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Discussion Starter #1
I have a 1996 Saab 9000 CS that is noticed is sagging in the rear. I have owned the car for the past 50,000 miles and have never changed the shocks and who knows how long it has been before that.
I am wondering if shocks are enough to cause the rear end to sag or is it more likely that the springs need to be replaced? The car passes the "push down on the corner and see if it bounces" test. Bounces once and then settles well enough.
The car is from the north east and I've heard removing the bolt for the shock is going to be a nightmare so I'd rather not replace the shock if I don't need to. I attached some pictures to show the sagging. There are a few things in my trunk and it will raise maybe half an inch if I remove everything.
 

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I think your problem is springs rather than shocks .

Springs deflect (compress) as the vehicle goes over a bump, then bounce back. The truck would continue to bounce up and down if the energy stored in the springs were not dissipated in some way.

The shock absorbers perform this function.

The primary function of the springs is to support the weight of the vehicle,

The primary function of the shocks is to absorb the "shock and rebound" of the vehicle (which is created by the action of the springs).

Without shocks, if you hit a good sized bump, you would continue to bounce up and down for a long time.

On the other hand, without springs, you wouldn't even be able to move - the car would just slam down onto the tires and bottom out.

The thing is; Saab supplied a real nice set of springs as OEM equipment. I have not seen any that have cracked (or that have lost their temper) and allowed the body to settle way down.

And - contrary to what is written above - I have noticed that when old, really played out shocks are replaced with a new stiff set, the rear end definitely sets up higher. So, if the front struts remain unchanged, the whole vehicle develops a slight downward slope (maybe 2 ") that looks kinda cool - like a race car.

I, hope for your sake, it isn't the case that the upper ends of the shocks have broken through their mount points (essentially just the wheel wells). That does happen sometimes in the Northeast.
 

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You may need new shocks all around based on their age, but IMHO you don't need rear springs - you need shorter front springs! ;ol; :cheesy:

Get rid of that front tire/fender gap that all SAABs seem to come from the factory with. Of course, I'm biased because I lower every car I get:

 

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Technically, shocks are dampers. Their only function is to control the speed with which the spring compresses or extends. Their most important and basic function is to confine the frequency of that cycle to close to two compressions and one extension per bump.

However, there are two general types of damper in use: monotube high pressure gas charged and twin tube, usually low pressure gas charged but not necessarily.

Only high pressure gas charged shocks can affect ride height and then only marginally, hardly noticable.

Springs that have not physically failed by breaking generally only lose their spring rate due to extensive corrosion which reduces the effective wire diameter. It is exceptionally rare for a spring to lose its temper and then only one side would likely be affected.

I'd not bother replacing the springs on your car and unless the shocks show clear signs of oil leaking they don't need changing either. Im almost positive SAAB fits Sachs Boge low pressure gas twin tube shocks but I don't know that for sure.

The rear springs on a 9000 are unusually long and rear suspension travel is exceptionally long (I think the range from full compression to full extension is around 8 in. ). Any softening of spring rate will change ride height more noticably with these long springs.

I suspect you may have collapsing spring rubber isolators located in the top spring perch, invisible until you take the spring out. Any noises back there?
 

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Just some general information on the Saab 9000 stock suspension system:





Both front and rear suspensions have helical compression springs.

The springs upper coils are tightly wound, providing a longer spring travel in a limited space.

The springs are fitted with rubber spring cups at both ends that are held in place by the tension of the partially compressed spring.

The maximum extension stop for the spring is incorporated into the damper.
Spring compression is limited by a specially designed stop on the damper piston rod, that provides smooth oscillation damping for the spring, limiting stresses on the attachment points to a minimum.

Specifically for j006:

The 9000 Aero model is equipped with shorter, harder springs, that lower the suspension, thus enhancing the driving performance of the vehicle.

The rear dampers are of the single tube, gas filled type with a double action.

The gas pressure maintains a constant pressure on the damper fluid. This reduces the foaming tendency of the fluid and the formation of air bubbles that can result in noisy damper operation.
 

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Some info on measurements for spring selection as pertains to height adjustment (or maybe vice versa):





The choice of chassis spring is determined by the car height measurement together with the axle weight.

When taking height measurements the following is assumed:

The car should have a full tank of fuel and a full windscreen washer fluid level (normal driving weight).

The car should not have a load apart from its standard equipment.

Standard equipment is a spare wheel, tool kit and warning triangle.

Measure the dimensions "FR" (front suspension) and "RR" (rear suspension) and calculate an average between the two.



The measurement is carried out as follows:

Roll the car forwards and backwards approximately 1 metre to reset the tension in the rubber bushes and springs.

Depress the front and release it.

Measure the height and record the result.

Roll the car forwards and backwards approximately 1 metre to reset the tension in the rubber bushes and springs.

Pull up the front and release it.

Measure the height and record the result.

Calculate an average of the two measurements.

IMPORTANT: If the car is equipped with a tow bar "RR" is decreased by 6 mm.

The following table shows height measurements for model variants. The table permits a tolerance of ±10 mm .

Standard chassis CD ( - M1 992); FR: 592; RR: 577

Sports chassis ( - M1992); FR: 572; RR: 572

Standard chassis (M1992 - 95; FR: 597; RR: 578

Standard chassis CS (M1992 - 95); FR: 606; RR: 578

Sports chassis (M1992 - 95); FR: 603; RR: 590

Sports chassis CS (M1992 - 95); FR: 612; RR: 590

Standard chassis CS (M1995 - ); FR: 595; RR: 577

Sports chassis (M1995 - ); FR: 596; RR: 584
 

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Picture is of a high pressure gas monotube damper. Bilstein makes a good one but so do other damper makers including Sachs.
 

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Discussion Starter #8
Woah! Thanks everyone for all of the info. It has been very helpful.

I honestly don't mind the car riding a little low and the suspension being slightly sloppy. I'm not racing it around a track. It is mostly just freeway driving nowadays.

The main reason I started to address the shock is because I noticed rust right where the shock comes through the wheel well. It hasn't punched through yet so I am hoping to attack it with some rust killer and see if I can at least stop the rust from getting any worse. I tried to remove the shock this past weekend but could not get the upper nut off. The first one came off no problem but the second one will not budge and is starting to round. The part where you grab with the vice grips sheared off and now I'm just stuck with a threaded nub. I didn't have a grinder handy with me at the time but this weekend I will so that will be my next move. (and this is supposed to be easier nut to remove!! I really hope I can avoid removing the whole shock) I'll scrape away all the rust and see how big of a problem I am dealing with.

If it is just too far rusted has anyone had any experience fixing this issue? Can a piece of metal just be welded to the wheel well? Has anybody tried bondo?

I didn't notice any fluid leaking from the shock but I will give it a thorough inspection this weekend. I noticed the carpet hadn't been cut away yet so I take it these are the original shocks. It does making a knocking noise from time to time when going over bumps. Could that be the shock or perhaps the rear sway bar link? Or something else entirely? Thanks again everyone!
 

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Bad news I'm afraid. This particular rust problem can scrap the car. The corrosion you need to deal with is up inside from underneath. By the time it shows up on top of the shock mounting the problem is probably serious. Definitely do not spend money on the car until you get that rust assessed for repair. It is feasible to repair with new metal but not usually cost effective.
 

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If it is just too far rusted has anyone had any experience fixing this issue? Can a piece of metal just be welded to the wheel well?

Not my work pictured in the before & after images below, but it's the way I would do it:







Has anybody tried bondo?

Someone might have but I'm sure it was a waste of time. Bondo has no structural strength.
 

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To better get to the shock tower--instead of cutting the carpet, remove the fasteners around the speaker and rear seat and pull the carpet away uncut. You'll have a much better view of the shock tower area to see and deal with your rust issue. The area is super easy to fix--any competent welder can strengthen this area since it doesn't show, it doesn't have to be pretty which means it can be done cheaply. Bondo will NOT be structural. There are some new adhesives that are structural and could work but for that area welding would probably be cheaper.
Post up some pix of what it looks like.

Chengny--your pix are worth a thousand words!
 

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Rusted shock towers

I had that problem! Much worse than it sounds like you do. The shock mounting point on the top of the wheel well had completely rusted off and I literally had not rear shocks and was bouncing down the road, undamped.

'Cost-effective' is a subjective argument. I took it to a few body shops, who wouldn't touch it (apparently body shops don't do real body work, they just tack on new panels) but then found a welding shop in the woods which was happy to do both sides for $600, including new shocks. They did a very good job.

Now I have rust in 3 out of the 4 fenders.
 

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Discussion Starter #13 (Edited)
I remembered I did take a few pictures last weekend. I did remove the carpet it's just that while removing it I noticed the cutaway section had never been cut. I poked the little spot of rust that you can see in the picture and it just crumbled away so now there is a hole there. I will tackle this some more this weekend and take more pictures.




 

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That's not nearly as bad as I imagined - very reparable. But, you are going to have to give up on your dreams of not removing the shocks. To properly arrest the rusting process, you will need to have access to both sides of the penetration.

If you feel that your shocks are still fully functional they need not be removed from the lower mounts. There is another option - just drop the entire axle.

As you probably already know, in most cases the step that is the biggest hassle of rear shock replacement is releasing the lower mount. The common mounting bolt for the lower end of the shock and the anti-roll bar gets body bound and it is a bear to extract while in the vehicle. It can be stuck in either the sway bar bushing, shock mount or both.



If the bolt is bound, I have given up on trying to get it free and separate everything while working under the car. Last year I had one on my daughters 97 CS that wouldn't release and - after trying everything I could do in that limited space - I resigned myself to going through the hassle of pulling the axle. I had never done a Saab axle before and was not looking forward to learning how.

But, with no other options, I just started doing it. Figuring on any number of seized, rust bound or sheared off bolts and all kinds of rigging and removals - I told my daughter it would probably take me a couple of days. And that was just to pull the axle. Long story short, I was all done and had the axle on the bench within 4 hours.

1. Remove/move aside brake stuff (ABS sensor, e-brake cable & caliper)
2. Torque rods (with brackets) from body. Rods stayed on axle.
3. Anti-sway bar released at upper/inner bushings. Removed bar on bench.
4. Pan hard arm was unbolted at axle end - the PH assembly stayed on car.
5. Placed a jack under the spring link, compressed spring and pulled bolt.

Lowered the axle with a jack - it just balanced nice. Dragged into the shop.

Like this:

 

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I'd spray some rust retardant paint on that, at most, and wait for it to get much, much worse before I touched anything.

The main structural steel is not corroding, just the fender liner. It has some way to go before I'd be getting in there to cut and patch the steel.

The primer used by SAAB is electrophoretic zinc primer. Even if corrosion begins aggressively it spreads very slowly as the zinc in the paint protects the steel.
 

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Tread carefully.
I have a background In restoring Geriatric automobiles for Concours uses. A character flaw happily in remission.. these days.
Years ago realised that 'Rust is Terminal' ..period.
UNLESS one is willing to go to extraordinary ($$$$) efforts. Restoring (as opposed to slapping a patch on) rust out is seriously skilled labor intesive work.
The few capable, do so only with heavy renumeration.. Cuz it's also Ugly working conditions

Sold on my Aero because it had visible telltales of the dreaded shock tower rust.
That rust is only the tip of the iceberg.
Once the towers punch thru.. it's had it.
Just as it was on late 70's 80's BMW's .. a deathbed call to the crusher folks.
Saabs do stave off rust better than most but when it manifests on one.. it's effectively Done
Also wonder at How those rear springs Squashed?
Only Saab springs with failure history were the rears on a C900, even then Saab supplied a spacer ring 'fix'.
Did the Previous owner have a habit of carrying too many bags of Cement ?
 

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Not sure why the nay-sayers wanna scrap your car but I don't agree with that!

(look at my albums here to see what real rust looks like and how easy :roll: it is to treat...)

1) Wire brush the loose rust.
2) Wash and rinse dust & grease off.
3) Treat the area with phosphoric acid like "ospho" http://www.ospho.com/
4) Rinse and let dry or blow dry
5) Coat with a quality paint like "Por-15" or Eastman's.
6) Indulge in the beverage of your choice--you just finished a tedious but very worthwhile task! This area (likely) won't rust in the time you continue using this car.

If you've put 50k on your car you either already know it's worth keeping or it's almost all used up for other reasons (like neglect--it's your car, your business). If it's worth keeping it's worth stopping the rust and replacing the shocks and bushings all around. I now have 232k miles on mine and it's riding pretty nice--more work to do but it's a keeper!
 

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Discussion Starter #18
I am with you guys that say the car isn't worth junking quite yet. I actually finished doing what Banman suggested earlier today before I even saw the post. Luckily most of the rust was just on the fender liner. The shock mount itself still seemed fairly solid.
I scraped away the loose rust, hit it with a wire brush and sandpaper, rinsed it and cleaned it, then coated it with POR 15, then filled the holes with a little bondo, primed it, then painted it with rubber spray paint. Not the prettiest looking job but it should slow down the rust a bit.
I'll keep driving it for as long as I can! My goal is to make it to 215k miles. Anything after that I will consider a bonus. It's my first car and I would hate to see it junked, especially because of some rust. There's still more rust to take care off but the shock was my biggest concern. I'm glad I got it out of the way.





 

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There are now very effective rust killers on the market. The game has changed.

We have effected rust repairs on our two oldest vehicles with good results. The rust has not returned to the windshield header on our 1991 Alfa Romeo 164 more than five years after the repair. Surface rust on the rear fenders has returned but is progressing vey slowly. When deciding whether to repair or junk the car you need to estimate how much extra life you expect out of the car.

Whether it is cost effective is another matter.

Also, rust repair and rust killing has to be done promptly wherever rust attacks structural steel. Before spending any money on rust kill and repair get the condition of the whole bodyshell evaluated by a competent mechanic or bodyman.
 

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Yeah dont scrap the car yet, if you know how to weld or know someone who does it is a cheap fix. Paying someone to fix is where the costs really add up. I had this similar issue on my 9k when i bought it and dropped rear axle and fixed it up in a weekend.
 
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