CV Joint/Boot FAQ



Generously maintained by Kevin Yankton ( yankton_kevin@amat.com)


The CV Joint/Boot FAQ is detailed as follows:

I - Introduction:
  1 - Information source, how to contribute to the FAQ, 
      how to get mistakes corrected...

II - General information:
  1 - Why is it important to inspect the boots?
  2 - What are some of the signs of a bad joint?
  3 - How about the split boots?

III - SAAB 9000:
  1 - CV Joint description/operation
  2 - Universal Joint description/operation
  3 - Drive shaft removal
  4 - Constant Velocity (CV) Joints
  5 - Inboard drive shaft joint (Universal Joint)
  6 - Drive shaft fitting

IV - SAAB 900:
  1 - CV Joint description/operation
  2 - Universal Joint description/operation
  3 - Drive shaft removal
  4 - Constant Velocity (CV) Joints
  5 - Inboard drive shaft Joint (Universal Joint)
  6 - Drive shaft fitting

Thanks to Larry Strollo who maintains the Snow Tire FAQ.  Given his 
excellent FAQ structure, I was able to quickly bring my FAQ to the 
pages of the SAAB Network.

---------- Introduction -------------------------------------------------------

The source of the majority of the information contained in this FAQ 
has been extracted from various technical sources, discussions with 
local mechanics, and postings to the SAAB Network.  Since so any 
people have contributed to the topic of CV joints in the SAAB Network
Archives, it proved impractical to give credit to all the appropriate
individuals.  This is in NO way the definitive answer on how to 
perform the procedure.  Rather, it is the summation of several 
different sources of information in an attempt to provide a resource
for people to draw upon when attempting to perform a repair 
themselves.  The suggestions given are intended to enhance your 
general understanding of your car's operation.  The repairs suggested
and the methods described, though they may have worked for others, may
or may not work for you car due to variations in models, equipment, 
and other unknown factors.  If you are still seeking the great Guru 
of the CV Boot, belly up to the bar and take your car to your trusted
local SAAB mechanic and have them do the repair for you.

If you see something here that you wrote, but is not attributed 
properly, or if I cite you and you don't want to be cited, send me an
E-mail (Kevin Yankton, yankton_kevin@amat.com) and I'll do my best to
address it.  Likewise, if you have clarifications, corrections, or 
further contributions, send me mail and I'll be happy to amend the 
FAQ.

Neither I nor Applied Materials, Inc. assumes responsibility for the 
accuracy of the information contained here.

Having said all that...


---------- General information ------------------------------------------
WHY IS IT IMPORTANT TO INSPECT THE GAITERS (BOOTS)?
	Eventually, dirt will enter the joint through the tears 
leading to joint failure.  With time and the action of the joint, the
rubber will begin to breakdown and small cracks will develop.  One 
factor which can typically lead to CV gaiter/boot failure is when bits
of gravel collect in the pleats of the gaiter causing small tears.  
This is especially a problem if you frequently drive on dirt or gravel
roads.  The inner universal joints can last significantly longer since
they are more protected from the elements and are not as subject to 
twisting action as the outer CV joints.
	The rubber gaiters should be inspected at every oil change to
be on the safe side.  At the most, they should be examined with every
minor service.
	I will try to refer to the rubber boots covering the joints as 
gaiters so that others who might be reading this do confuse this term 
with a reference to the back of the car.  I believe gaiter to be the 
more universal word.


WHAT ARE SOME OF THE SIGNS OF A BAD JOINT?
	Symptoms are reported as clunking/thumping at irregular 
intervals (mostly at the point where the drive train would go from
no-load to load, but not always), and most noticeably a shake or 
shimmy under heavy load at high speeds.  It is also reported to make
sounds when backing with the wheels turned sharply.  This was not 
typically reported to be a problem at low speeds, but more at high 
speeds (60+) when the turbo boost would build accompanied by a 
pronounced shaking in the front end.	I felt that I should also 
note that the clunking/thumping/clicking sound can also be caused by
any of the following: loose front suspension bolts, shifting in the
brake caliper, or shifting in the wheel bearing.


HOW ABOUT THE SPLIT GAITER/BOOT?
	A few people have used the boots with success, but the majority 
express concerns about using them.  Given the amount of grease used 
in the gaiter, it might prove to be a challenging task to keep the 
seam of the boot absolutely free of grease.  If grease were to enter
the seam while trying to glue the boot, it would not properly seal 
and a leak would eventually develop.

---------- SAAB 9000 -------------------------------------------------------
DRIVE SHAFTS AND DRIVE-SHAFT JOINTS:
	An extremely flexurally stiff intermediate drive shaft extends
from the right-hand side of the differential through an additional 
bearing bracket on the engine body.  It has therefore been possible 
to make the two outboard drive shafts identical and with the same 
geometry relative to the wheel.  The advantage of this design is that
the directional stability of the car can be maintained even during 
the hardest acceleration.
	The left-hand drive shaft is connected to the differential 
through a universal joint comprising a tripod fork on needle bearings
which slides inside a cup-type driver.  The right-hand drive shaft is
connected to the intermediate shaft in the same way.  These universal
joints are permanently lubricated with Esso (Exxon) Beacon/Nebula EP2
grease and are enclosed in rubber gaiters (boots) to prevent the 
ingress of dirt or moisture.  
	In my conversations with several lubricant suppliers, this 
type of grease appears to be an industrial grease which is sold only
in bulk quantities.  An acceptable substitute appears to be either 
the use of a heavy duty wheel bearing grease or use of CV joint 
grease.  Since the inner universal joint is not subject to the same 
rotational and heat stresses as the outer constant velocity joint, 
it makes it possible to use the heavy duty wheel bearing grease.  To
be on the safe side, it would appear that a conservative approach
would be to use the CV grease since it is produced to a higher 
standard.  Furthermore, you really do not want to have to replace
the inner joint because you saved a few cents on the grease.

CV JOINT DESCRIPTION/OPERATION:
	The constant velocity (CV) joints transfer the drive from the
inboard drive shafts to the outboard shafts on which the front wheels
are mounted.  The inboard end of the outer drive shaft is in the form
of a bell with spherical tracks, in which six balls transfer the drive
from a hub.  A circlip prevents axial movement of the shaft.  The CV 
hub, balls and outboard drive shaft are a matched set and the parts 
therefore cannot be replaced individually.  SAAB recommends that these
joints be packed with Mobil GS57C grease.  
	As with the Esso (Exxon) Beacon/Nebula EP2 grease discussed 
for the Universal Joint, this is typically distributed to 
industrial users in large quantities.  Numerous people have 
recommended either Castrol MS3 (dark gray grease) or Redline 
Synthetic CV grease.  Any grease with has been designated as being 
formulated for use in the CV joint can be used, but it is probably 
preferable to use a name band if possible.  DO NOT use the grease 
specified for the inboard Universal Joint for the CV joint.  As noted
above, the CV Joint is subjected to greater angular rotational forces
and heat from the brake which can lead to breakdown of the grease if 
not specifically designated for the CV joint.


DRIVE SHAFT REMOVAL:
#1 - Remove the hub cap and slacken the hub center-nut. I used a 32mm
regular socket that I bought from Sears for $7.  It takes a little 
elbow grease, but I was able to loosen the center-nut without causing
any damage to the nut or the threads.  I also used an 18" 1/2" socket
bar from the very same Sears.  Don't forget to loosen the lug nuts at
this time also since the hand brake for the 9000 locks-up the rear 
brakes, not the front.  NOTE:If you experience problems loosening the
nut, see the Alternative Method proposed in the 900 section below on 
CV Joints - Gaiter Replacement and adapt this to the 9000.
#2 - Jack-up the front of the car, support it on axle stands and 
remove the wheel.  Since the 9000 uses a MacPherson strut suspension
on the front, no wedge blocks are required as with the 900.
#3 - Remove the wing liner. Note: the factory manual says to do this.
My experience has been that I was able to do the job without having
to remove all those bolts which hold the liner on.
#4 - Unbolt the MacPherson strut from the steering swivel member and
detach the flexible brake hose from the clip on the back side of the
strut.  This includes both the upper and lower mounting bolts on the
strut.  Note: If you have ABS, this is a good time to unbolt the ABS
sensor so that it does not get damaged during the job.  I believe 
that a 10mm bolt holds it in.
#5 - Undo the clip on the rubber gaiter on the inboard universal 
joint.  Separate the two halves of the joint and fit a dust cover over
the gaiter and driver.  Note: You might want to put a rag or towel 
under the inner universal joint before you separate them because 
sometimes the grease has liquefied and quickly runs out like molasses.
#6 - Remove the hub center-nut and withdraw the drive shaft from the
steering swivel member.  To get the drive shaft out of the hub, I
used a rubber mallet and tapped on the end of the drive shaft 
extending from the hub.  It came out with a few hits.


CONSTANT VELOCITY (CV) JOINTS:
To Dismantle:
#1 - Remove all traces of grease from the joint.  Undo the clip on 
the rubber gaiter on the CV joint and slide the gaiter back along 
the shaft.  Note: Since I was in the process of replacing the gaiters
anyway, I just cut them off which was cleaner and gave me more room
to work.
#2 - Remove the circlip and withdraw the shaft from the CV joint.  
Removal of the CV joint from the drive shaft by releasing the circlip
can prove difficult.  What works for me is to put the drive shaft in
a vice with the shaft tilted at a 45 degree angle and the CV joint on
the bottom.  Take a flathead screwdriver and wedge it between the arms
of the circlip so that the circlip arms are pinned against the bearing
wall.  With the circlip in the widened/open position, take a hammer 
and tap on the joint assembly and the shaft should slide out of the 
joint.  You may have to strike it firmly, but avoid having to pound 
on it hard as this may damage the joint.

To Assemble:
#1 - Pack the CV joint with 80g of Esso Nebula EP2 grease.  See 
general discussion of CV joint for alternative greases.
#2 - Insert the shaft in the CV hub, making sure that the circlip
inside the hub snaps into place in the groove in the shaft.  Pull the
shaft to make sure that it is held securely by the circlip.
#3 - Slide the rubber gaiter back into position and secure with the
clip. NOTE: If you are also replacing the gaiters, see the section
below titled "To Change the Rubber Gaiters."


INBOARD DRIVE-SHAFT JOINTS (UNIVERSAL JOINT):
To Dismantle:
#1 - Remove all traces of grease from the joint.  Remove the circlip
and pull the joint off the shaft.  I found the removal of this joint
to be difficult.  The clip came off easy enough, but the joint would
not move.  For installation of a new gaiter on the inner universal 
joint, I just slid the gaiter down the shaft from the CV joint side 
taking care not to tear the gaiter in the process.

To Assemble:
#1 - Check that the rubber gaiter is not cracked or perished.  If it
is, replace it.
#2 - Fit the universal joint into the shaft.  Pack the gaiter with
60g of Esso Beacon EP2 grease.  See general discussion of Universal
joint for alternative greases.

Caution: Take care to keep the grease off all painted surfaces, as 
the grease is liable to discolor the paint.

To Change the Rubber Gaiters:
#1 - Remove all dirt from the external surfaces of the gaiters and 
make sure that the joint is also free of the old grease.  Cleaning
the old grease from the joint is important because this will also
remove any dirt which might have become mixed in the grease.  The
abrasive material like dirt leads to the eventual failure of the 
joint.  Separate the inboard universal joint.  Undo the clips on the
gaiters and slide them off the shaft.
#2 - Fit the new gaiters and assemble the inboard universal joint.  
Pack the joint with the appropriate grease. NOTE: When fitting the 
new gaiter over the joint, the grease tends to form a seal, so squeeze
the air out by pressing down the narrow end to enable you to get the 
big end fully over.  This is essential since the clip or cable tie 
sits in a groove machined in the joint body. DO NOT USE the "jubilee"
type clips to secure the gaiter as they will tear the gaiter.


DRIVE SHAFT - FITTING:
#1 - Fit the drive shaft into the steering swivel member.
#2 - Fit the inboard universal joint and tighten the clip on the 
rubber gaiter.
#3 - Fit the bolts securing the MacPherson strut to the steering 
swivel member and fit the flexible brake hose to the clip on the 
strut.  Tightening torque for the bolts securing strut to the 
steering swivel member: 78-105 Nm (56-75 lbf). Note: Hold the bolt
 and tighten the nut.
#4 - Fit the thrust washer and the hub center-nut.  Tightening torque
for the center-nut: 270-290 Nm (195-208 lbf).
#5 - Fit the wing liner and the wheel.  Remove the axle stands and
lower the car.  Tighten the wheel bolts to the specified torque.  
Tightening torque for the wheel bolts: 105-125 Nm (76-90 lbf).



---------- SAAB 900 -------------------------------------------------------
DRIVE SHAFTS AND DRIVE-SHAFT JOINTS:
	The outboard drive shaft and hub assembly is journalled in a
double-row, angular-contact bearing in the steering swivel member.  
The bearing is permanently lubricated and has integral seals.
	The hub is splined to the outboard drive shaft and secured by
means of a center-nut which has a locking tab that is upset in a 
groove in the shaft.  A fully metallic tab locknut is used as on M88.
	The inboard end of the outboard drive shaft is connected to
the intermediate drive shaft via a constant velocity (CV) joint.
	The rear-wheel hub on M79/82 cars is mounted in two taper 
roller bearings, with the inboard bearing having a larger diameter
than the outboard one.  A removable seal is fitted between the hub
and the shaft.  A double-row, angular-contact bearing was introduced
during MY82.
	The bearing, shaft seal and hub are removed and fitted as an 
assembly.


CV JOINT DESCRIPTION/OPERATION:
	See description for 9000.


DRIVE SHAFT REMOVAL:
#1 - Place a spacer under the upper wishbone before you take the 
pressure off the springs when you jack it up.  Anything from 15mm 
wood blocks to pieces of old pipe will work.
#2 - Loosen the hub center-nut.  Several people have noted that they
have had difficulty loosening the center-nut because of the 
tightening torque and the LocTite used to hold the nut in place.  
Some have had the thread on the shaft come away with the nut.  If 
you belive this could be a problem for you, SEE ALTERNATIVE METHOD 
UNDER CV JOINT - GAITER REPLACMENT.
#3 - Raise the car.  Remove the front wheel and hub center-nut.
#4 - Release the clip securing the rubber gaiter over the inboard
universal joint.  Cars with ABS breaks should unbolt the wheel sensor
and tuck the lead out of the way.  A zip-tie can be used to make sure
that it is not damaged during the repair.
#5 - Undo the securing bolts for the upper and lower ball joints on
the wishbones.
#6 - Pull the steering swivel member away from the lower wishbone and 
swivel it up to enable the drive shaft to be withdrawn.
#7 - Withdraw the drive shaft and fit covers to the rubber gaiter and 
inner driver cup.


CONSTANT VELOCITY (CV) JOINTS:
To Dismantle - 
Note: When dismantling the CV Joint, use plastic covers to keep dirt
and dust out of the joint.
#1 - Remove the grease from the joint.  Kerosene or brake cleaner can
be used to clean the grease out.
#2 - Release the clips and slide the rubber gaiter back down the 
shaft.
#3 - Open the circlip and pull the shaft out of the joint.  
NOTE: Earlier models used a combination of spherical washers, spring
washers, and a circlip.  The CV Joint can be released by first 
pressing the drive shaft into the joint, releasing the circlip, and
then withdrawing the drive shaft.

To assemble -
#1- Pack the joint with about 80g of Esso (Exxon) Nebula EP2 grease.
See the 9000 Universal joint description for a discussion of other 
acceptable greases.
#2- Insert the drive shaft in the hub, ensuring that the circlip snaps
into place in the groove in the shaft.  Check that the circlip is 
properly seated by applying a sharp outward pull to the shaft.
#3- Fit a new boot (gaiter).  Tighten the clips: if you are fitting
new clips of the non-screw type, fit them by crimping the metal band
inward.  Take care not to damage the rubber.  For fitting and removal
of the new clips, SAAB recommends a special tool, Knipex 1099 pliers
supplied to SAAB dealers through Oetker.  DO NOT USE the "jubilee" 
type clips as they will tear the gaiter.

To replace CV Joint Gaiters (Boots) -
Note: Take care to remove all dirt and dust particles.
#1 - Remove the CV joint.
#2 - Undo the clips and remove the gaiter from the shaft.  To undo the
clip, pry the end of the clamp up with a screwdriver than grip the 
loose end with a pair of pliers.  Bend it over and off of the locking
hooks.  Alternatively, the clamp can be removed by snipping through 
the ear with a pair of side-cutters.
#3 - Fit a new gaiter.  Secure the boots to the joint with either a 
SAAB type clip or a zip-tie.  Tighten the clips: if you are fitting 
new clips of the non-screw type, fit them by crimping the metal band
inward.  The ear of the clip must be clamped closed to obtain a proper
seal.  Take care not to damage the rubber.  For fitting and removal of
the new clips, SAAB recommends a special tool, Knipex 1099 pliers 
supplied to SAAB dealers through Oetker.  DO NOT USE the "jubilee" 
type clips as they will tear the gaiter.
#4 - Fit the CV joint.
#5 - Pack the joint with 80g of Esso (Exxon) Beacon EP2 grease.  See
the 9000 Universal joint description for a discussion of other 
acceptable greases.  NOTE: When fitting the new gaiter over the joint,
the grease tends to form a seal, so squeeze the air out by pressing 
down the narrow end to enable you to get the big end fully over.  This
is essential since the clip or cable tie sits in a groove machined in
the joint body.

Alternative Method Suggested for Replacing the Gaiters - 
This method leaves the CV joint in the hub assembly and detaches the 
drive shaft from the hub.  Thus, avoiding the problem of not being
able to remove the hub center-nut.  (I have not actually attempted
this method, so the following is mainly based on the suggestions of
others.)
#1 - Apply the hand brake and jack-up the car making sure to use axle
stands.  NOTE:  As with the standard procedure above, you can insert
wedges under the upper wishbone to allow yourself more of an angle 
to work with and make removal of the drive shaft easier.
#2 - Remove the wheel.
#3 - Undo the ball joint on the track rod end, threading the nut back
onto the end of the bolt to protect the threads.  When splitting the
track rod end ball-joint taper - use a "tighten-up" type splitter and
not the "tuning fork" type.
#4 - Remove the brake caliper and hang it out of the way.  Note: I 
have found that an old milk crate or the like works well to hold the
brake while you work.
#5 - Find the end of the ABS sensor cable, unplug it and withdraw it.
In order to do this, sometimes you might have to remove the rear 
section of the wing liner.
#6 - Undo the pinch bolt on the ball joint on the wishbone.  If the 
bolts are frozen, an alternative method is to disconnect the lower 
wishbone arm from the body of the car.  The purpose of this procedure
is to allow the hub assembly to swing out of the way.
#7 - Remove the two bolts securing the steering knuckle to the 
suspension strut.  You can use a jack and adjust the amount of 
support offered by the jack to make sliding the bolts out easier.
#8 - Undo the clip holding the gaiter on the inner universal joint.
#9 - Withdraw the drive shaft/universal joint assembly from the driver
cup.
#10 - Undo the clip holding the inner gaiter to the shaft.
#11 - Remove the circlip holding the universal joint in place.
#12 - Remove the inner universal joint complete with the rubber boot,
retaining the grease inside.  Some grease may leak out as the grease
may have thinned with time.
#13 - Undo the clips holding the outer CV gaiter and slide the gaiter
off the end of the shaft.
#14 - Clean the shaft to remove any dirt that may have accumulated so
that it does not get inside the new gaiter as you slide it down the 
shaft on re-installation.
#15 - Slip on a new gaiter, pack the joint with new grease.
#16 - Reassemble in reverse order.


INBOARD UNIVERSAL JOINT:
To Dismantle:
#1 - Remove the grease from the joint.
#2 - Remove the circlip.  Note: The latest drive-shaft variants 
incorporate a stop for the driver cup instead of a circlip.  This 
comprises a taper on the shaft and a corresponding taper on the 
driver-cup splines.  The latest variant of the driver cup must be 
fitted to drive shafts of the latest variant.  However, the new 
drive-cup may also be fitted to early-variant drive shafts.  In the
newer design, the drive shaft uses a tapered shoulder as an inner stop
for the universal joint spider, replacing the lock ring previously 
used. New drive shafts are fitted in production to the following cars:
Cars with Scandinavian specification with effect from chassis nos.: 
AC1022347, AC2007941, AC3007195, and AC6001952.  Cars to 
non-Scandinavian specifications with effect from chassis nos.: 
AC1005904, AC2001784, AC3001770, and AC6000001.#3 - Pull the joint
off the shaft.

To Assemble:
#1 - Slide the joint onto the shaft and fit the circlip.
#2 - Pack the boot with 60g of Mobil GS57C grease.

To Replace Universal Joint Boots (Gaiters) -
Note: Take care to remove all dirt and dust particles.
#1 - Undo the clip on the driver-cup end of the boot.
#2 - Remove the shaft assembly.
#3 - Remove the inboard universal joint.
#4 - Undo the clip at the shaft-end on the boot and pull the boot 
off the shaft.
#5 - Fit a new boot.  Fit clips as noted for the CV joint. DO NOT USE
the "jubilee" type clips as they will tear the gaiter.
#6 - Pack the gaiter with 60g of Mobil GS57C grease. NOTE: When 
fitting the new gaiter over the joint, the grease tends to form a 
seal, so squeeze the air out by pressing down the narrow end to enable
you to get the big end fully over.  This is essential since the clip
or cable tie sits in a groove machined in the joint body.
#7 - Fit the shaft assembly.
#8 - Fit the universal joint.
#9 - Fit the clip at the driver-cup end of the gaiter.


DRIVE SHAFT - FITTING:
#1 - Remove the temporary covers from the driver cup and rubber 
gaiter.
#2 - Pack the driver cup with 115g of Mobil GS57C grease.
#3 - Insert the shaft in the driver cup.
#4 - Tighten the clip on the gaiter on the inboard universal joint.
#5 - Insert the drive shaft in the steering swivel member.  Reconnect
the steering swivel member to the lower wishbone.
#6 - Fit the bolts securing the ball joints on the upper and lower 
wishbones.  Tightening torque: 40-54 Nm (29-40 lbf ft)
#7 - Screw on a new hub center-nut, finger tight initially.  For cars
with ABS brakes, refit the wheel sensor at this time.
#8 - Fit the wheel and lower the car.  Tightening torque for wheel 
bolts: 105-125 Nm (78-86 lbf ft)
#9 - Tighten the hub center-nut.  Tightening torque: 280-300 Nm 
(207-222 lbf ft)
#10 - Remove the spacer tool from under the upper wishbone.

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