Estimating clutch disc wear.
Clutch replacement is a good weekend job. It could be done in a day (it took me 6 to 7 hours total labor to get the trans out and back in, and an hour or so of general clutch parts labor). It sounds like an awful lot of work, but it's really not a bad job at all. Mostly it's just a matter of peeling back layers and most of it is pretty easy.
A warning about slave cylinder differences.
Be advised that you will need to take the flywheel to a machine shop to have the face ground smooth, so you'd need to schedule that with a shop that's open on Saturday if you're shooting for a weekend clutch replacement. If you want to pop for a brand new flywheel, you won't have to worry about that. Resurfacing will generally put a flywheel back in as-new condition if the starter motor hasn't been malfunctioning (poor engagement can chew up the flywheel teeth) and assuming that the clutch rivets haven't chewed up the flywheel face (I suspect you lose clutch traction before that can happen, but I'm not sure).
I replaced my (91) clutch at 105 K miles. Clutch wear is judged by the distance of the dust cap from the face of the slave cylinder. It's 11 mm on a new one and 2 mm is the end point, so that's a total travel of 9 mm. Mine was at 6 mm, so it still had about four ninths left. I estimate that the disc could have gone as far as 150 K, but the operation of the clutch generally gets pretty ragged by 100 K due to glazing of the disc surface, hot spots on the flywheel and pressure plate, glitches in the hydraulics and noise from a worn release bearing. In my case, the release bearing has been noisy for two winters, the clutch has become increasingly chattery and rough (hot spots/glazing), engagement has been progressively less precise and the first clutch release in the morning was always a sudden pop, with no control over smoothness (sticky slave cylinder?) Replacing the clutch at 100 K might be a little premature from a pure wear standpoint, but you sure will like the difference in the operation. Mine is buttery smooth now. For some reason, the engagement height increases somewhat with new parts, and that takes a bit of getting used to, but it sure is smooth and precisely controllable.
I recommend doing it all if you're going to do any of it. My advice is replace the pressure plate, the disk, the slave cylinder and release bearing (they come as a set) at a minimum. Whether to replace the rear main seal or not is a very tricky question, if it isn't leaking. (If It Ain't Broke, Don't Fix It?). My harrowing experience. I think it's wise to go ahead and replace the master cylinder, as well; they don't last forever. Also, definitely have the flywheel resurfaced. Replace the pressure plate, not because it gets weak (they generally don't), but because there's no way to resurface them. Besides, asking another 100 K from a pressure plate is asking a lot. The flywheel and pressure plate surfaces need to be free of glazing and hot spots; otherwise, clutch chatter will result. Once you're in there, replacing the slave cylinder and release bearing is pretty much a must. Oh, it's a good idea to replace the shifter coupler while you're at it (at least in the earlier models).
It's good practice to put all bolts and nuts back where they came from so you don't lose them and you know where they go. In the case of the subframe, you'll have to put some of the the bolts and nuts back into the subframe after it's been removed. It's also a good idea to label all electrical and vacuum connections using string tags or whatever you prefer. All this takes a little extra time, but it can save an enormous amount of time and grief later when you discover that you don't know where the hell something is supposed to go.
Special tools required:
This is for a 91, amended for the 94 and later (yes, folks, I've had to drop trans for both). I have modified the order of some of the steps (as opposed to the factory Saab manual) because I found that some of their sequence did not seem to be very well thought out.
Here's a step-by-step quick checklist.
And here are the details:
Jack the front of the car and support it solidly on jack stands. Make sure the stand on the driver's side is behind the suspension attachment point and the suspension bracket, as you will need to remove these parts. You'll have to support the car by the floor, the side rail and the jack-attachment fixture, and you'll need to spread the load to do it successfully and safely. I used a piece of 3/4" plywood about 18" square. Picture
Disconnect the negative battery cable from the battery, then the positive cable, then remove the battery.
Pre-94 cars: Remove the washer fluid reservoir (10mm bolt at top rear and 10mm bolt at bottom front). Pull the windshield washer pump out of the reservoir. You might want to siphon the washer fluid out first; otherwise, just lift it out, stem the flow out of the pump hole and transfer the fluid to another container.
Open the cover on the terminal block on the front of the battery holder (squeeze the cover to release it). (NOTE: the plastic terminal block cover and housing on my 94 were so heat damaged that they disintegrated when I disassembled them - be prepared to deal with it.) Pre-94 cars: removing the washer fluid reservoir first gives you better access here). Label the wires so you'll remember where they go. Screw the nuts back onto the terminal block.
Remove the battery tray. There are 4 bolts (13mm) on the side; the bottom front one is under a wiring duct and is not easy to see. Pre-94 cars: There's a 10mm at the bottom back of the holder, nearest the fender. 94 and later: There is an ECU mounted to the back of the battery holder. If you push the upper radiator hose out of the way, you can pull the whole battery holder assembly up and then swing it back out of the way without disconnecting the ECU. If you prefer to remove the ECU, it's secured with two Torx screws at the top. Picture
Release the 3 clips on
the air filter housing at the fender well and the 2 clips on the other end of
the air mass meter. Disconnect the electrical connector from the air mass
meter (AMM). Push the AMM toward the turbo, compressing the rubber duct that goes to the turbo,
then maneuver the
air mass meter (AMM) out of the air cleaner duct, angling the AMM toward the
rear. This can be exasperating, but work carefully;
the AMM is somewhat delicate and expensive. Compressing the duct that goes
to the turbo is the key. Put the AMM in a safe place. Remove the air cleaner duct.
It probably isn't necessary to remove t he filter element, but now is a good
time to inspect it and replace if necessary. The duct to the turbo has to
be compressed and/or bent to the side to remove the air filter.
94 and later: The plumbing is different (much simpler), as they use a manifold absolute pressure (MAP) sensor instead of an AMM. I just left all the inlet plumbing in place, and it did not get in the way.
Remove the aluminum pipe that goes from the intercooler to the throttle body. I didn't do this on the 94 Aero because the upper radiator hose was more in the way than the inlet pipe was. I did take the pipe out of the upper coupling to allow a bit more room, then I just worked around the hose and inlet pipe. It may or may not be advantageous to remove it from earlier cars. In any case, it isn't very difficult to remove:
Remove the center and drivers-side plastic underpanels (front, underneath the car). 8 mm bolts on earlier models, I think, and 10 mm bolts on later models. Remove the fender trim piece and both parts of the fender liner. Picture NOTE: On the 94, I removed only the front half of the fender liner and that was fine (probably would be the same on the earlier models - maybe I just went overboard on the 91???).
Disconnect the backup light switch connector on the end of the transmission, at the top.
Disconnect the battery ground cable from the end of the transmission, at about the middle.
Pinch off the slave cylinder hose and disconnect it from the union atop the transmission. You can buy special pinch-off pliers or you can rig something up with Vice Grips or a C-clamp. Picture
Disconnect the speedometer cable. Get on top of the engine and look down behind it. Picture On later models (90 onward?) the "cable" is a wiring harness.
Pre-94 cars: Working from the same position as for the speedo cable, disconnect the shift rod coupler. Only the two inner nuts need be reomoved. If you're going to replace the coupler (damn good idea, you know), it's easier to leave the outer two nuts until the transmission is removed. 94 and later have a different style of shift coupler that gets disconnected later.
Remove the starter motor (Pre-94 cars: This is probably the most difficult part of the clutch replacement procedure)
Now that all the working-from-the-top-of-the-engine stuff is done, it's time to support the engine from above:
Undo the transmission mount bolt, underneath. It's a 14 mm bolt head and 17mm nut. Knock the bolt out, gather up the two tabbed washers and nut, assemble them and tag them.
Remove the nut and bolt that hold the lower ball joint stud to the hub/steering knuckle assembly (17mm bolt head, 16mm nut). 16 mm is a bastard size; a 5/8" socket works fine.
Remove all but one of the nuts/bolts that hold the transmission to the engine.
Time to remove the half of the subframe that's on the driver's side of the car. This is a fair amount of work, but it's all pretty easy. Here's an overview of the attachment points.
Use a screwdriver to pry off the "e" clip from the top of the ball joint stud. Picture
Slacken the two pivot bolts/nuts on the subframe.
Remove the 17mm nut from the bottom of the sway bar link. Remove the two 10mm bolts that hold the sway bar bracket to the subframe. Turn the steering wheel full left to gain the best access to the front bolt. Picture
Remove all the bolts and nuts that secure the subframe, leaving the outer front ones until last. See the checklist. NOTE: To get to the nuts atop the steering rack on the two bolts at the rear attachment point (near the hinge point), go in from the wheel well - it's easy to get a wrench on them from there (nigh-impossible from underneath).
Just as a backup, position a jack under subframe and apply slight jack pressure to the subframe to make sure it's securely supported. The engine support should hold the engine, but let's proceed on the side of safety, just to make sure all is as it should be. When ready, remove the final bolts and release the jack a bit. You might have to hammer or lever the subframe a bit to release the ball joint stud from the wheel hub assembly. Make sure the e-clip is removed from the top of the ball joint stud. The object is to free the subframe and let it swing down, while assuring yourself that the engine is properly supported from above. The subframe itself isn't all that heavy. It could hurt you if it swung down on your head, but it's certainly easy enough to control. Of course it's always best to work from the outside of the car until you know everything is kosher.
The manual says to leave the subframe attached but swung down, but that's nuts! Remove the two pivot bolts/nuts, then drop the subframe down and get it completely out of the way. You can remove one bolt, then support that end with your foot while you remove the bolt at the other end. I recommend you put all the bolts back where they came from, keeping the bolt/nut assemblies with the subframe and screwing the bolts back into their frame holes.
By the way, there was a sheet metal spacer plate on my car that went between the suspension and the body, at the front of the suspension bracket. I recommend you use the bolts to align it and go ahead and glue it into place against the body with some sort of fairly compliant glue (contact cement or silicone or something). This keeps you from losing it or forgetting to reinstall it. The hump goes up, matching the hump in the body.
94 and later: Loosen the 8 mm nut from the inner end of the taper pin on the shift coupler to give maybe 3/32" (couple of mm) of clearance between it and the coupler. Now whack the nut with a hammer to knock the taper pin loose, then remove the pin.
Clean the inner driver's side CV (tripod) joint boot as thoroughly as possible. Position a clean drip pan beneath the joint. Have some plastic baggies and rubber bands ready to cover the joint and hub. Remove the clamp from the inner joint boot, then pull the hub/axel assembly outward to release the joint. Manage the grease as best you can and fit the baggies over the joint and hub, securing with rubber bands.
Position an engine hoist over the transmission and connect the boom to the transmission lifting eye. The best plan here is to use a bolt, nut and washers to secure the lifting chain directly to the top side of the trans lifting eye. Because the eye is bent, this will allow the end of the transmission to drop slightly, and you need that to happen so the end of the trans can clear the brake hose connecting nuts on the ABS/master cylinder assembly. Raise the boom of the engine hoist up high first, and use plenty of chain so you can lower the trans all the way to the floor. 94 and later: They did away with the damn lifting eye. IDIOTS! (I'm just about to drop the trans out of my 94 Aero, and I am not pleased to discover that they have eliminated the perfectly bent lifting eye). You'll have to fashion something and secure it with one of the intermediate transmission housing bolts.
Take up the slack, then remove that last trans-to-engine nut. Lower the lift boom just a tad, enough to let the end of the trans drop an inch or so, and the transmission should slide right out when you pull outward on the chain and trans. The key is to drop the end of the trans enough so it will clear the ABS connections. You can see all this from the fender well.
Once you get it disengaged (you might have to shake it, jerk it or lever it a bit), check to see which end of the intermediate shaft came loose. It's a steel driveshaft surrounded by an aluminum tube, on the passenger side. Picture If it stayed connected to the trans, you'll want to crawl underneath and remove the tube and shaft - just pull them loose from the trans. Plug them back into the intermediate bearing support, or set them aside for the moment. Now you can lower the trans straight down with no interference.
Remove the six 13 mm clutch bolts
Remove the flywheel bolts.
Install the new slave cylinder onto the transmission. Make sure you get the seal in there, and lube it with grease or oil first.
Rear main seal
OK, so is the rear seal leaking? If so, replace it. If not ... you make the call. I was not successful at it. My harrowing experience, in case you missed it earlier. If you decide to do it, pry the old one out with either a screwdriver or a seal removal tool. The screwdriver probably works as well as anything. Picture Grease the lip of the new seal. Make sure the retainer spring is in place all the way around. Install it however you can.
Once the seal is fitted to your satisfaction, reinstall the resurfaced flywheel. Make sure that the sheetmetal pieces are installed on the rear of the engine first; they cannot be installed after the flywheel has been installed!
One hole in the flywheel is slightly smaller than the others, and it won't have a ring around it (due to no bolt head) - this is the one that goes onto the locating dowel; make sure you get the right one on the dowel. Put a thread locking liquid onto the end 1/2" of each bolt, then install the bolts. I used blue Locktight. Torque the bolts to 44 foot pounds, using an opposing pattern (torque one, then torque the one opposite it). You'll have to jam the flywheel using a screwdriver in the ring rear teeth and levering against a lower transmission bolt. I couldn't wedge it in, so had to hold the screwdriver with one hand and pull the wrench with the other. Another hand would be nice here.
Clutch alignment and assembly
Thoroughly clean the faces of the flywheel and pressure plate. A spray brake cleaner works best for this. Don't use anything that would leave any oily residue. It's always a good idea to slip the clutch disk onto the transmission shaft, just to make sure they sold you the right thing, and that the splines do indeed mesh. If you ever get bit by this so much as once, you don't ever want to get bit by it again! Yes, I did get sold the wrong clutch disc once and I spent a couple of hours trying to get a trans back into an MGB before I disassembled the clutch and found the wrong (too small) spline opening in the disc.
Now put the new clutch disc against the pressure plate with the raised center hub toward the pressure plate. Need pictures? Look at the pressure plate and find the three holes that will fit onto the flywheel's locating dowels. They're easily lost in the array of balancing holes, but the locating holes are slightly closer to the center of the pressure plate than all the other holes. Picture. Slip the clutch alignment tool into the center hub of the disc, then place the whole assembly onto the three dowels on the flywheel. Install a couple of bolts finger tight to hold the assembly in place. Push the tapered end of the alignment tool into the center hole in the flywheel. Picture You shouldn't be able to move the tool much, and you can center it by feel (it's pretty much entirely self-centering). The clutch should now be aligned. Install all the clutch bolts finger tight and recheck alignment. Cross-tighten the six bolts a half turn at a time (first one, then it's opposite, working through the tree pairs). You can remove the clutch alignment tool after the first half turn. Continue until all are just snug, then torque to 18 ft-lbs (barely more than snug).
Here's a step-by-step quick checklist.
A second person always helps here, but it can be done alone.
Are you replacing the shifter coupler? If so, now's the best last chance to do it. The outer bolts are easily accessible now.
Position the transmission under the car. Using a bolt, nut and large, heavy washers, attach the lifting chain to the top of the transmission lifting eye.
Make sure the intermediate axel and its housing are installed in the bearing support on the passenger side of the car.
Remove all transmission mounting nuts from the studs and bolts.
Carefully raise the transmission up to installation height. Keep the outboard end lower than the clutch end (this should occur naturally if the lift lug is installed properly - it's bent to induce some tilt in the transmission when it's lifted). This tilt allows the end of the trans to just clear the ABS plumbing. Picture. Guide it onto the top mount studs. Make sure no cables or hoses get pinched between the trans and engine. Getting it to go into place involves fiddling and patience. Sometimes it will slip right in, other times it takes coaxing. Sometimes a good kick from the end will do the trick. If you can get it onto one of the top studs far enough to install a nut, do so. Then push, shake nudge, whatever, until it slips into place. Turning the flywheel a bit may be helpful. Check the alignment of the intermediate driveshaft from below, although it generally finds its way home without help. If the transmission refuses to slip home, then the clutch may not be aligned properly, although if you used even the crudest tool, this should not be a problem.
Once the transmission slips home. install one of the top nuts. Check to make sure the intermediate shaft is properly mated, then install all of the trans nuts and bolts.
The larger of these should be torqued to 60 ft-lbs. You probably can't get a wrench on some of the smaller ones, so just tighten them good and tight. I could not torque the one under the starter without denting the intermediate shaft protective tube. I recommend you just use a box-end wrench.
Make sure there's plenty of new grease in the inner CV (tripode) joint (buy CV joint grease; I've read that mixing regular grease with CV joint grease is not a good thing to do). Fit the driver's side driveshaft to the drive hub, rotating the wheel hub to line up the tripode joint with the hub sockets.
Position the subframe on the floor under the car. Slide underneath, beside it. Remove the hinge bolts and put them where you can get to them. Slide your leg under the rear of the subframe, pick up the front and arm-and-leg-lift it into place. Tentatively install the front bolt, then slide back and install the rear bolt. Run the nuts up toward snug.
Did you glue that spacer plate in place at the front of the suspension bracket? If not, you'll need to remember to install and align it before things get too far along.
Remove all the nuts and bolts from the subframe and the frame, and position them on the floor, relatively close to their installation points. Make sure the e-clip is removed from the ball joint stud too. Rotate the subframe upward and position a jack under it at the front corner. Jack it upward, aligning the sway bar link with its corresponding hole as you go.
The trans mount just loves to get all hung up on the corresponding mount tangs on the subframe. Keep an eye on it, and lever the mount into the tangs with a screwdriver as they start to engage.
Keep it coming up (watch that mount, it can still get tangled) and guide the ball joint stud into its hole in the wheel hub housing (did you remove the bolt and nut so the stud could go in?). You'll probably have to drive the stud into its mount hole by banging on it from beneath.
By this time you ought to be able to start installing bolts. Once you get some in place, you might want to position the jack under the suspension mount to help get it up into position. You can then fit the suspension bracket.
As it all comes together, lever the subframe and wheel hub to align the ball joint stud so the bolt can be installed.
Loosely install all fasteners. Once all are installed, torque the subframe bolts to 40 ft-lbs. Torque the ball joint clamp bolt to 20 ft-lbs, then install the e-clip.
Tighten the subframe hinge bolts good and tight. Try around 30 ft-lbs.
Re-check the tightness of all bolts.
Install the transmission mount bolt. Tighten the engine support bolt if necessary to raise the transmission into alignment.. Torque the mount bolt to 50 ft-lbs.
Remove the nut from the engine support, then remove the support.
Reinstall the shift coupler and the speedo cable (for electronic models, pre-twist the cable counter clockwise a few turns).
Reinstall the starter motor. Fit the starter to the studs, fit the cable bracket onto the rear stud, then fit and tighten the rear nut. The best way to install the front bolt is probably to glue or wedge the nut into a socket, then fit extensions and start the nut. I don't know if this will work because I'm not sure the assembly can be lined up straight enough. I just fished the nut down with my left hand, captured it on the end of the stud with a finger and started it with the other fingers. I did it that way twice without dropping it (amazing, as I'm one of the world's best at dropping nuts and bolts in impossible places). You should be able to retrieve the nut with a magnetic wand if you do drop it. Once started, use the proper extension length (10 to 11 inches) and a ratchet to tighten the nut. The torque spec is 35 ft-lbs, but you'll never get a torque wrench in there. Thirty-five ft-lbs isn't all that much, so just tighten it up good and snug. If you disconnected the wires, be advised that there are two places that the solenoid wire could be installed. The correct place on my starter is the connector closest to the front of the engine.
Reconnect the slave cylinder hose.
Reconnect the reverse light switch connector to the switch at the top end of the trans.
Reconnect the ground cable under the bolt at the center end of the trans.
Reconnect the turbo delivery pipe. Pay particular attention to these connections, particularly the one to the intercooler, under the car. I didn't get this one right, and it cause me considerable grief. Make sure it's right and tight.
Reinstall the air cleaner and its housing.
Bend the turbo intake duct upward, then plug the AMM into the turbo intake duct (the AMM connector is on the top, facing aft). Compress the turbo intake duct and angle the AMM into the air cleaner housing. Secure the two clamps.
Install the battery holder
Reconnect the cables to the terminal block and tighten the nuts.
Reinstall the washer fluid reservoir (10 mm bolts at top rear and lower front). Push the washer pump back into the rubber grommet and reconnect the washer hose to the tee/check valve. Refill the washer reservoir.
Reinstall the battery. Connect and tighten the positive battery cable, then the negative battery cable.
Reinstall the wheel liner halves and the fender trim piece. Wish I could help you with this, but you'll just have to struggle it into position. The rear piece is particularly difficult to fit; muscle usually helps. An ice pick or an awl will really help to find the holes where the screws go.
OK, one last check to make sure we didn't screw up anything major. Screwup checklist.
Reinstall the wheels and snug up the bolts. Jack the car, remove the jack stands and lower the car to the ground. Tighten the wheel nuts to 80 ft-lbs and reinstall the center caps.
Bleed the clutch
Go for a test drive. But first, make sue you have some basic tools on board - screwdriver, pliers, basic sockets, wrenches, and the all-important duct tape and baling wire. You're probably tired and you may have missed something. Never go for a test drive after a repair project without basic hand tools on board. This much I have learned from my adventures!
And oh, by the way, since the trans has been out, are you sure there's oil in it? Check before driving.