be used only once and should be replaced during reas-
sembly.
Remove complete exhaust system. See
180 Exhaust
System.
- Remove exhaust heat shields.
- Support transmission with transmission jack.
< Loosen transmission mount nuts (arrows) on real
transmission support crossmember.
- Release wiring harness retainers from rear transmission
support crossmember.
< Remove mounting bolts (arrows) for rear transmission sup-
port crossmember. Slide crossmember rearward to remove.
- Matchmark front and rear driveshaft halves to corresponding
transmission output and final drive input flanges.
4 Remove nuts securing driveshaft mounting bolts at transmis-
sion output flange. Counterhold bolts (arrows) at transmis-
sion flex-disc. Discard old nuts.
- Hang driveshaft front section from body using stiff wire.

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4 Remove nuts (arrows) from constant velocity joint mounting
bolts at final drive. Pry constant velocity joint free from final
drive input flange at groove
(A).
- Hang driveshaft rear section from body using stiff wire.
< Do not let driveshaft hang unsupported, as rear CV joint rub-
ber boot (arrow) may be damaged.
4 Remove center support bearing mounting nuts (arrows)
- Remove driveshaft. Pull down on center of driveshaft to
facilitate removal.
CAUTIOI\C
Protect CVjoint with plastic cover.

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260-1 0
/ Driveshaft
Driveshaft, installing
- Prepare CV joint for reinstallation:
Extend joint to limit.
Clean off old grease and fill with fresh grease
Install new seal.
- Bend driveshaft slightly at center universal joint to install
CAUTION-
Do not allow CVjoint seal to become displaced.
- Align matchmarlts on driveshaft to matchmarks on final drive
and transmission flanges.
- Fit constant velocity joint to final drive input flange. Alternate-
ly tighten two opposite nuts to draw constant velocity joint
evenly into the final drive input flange. Once seated, tighten
down remaining nuts.
I CAUTION-
I Do not reuse self-locking nuts. These nuts are designed to be /
I used onlv once. 1
- Insert bolts in front of driveshafl to transmission output
flange. Counterhold each bolt while tightening nut.
CAUTION-
. Do not reuse self-locking nuts. These nuts are designed to
be used only once.
Avoid stressing the flex-disc when torquing the bolts.
Do this by counterholding the bolts and turning the nuts
on the flange side.
- Position center support bearing and install mounting nuts.
Use new self-locking nuts.
- Install heat shields.
- Install rear transmission support crossmember.
- Install exhaust system. See 180 Exhaust System.
Reconnect oxygen sensor wiring harnesses and reattach
wiring harness retainers to rear transmission support
crossrnernber.

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Driveshaft
- Road test vehicle to check for noise or vibration
CAUTION-
Do not reuse self-locking nuts. These nuts are designed to
be used only once.
Avoid stressing the flex-disc when torquing the bolts.
Do this by counterholding the bolts and turning the nuts
on the flange side.
Tightening torques
Alunlinum driveshaft to flex-disc
- MI2 (use coated washers)
90 Nm (66 ft-lb)
Driveshaft
CV joint to final drive flange
Mi0 (Tom bolt)
70 Nm (51 ft-lb)
M8 (compression nut) 32 Nm (24 ft-lb)
Flex-disc to transmission flange or driveshaft
MI0 (8.8 grade) 48 Nm (35 ft-lb)
MI 0 (1 0.9 grade) 60 Nm (44 ft-lb)
- Mi2 (8.8 grade)
81 Nm (60 ft-lb)
- MI2 (10.9 grade) I00 Nm (74 ft-lb)
MI4 140 Nm (103 ft-lb)
Transmission
crossmember
to transmission (ME) 21 Nm (15 ft-lb)
. to chassis (M10) 42 Nm (30 ft-lb)
NOTE-
Boltgrade is marked on the bolt head. When replacing bolts,
only use bolts of the same strength and hardness as the orig-
inals installed.
Flex-disc, replacing
- Checlc flex-disc between front section of driveshafl and trans-
mission output flange for craclts, tears, missing pieces, or
distortion. Check for worn bolt hole bores in flange.
- If flex-disc needs replacement, remove driveshafl as de-
scribed earlier.
- Unbolt flex-disc from driveshaft.
NOTE-
Removal andinstallation of the bolts may be made easier by
placing a large hose clamp around the flex-disc, and tighten-
ing the clamp slightly to compress the rubber.

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260-1 2
1 Driveshaft
Install new flex-disc using new self-locking nuts. Molded ar-
rows (arrows) on coupling should point towards flange arms.
4 On vehicles with aluminum driveshaft, use coated washers to
prevent contact corrosion.
- Counterhold bolts while tightening nuts.
Tightening torque
Aluminum driveshaft to flex-disc
M12 (use coated washers) 90
Nm (66 ft-lb)
Steel driveshaft to flex-disc
MI0 (8.8 grade) 48
Nm (35 ft-lb)
- MI0 (10.9 grade) 60 Nm (44 ft-lb)
Coated washers - MI2 (8.8 grade) 5027500 . Mi2 (10.9 grade)
M14 81
Nm (60 ft-lb) 100 Nm (74 ft-lb)
140 Nm (103 ft-lb)
- Install driveshaft as described earlier
Center bearing assembly, replacing
The center bearing assembly consists of a grooved ball bear-
ing in a rubber mount. The bearing assembly is pressed
the driveshaft.
- Remove driveshaft. See Driveshaft, removing
- Matchmark front and rear driveshaft sections before
separating.
Remove bolt (arrow) securing front and rear halves of
driveshaft and pull driveshaft apart.
- Remove shim and dust shield, where fitted
- Use puller to remove center bearing assembly from
driveshaft. onto

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- On installation, drive new center bearing firmly to stop.
Reassemble driveshaft using matchmarks made prior to
disassembly.
- Clean threads and install bolt securing driveshaft halves.
Use thread locking compound
LoctiteO or equivalent.
Tightening torque Driveshaft front half to rear half
(use thread locking compound) 97
Nm (72 fl-lb)
- Install driveshaft as described earlier.
Front centering guide, replacing
The front centering guide centers the driveshafl in relation to
the transmission. The guide is press-fit into a cavity in the
front of the driveshafl and slides onto the transmission output
shaft.
No specifications are given
forwear of the guide, but general-
ly the guide should fit snugly on the transmission output shafl.
NOTE-
Some driveshafts have a dust cap installed on the end of the
driveshaft, over the centering guide. The dust cap may be-
come bent or distorted when the driveshaft is removed or
in-
stalled. Damage to the dust cap should not affect the
centering guide and should not be mistaken for guide wear.
- Remove driveshafl as described earlier
- Pack cavity behind centering guide with heavy grease until
grease is flush with bottom edge of guide.
- Insert 14 mm (approximately 9/16 in.) diameter mandrel or
metal rod into guide. Strike guide with hammer to force cen-
tering guide out.
NOTE-
Tlie mandrel should fit snugly in the centering guide so that
the grease cannot escape around the sides of the mandrel.
- Remove old grease from driveshaft, lubricate new centering
guide with molybdenum disulfide grease
(MolykoteO, Long-
term8 2 or equivalent) and drive it into driveshaft.
4 When installing new driveshafl centering guide, be sure seal-
ing lip of guide faces outward. Drive guide into driveshaft to
a protrusion depth of
4 - 6mm (0.16 - 0.24 in.).
- Install driveshaft as described earlier.

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260-14
Driveshaft
Constant velocity (CV) joint, replacing
The CV joint at the rear of the driveshaft is available from
BMW as a separate part.
- Remove complete driveshaft as described earlier in this
section.
< Clean grease off CV joint. Remove retaining circlip (arrow)
from CV joint end of driveshaft.
- Drive out bolts from CV joint.
4 Remove CV joint from driveshaft:
Pry back protective boot
(A).
- Using BMW special tool 26 1 110 on inner race (B), press
or pull joint off shaft.
- Check protective boot for damage. Replace if necessary.
- lnstall new CV joint:
. Working from both sides of joint, inject approximately 80
grams of
OptimolB grease (or equivalent) into joint.
Install new sealing gasket on joint face that mates with pro-
tective boot. Seal fits in groove on outer race of joint.
Clean grease off driveshaft and mating splines on joint.
Apply
LoctiteO 648 to driveshaft splines.
Press new CV joint onto shaft as far as it will go.
CAUTIOI\C
Only press on inner CVjoint race.
- Install new retaining circlip to end of driveshaft,
- Insert CV joint mounting bolts. Be sure to reuse washers.
- Install driveshaft as described earlier in this section.