This is about a 2 hour job if all goes reasonably well
This procedure was revised in November 04. I used to split the outer joint with the axel in the car, the
rationale being that I didn't want to deal with the high torque of the center
hub nut. Turns out, though, that it's a lot easier to deal with the nut
than it is to deal with the snap ring that secures the axel into the outer
joint. This is particularly true of post-92 cars that, for some reason,
have extremely tight splines at the axel-to-outer CV joint interface; this can
make reassembly extremely challenging.
While most people won't have a torque wrench capable of the 206 to 221 foot
pounds of tightening torque specified for the wheel hub nut, I think it can be
estimated closely enough. It's much, MUCH easier to remove the whole axel
from the car, remove the inner drive tripod hub and replace the boot from the
inner end of the axel than it is to try to split the outer joint while it's
installed on the car.
A note on rebuilt axels: They're fine if you can find them AND if they
fit. I can never find them for the Saab 9000. Other people have
found what was claimed to be the right one, but they were too long, too short,
too something. Just be forewarned: They tend to be very scarce and they
too often are the wrong part - if you get one, check it carefully against your
original for correct length and size.
Special note added 08/20/06: I am damned sick
and tired of CV joint boots that only last 30 K miles!!! From now on I
will buy my boots from the Saab dealer; these aftermarket boots just don't last
long enough (well, some do, but who knows which ones?!) I think boots
ought to go closer to 100 K miles, although I'm not sure how realistic that
is. I do know that I don't replace CV joint boots for fun, and I'd rather
do it as seldom as possible. The infuriating thing is that if they split,
you're looking at a lot of money to replace the joint. 30 K miles is
pitiful, and I'm pretty pissed off about it, in case you can't tell.
- New outer CV joint boot kit (genuine Saab highly
- Boot clamps (one large, one small)
- Tube of grease
- New axel nut.
- I'm not convinced this is an absolute necessity, but it's cheap and
it's specified as a replacement item, so order it along with the boot,
clamps and grease
- Extra tube of CV joint grease to refill the inner joint
- because you're going to remove that boot too)
- New clamps for the inner joint (one small, one large)
- The small one is the same size as the small clamp for the outer
- The large inner clamp is an odd size, more like 3" than the more standard
- So don't expect your local chain parts store to have it
- You'll really want a new large inner boot clamp, 'cause it's almost
impossible to refit the old one
- Don't expect a nylon cable tie to be a suitable
sub - they usually can't be tightened enough and they usually
don't stay in place.
- Paper towels (lots) Picture of aftermath
- Rags (ditto)
- Degreaser/solvent (brake parts cleaner, acetone, or similar)
- Medium sized brush
- Wheel removal tools
- I prefer a breaker bar and deep 19 mm socket, or standard socket and
- 18mm 1/2" drive socket for the bottom strut clamp nuts
- 19 mm generally will suffice, particularly if it's a six point
- 1/2" breaker bar (preferred)
- 1 1/4 or 32 mm (I think) socket
- This is for the wheel hub center nut
- I used a 1 1/4", since it fit - I'm not positive what metric size
it should be
- Cheater pipe
- A 2 to 4 foot length of pipe that will fit over your breaker bar, to
provide extra leverage on the hub nut
- 17 mm box end wrench
- Various flat screwdrivers
- Expanding snap ring plier
- Needle nose pliers can be helpful with boot clip removal
- CV boot clamp crimping pliers (preferred)
- And/or the roll-up type, if that's the kind of clamp you have
- These tools run 6 to 10 dollars, and are worth the money
- A 250 foot-pound torque wrench is needed to do the job by the book, but I
make do with a 150 ft-lb one and estimate the final tightening torque of 206
to 220 ft-lbs for the hub nut. At the very least, you'll want a 150
ft-lb ratcheting torque wrench (very cheap ones - $25 or so - can be had
from Harbor freight or Northern Tool). The reason is that you'll need
to tighten the interference-thread-locking-nut at a pretty high torque rate
for several turns before it bottoms out. This would be tedious with a
non-ratcheting wrench and would stress a standard ratchet/cheater bar setup,
as well as being difficult to control
For the corner you'll be working on:
Remove the center cap from the wheel
Remove the center wheel nut
- The torque spec is 206 to 221 foot pounds. That means you'll
have to exert about 150 pounds of force on a standard breaker bar, not
taking into account the extra breakaway torque required, which can be
considerable. I was able to break mine loose with just the breaker
bar, but it was all I could do (I'm not as young as I used to be - favorite
anecdote). All I can say is, be careful and don't hurt yourself.
much safer to pull a wrench/breaker bar instead of pushing on
it. In this case, it would be nearly impossible to control the
wrench while pushing on it anyway. Best bet is to fit that cheater
pipe over the breaker bar, move out another foot or so, then pull
steadily and firmly, keeping your back straight and using your legs.
It might be a little tricky controlling it all until you get it loaded up,
but once you're got good pressure on everything, it should be easy.
- Then again, if you have an air wrench and a hefty enough compressor
(or an electric air hammer), you'll know exactly what to do!
- Once the center hub nut is broken loose, go ahead and use a ratchet to run
it out until it loosens up.
- Now loosen the four wheel bolts
- Jack the car up
- Install a jack stand
- I like to put mine under the rear support plate, just behind the rear
bushing of the lower control arm
- lower the car onto the jack stand. Leave the jack in place as a
- Remove the wheel
Remove the 18 mm nuts from the two bottom strut bolts. Picture
- The bolts (17 mm heads) enter from the rear and the 18 mm nuts are on the front side.
A 19 mm socket will generally work on the 18 mm nuts.
- They're pretty tight (57 to 77 foot pounds), so a reasonably long breaker bar is recommended
- Once broken loose, use a 17mm wrench to hold the bolt heads as you ratchet
the nuts off
- Drive the top bolt out.
- Drive the bottom bolt out using a hammer and screwdriver/whatever.
There will be some upward pressure exerted by the resistance of the control
arm bushings. It won't be much movement, but it's enough pressure to
require driving the bolt out
Pull the hub assembly piece out of the bottom strut clamp. Picture
Drive the axel out of the hub splines
- If you have a new hub nut (which you should), it's probably best to remove
the original hub nut, then reinstall it backwards to give yourself extra
surface to strike with the hammer. If you do this, run the nut onto
the axel until the the end of the axel is about an eighth of an inch shy of
the nut (Vice Grips help a lot here). The idea is to distribute the
load on lots of threads while still protecting the end of the
- It can take a good bit of whacking with the hammer to drive the axel loose
- When it's free, pull the hub/brake rotor assembly outward as far as
possible and pry/push the axel free to the front of the assembly.
Loosen the inner boot clamp
- If you have a replacement clamp, you can just pry the old one off.
If not, you'll need to save the original for reinstallation (a new one is
- Needle nose pliers work reasonably well for spreading the crimp in the
clamp - grasp one side and rotate it toward the center, then repeat for the
other side. A screwdriver can also be driven in to spread the
crimp. Pry the band off the tang when it's loose enough.
Remove the axel
- Grease will flow out of the joint when the boot comes loose, so put a
towel on the frame member underneath the inner joint (if you're doing the
passenger side, anyway).
- It's also a good idea to have a plastic baggie handy to slip over the
joint to catch most of the grease, and a rubber band to secure it.
Two people make this a whole lot easier.
- Put your fingers under the inner end of the inner boot and pry the boot
toward the outside of the car while rotating and pulling on the axel - at
some point, the inner boot should pop loose from the hub. Put the
baggie over the drive hub. Pull the axel assembly out of the car and
tilt the inner end up to avoid grease drippage.
- Carefully clean the dirt from the inside lip of the boot, then drain the
excess grease out.
Remove the tripod hub and inner boot
- The hole in the tripod hub is tapered, so it only wants to go on the inner
end of the axel one way. The steel is too damned hard to score with a
file or a chisel, so wipe it as clean as possible and mark it with a felt
- Using expanding snap ring pliers, spread and remove the snap ring/circlip.
It's light duty, so is pretty easy to remove.
- Use a gear puller to pull the tripod hub off the axel splines (it's a
pretty tight press fit)
- Try to keep it oriented/stored such that you won't have to rely on
markings to know which way it goes back on the shaft. This is with
respect to the face of the hub only, not the drive wheels. Note,
though, that if mis-handled, the wheels can pop off the stubs and
scatter the needle bearings - you don't want that to happen.
- Slide the inner boot off the axel, bearing in mind that grease will drip
out of the small end when you do so
Clean the axel shaft very thoroughly
- It's very, very important that dirt not get inside the boots
- Use brake parts cleaner, engine degreaser, acetone or whatever works best for you
- An old toothbrush works great for cleaning the interface between the small
end of the boot and the axel. You can also push that end of the boot
toward the big end a bit to get at the trapped dirt.
- A somewhat larger wire brush works well on the rest of the axel
Remove the outer boot
- Remove the clamps - you can pry the crimp open with a screwdriver
- Spray the axel shaft with silicone spray to allow the boot to slide freely
- While holding the outer end of the axel up, loosen the boot and slide it
off the axel, bearing in mind that grease will drip from the small end of
the boot when it is removed
Install the new outer boot
- Spray a bit of silicone on the small opening of the new boot
- Install the boot onto the axel, big end first
- Slide it up near the outer joint
- Fill the boot with the contents of a CV boot grease package
- Check the joint and boot for cleanliness, then slide the boot over the
- Install the new clamps.
- The alternate clamp style is a thinner metal band that wraps around the boot,
then goes between a couple of vertical tabs. You pass the end of the clamp
through a slot in a wind-up style clamp tool, then wind the tool until the belt
is tight, then you bend the tabs over to secure the band. I think there
are a couple of other tabs that allow you to bend the band back and
double-secure it. Then you cut the excess off. Something like
that. Sorry, but it's been a while since I installed one of those.
It should be evident enough - just make sure you get the right tool for it (ask
at the parts store). This type seems cheaper than the other type, but
sometimes it's easier to install (like on the big end of the inner boot on the
passenger side, which is almost impossible to get to with the crimp-style boot
Re-install the original inner boot and tripod hub
- If your inner boot has any cracks, replace it. Generally, though,
these boots pretty much last forever because they only have to flex
vertically, where-as the outer boots have to flex in all directions and with
every turn of the steering wheel.
- Slide the small end of the boot onto the axel
- Position the tripod hub with the marked face facing outward (remember, the
hole is tapered)
- You'll need to drive the hub onto the axel with a hammer (unless you have
a suitable press), but you don't want to pound directly on the hub because
you would probably hit the drive rollers, and that's a no-no. So find
a suitably sized socket to use as a driver interface, and hit it with the
hammer. Wrap your hand around the three drive wheels to keep them from
popping off and scattering the bearings. This is an excellent
opportunity to smash the bleeding the hell out of your hand with the hammer,
so all I can say is, use common sense and be careful. A good, large
vise would be really helpful. It takes quite a bit of whacking to
drive the hub onto the splines.
- When the outer face of the hub is past the groove for the snap ring,
spread and install the snap ring
- Fill the inner boot with the contents of a CV joint grease packet, then
slide the boot up over the tripod joint until the small end of the boot
snaps into its groove on the axel. Install the small-end clamp.
Re-install the axel
- Align the tripod drive rollers with the grooves in the driver cup, then
push the tripod joint into the drive cup - some axel rotation might help
- Push the big end of the inner boot onto the drive hub - rotating the axel
probably will help a lot in this step
- Spray the splines on the outer end of the axel with silicone, then
position the end of the axel into the hub splines. Rotate the
hub/rotor assembly to bring the splines into alignment.
- You can swing the front end of the hub assembly in to bang the axel into
the splines, but be gentle, to avoid damaging the tripod joint (it's
bottoming out in the drive hub when you do this, so do it gently and keep it
to a minimum). Make sure the axel is properly centered before you try
to drive it into the hub - rotation helps.
- Use a hammer to drive the hub/rotor assembly onto the axel shaft.
Hut the hub near the center, or the most central part of the brake rotor
(NOT the part of the rotor that is acted on by the caliper). It will
take a lot of hammer driving to get the axel to come through the outer end
of the hub (late models, anyway).
- When the axel comes through the hub far enough, install the nut and snug
it up a turn or two (the axel will want to turn, but quick wrench movements
should allow you to overcome the nut resistance enough to get it pulled up a
couple of turns). Leave the final tightening of the nut until the
wheel is back on the ground.
- Clean any grease off the brake rotor
Install the big clamp on the inner boot
- This can be a real bear, as there is very little room to work on the
passenger side. Note as of 09/04/06: Hey, guess what? There's
very little room on the driver's side too! Certainly not enough for
the standard crimping tool. This time I used a miniature pair of Vice
Grip pliers, tightening the screw just a little at a time and crimping
several times. You can also try using diagonal cutting pliers to crimp the
clamp, although I think the mini Vice Grips worked better. It's almost
impossible to correctly reinstall an old clamp on the inner boot on the
- You might want to try the wind-up type clamp on the inner
Reconnect the hub to the lower strut clamp
- Push the hub's mounting arm into the lower strut clamp
- Using a screwdriver or such to lever the holes in the hub into alignment
with those of the strut clamp, install the lower bolt from the rear and tap
it partway home
- Put the top bolt through the antilock cable brace plate, then lever the
top holes into alignment and start that bolt. Wheel position can make
a huge difference - try turning the steering wheel a ways toward the
- Align the antilock cable brace plate's fingers so that they fit onto the
horizontal surface of the strut clamp's sheet metal
- Hammer on a screwdriver or something to drive the bolts into position - to
avoid damaging the antilock cable assembly, do not hammer directly on the
- Hold the bolt heads with a 17 mm wrench and tighten the 18 mm nuts to a
torque of 75 ft-lbs (????) Y'know, I'm not sure where I got that torque
value. Not sure I believe it, either. Just tighten 'em good and
Reinstall the wheel and tire
- Position the wheel locating pin at the top or the bottom, whichever works
best for you. I prefer the bottom. Install the wheel, then
install and snug up the four wheel bolts.
- Raise the car, remove the jack stand, then lower the car
Now comes the fun part: Torquing up that big-ass hub nut!
- Yet another anecdote
- I recommend a 3" extension on the socket. A 2" one puts
your knuckles and the wrench right up against the fender. Longer than
3" will make the whole assembly want to tilt - makes it too hard to
grip the nut and apply good, even torque.
- If you have a 250 ft-lb torque wrench and a strong back, you're in
business. If not, you'll have to estimate 200 to 220 ft-lbs.
First, pull the nut down - this involves a lot of hard quarter-turn pulling
of the wrench, and it's pretty exhausting. The axel will protrude
through the nut quite a ways before it bottoms out - more than half an
inch. I used a 150 ft-lb torque wrench set to 150 ft-lb and kept
pulling until the nut started to offer serious resistance. At that
point I made sure to pull smoothly but deliberately until the wrench
clicked. I then replaced the wrench with a breaker bar and pulled it
another eighth of a turn. I feel comfortable with that, which is to
say that I think that's in the ballpark of how tight it ought to be.
The break-away torque to overcome friction and get the nut moving again is
considerable, but it should be done smoothly to get it right. Or, you
could just keep it moving another eighth turn without stopping after the
- Worst-case, if you should miss badly enough to cause the nut to some day
come loose and the axel manages to work itself out of the hub, you only lose
drive. And probably mess up the splines on the stub axel.
The wheel won't fall off or anything like that, because it's held in place
by the hub-to-strut bolts. I think you would have to miss the torque
by an enormous amount - probably a lot more than 50% - before it would
fail. And, at that, I think it would be more dangerous to drastically
over-torque than to drastically under-torque (if the nut breaks, it'll come
loose, but as long as it doesn't break, it's going to have a hard time
backing off because the threads appear to have designed-in interference to
make it a locking-type nut). Still, the designers obviously set a
torque spec for a reason.
- If you have the 250 ft-lb wrench, you can use a cheater pipe to make it
easier. The cheater pipe will help you pull 150 ft-lbs with the 150
ft-lb wrench, but it will still click at 150 ft-lbs, so take it that extra
eighth of a turn to finish it off.
Finishing up - tighten the four wheel bolts
- Don't forget to torque the four wheel bolts to 80 ft-lbs
- Install the center cap in the wheel, clean up and put up, and you're done
Check the boot after a couple of days, then after a couple of weeks to
make sure everything is going as it should.
- The clamps could slip or break
- Grease could leak
- The clamps could be loose or misaligned and allow the boot to slip off
Inspect the boots every six months, if possible. I've had cracked ones
go for six months without cracking any further, and I've had them split within
six months of discovering minute cracks. Best bet is always to replace
them as soon as you see any cracking developing. Boots are cheap. CV
joints are not. Rebuilt axels aren't too bad, but they just don't ever
seem to be available for Saab 9000's. And if you can find one, it's often
not quite the right part.