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9-5 Arc Rear Suspension Upgrade

8K views 51 replies 13 participants last post by  EdT 
#1 ·
I'm looking to upgrade the rear suspension on my 2004 9-5 Arc wagon. The old suspension is sagging quite a bit, and I'm about to install a tow hitch and start towing small trailers. I'm worried that with the extra weight of a trailer, or even with a bit more time, the suspension will sag to the point that the tires will start to rub against the wells. So what I'm looking to do is to replace the springs and shocks, but I'm not sure exactly what to get. I was looking at some lesjofors springs and possibly some bilstein shocks and I found this page on esaabparts that lists possible replacement components. I don't know a whole lot about what I'm looking for, so hopefully you guys can help me figure it out. Thanks in advance, ~Bishop
 
#2 ·
Get the police springs. If I didn't have an Aero wagon, I'd buy those in a heartbeat. Bilstein shocks are highly regarded around these parts, but I'm perfectly happy with the stock Sachs. One of my cars got 200,000 miles out of the originals, and the other had 150,000 when I replaced them.
 
#7 ·
i am also looking at replacing the shocks on my 2004 linear, (relatively low miles at 120.000 km) and want to add a towbar soon after and be able to use a trailer at the higher weight limit of what is allowed (with trailer brakes)
would the bilstein B4 (front and rear) and police springs on the rear be a good choice to fit this purpose ?

on my old 900 i had shocks on the rear that could be adjusted with an air compressor to adjust the ride height of the rear suspension when when the car was under heavy load (the original owner used to transport heavy photographic equipment sometimes). is that more what i should look at ?
 
#3 ·
I hadn't even considered the police springs, so alright I can do that. And my car is at about 163,000 miles so it probably won't hurt to replace the shocks too. Do I need a particular shock for these springs or will the bilstein b4 OE quality ones work? Also, is there any other differences in the suspension for the police chassis that might cause a problem?
 
#4 ·
FCPEuro had the OE sachs shocks (supposedly equivalent to the Bilstein B4 in ride quality) on sale for $49 each thru last week. I picked up two. Not sure if there are more still. I'll be replacing those and with some spacers to bring back ride height.

@Jeremy R. do you know if the police springs are progressive, or are they heavy-duty through the entire compression?
 
#5 ·
Saab original police springs and self leveling shocks are extremely rare. Saab (actually SDCC) installed those +35mm springs to Swedish police and emergency 9-5 wagons. Swedish police cars have 3 police radio systems and no original radio.
 
#6 ·
Maybe the HD springs would work okay. I put in standard replacement wagon springs, all the rear bushings were done, and the shocks are Bilstein B6. Rear doesn't really sag while pulling a trailer loaded to the "no brakes" weight of 1000 lbs.

Depending on the brake setup your Arc has, you may want to ensure you have the 302mm front and vented rear rotors if they're not on the car already. The 9-5 wagon is a heavy beast already.
 
#12 ·
Depending on the brake setup your Arc has, you may want to ensure you have the 302mm front and vented rear rotors if they're not on the car already. The 9-5 wagon is a heavy beast already.
If you're planning to tow a heavy trailer with brakes, the HD springs might make sense. Your ride when unladen will be pretty stiff and crashy over cracks and bumps.

Upgrading front brakes to 308mm and rear brakes to vented spec is advisable.
I'm not sure exactly what I'll be towing in the future. I'd like to get a small camper at some point, so it would be nice to be ready for that. And my Saab is a 2004 and it should have 304mm front rotors and 300mm rear vented rotors, according to this forum post and looking at my own car.

What is your ride height? It should be 610mm from the bottom of thealuminum wheel to the lower part of the wheel well and measure through the center of the wheel.
610mm is about 24 inches, yeah? Well, I went out and measured from the bottom of the wheel, not the tire, and it measured about 21 inches or about 533mm to the wheel well.
 
#8 ·
I'm looking to upgrade the rear suspension on my 2004 9-5 Arc wagon. The old suspension is sagging quite a bit, and I'm about to install a tow hitch and start towing small trailers.
i did a fair bit of searching on saab forums about shocks replacement options for worn original sachs OE . my criteria for new shocks were for general confort on mixed road surfaces (including country roads in australia), better general handeling in city and freeway, but not for "sports" performance type driving), and looked at different prices from the different usa and european suppliers.
my general conclusion was
  • both bilstein B4 and koni special active (their base model) rate well by saab users and on other reviews. the koni's tend to get better reviews on quality of build and longer lasting. they are similar in price in some countries, if a significant price difference that might sway the decision to the bilstein B4's (which i will probably do)
  • for those happy with sachs brand, it is possible for the linear or ARC to use the aero schs springs (front and back) which are better then the standard sachs
i hadnt looked at spring options yet, and am also still looking for information on rear suspension and the use of trailers ...
 
#9 ·
The B6 are stiff, I can tell you that.

If you're planning to tow a heavy trailer with brakes, the HD springs might make sense. Your ride when unladen will be pretty stiff and crashy over cracks and bumps.

Upgrading front brakes to 308mm and rear brakes to vented spec is advisable.
 
#10 ·
A 9-5 is good for about 2000 pound maximum towing capacity according to the owner's manual, obviously done correctly the 9-5 is capable of towing more than that but to each their own.

The reason I bring this up is you guys are discussing towing and springs and shocks...the correct tongue weight should be 10 to 15 percent of whatever you are towing, so if you are following the manual the correct tongue weight for maximum load would be 200 pounds.
273582

I tow my 3400 pound boat (only short distances, boat ramp right next door and yes she can pull the boat out no problem) the tongue weight of my set up is about 200 pounds (not correct for highway use but makes it easier to tow with my lawn tractor) and the car doesn't squat all that much, maybe an inch or two depending on how much gas is in the bow tank when I hook it up,

Are the wagon springs that wimpy?

Is it because they take on more weight over the course of their life?

Bored inquiry, not much else.
 
#11 ·
What is your ride height? It should be 610mm from the bottom of thealuminum wheel to the lower part of the wheel well and measure through the center of the wheel.

New springs are probably a waste of money. Your Saab springs are sacked and this a permanent condition. HUNDREDS of Saab 9-5 owners have installed spring spacers for $49.95 a pair. look here and on other forums for hundreds of saab rear suspension posts.

I also like the Bilstein B6 shocks. They are great and a great value.

The new springs will sag too.....even if they are "police" springs.....I am assuming these are stiffer......I have never seen anything called Saab police springs.
 
#13 ·
According to Saab North America, a 9-5 can tow a 1000 lb trailer without brakes, a 3500 lb trailer with brakes. Maximum towing speed for the braked trailer is 60 MPH. No speed restrictions noted on the 1000 lb unbraked trailer. There are notes on tongue weight as well.

Saying that all Saab springs sag is an overgeneralization.
 
#14 ·
Saying that all Saab springs sag is an overgeneralization.
Has anybody ever seen a 9-5 whose rear ride height hasn't drooped, though? Perhaps springs aren't 100% of the issue, but I literally just replaced the forward trailing arm bushing, and all 4 rose bushes, and, while that tightened up the handling quite a bit and brought the , after settling in, the ride height only came up a few millimeters. That leaves either the inner lateral arm bushes or the springs as the culprit in at least my case.
 
#19 ·
The IG3Tech spacers come with installation instructions that includes a PDF and tables. Rear ride height for 17" wheels and non-sport suspension is listed at 620 in order to achieve the nominal camber of -0.8 degrees.

When I have measured with a tape measure, I hooked the tape over the rim bead and stretched it up. I did not use a plumb bob, i.e., the measurement was not taken in the vertical axis.
 
#20 ·
Good information cleeland, Here is some more from the IG3 tech installation sheet


It is important to measure both sides. Usually you will find a different measurement side to side. The driver’s side is probably lower than the passenger side. Take this measurement a couple of times. Roll the car back and forth as in the instructions push up and down on the rear suspension and measure again. Average all your measurements to get a good number.



WHEELS15” inch16”17”17” AERO
FRONT600mm610mm630mm620mm
REAR590mm605mm620mm610mm

Write these measurements down.

For example the 95 Aero ride height is 610 at the rear. Let’s say measure and you find 575 on the driver and 600 on the passenger side. You will need 3 of our red thin spacers on the passenger side, and one of the aluminum ones and 4 of the red ones on the driver side.
 
#21 ·
For me, the factory ride quality is about perfect on my 2006, and I didn't want to use a different shock. I really like the Sachs OEM shocks, so I stuck with those and just added spacers to correct the sag. I probably slightly favor cushy ride quality over performance, so take it with a grain of salt.
 
#24 ·
There is no inner part of the rim available on all rims. Therefore I assume one should use the outside part of the rim to be independent from the used rim.
Pure speculation: the difference of 10mm in Saab original recommendation is due to difference of front and rear plastic inner fender. (when you use the plastic fender instead of the metall part).
In the end no one knows exactly what they had in mind and what is the correct measurement method.
 
#25 ·
There is no inner part of the rim available on all rims. Therefore I assume one should use the outside part of the rim to be independent from the used rim.
Pure speculation: the difference of 10mm in Saab original recommendation is due to difference of front and rear plastic inner fender. (when you use the plastic fender instead of the metall part).
In the end no one knows exactly what they had in mind and what is the correct measurement method.
you measure to the metal part.....that is just common sense.

Why make it so compicated?

Spring sag and need help probably spacers are best choice. At least they are cost effective and are the right way to do it.
 
#30 ·
while doing up grade check rear chamber. Factory supplied unadjustable control arms may need to be replaced by aftermarket adjustable control arms available online from eEurosports.com. I did a lot of heavy towing but only a total ofabout 6 times in 3 years but constant 500lb tool load in a '99 9-5 wagon and it was sagginging to the point of tire rub on wheel well at the lower front interior side point on one wheel. bad chamber was also creating severe wear on inner edge of rear tire treads. had too many other major issues in a 5 year period even with low mileage 53k to 125k to ever do the investment in a rear suspension rebuild and then the car got totaled this past winter
 
#32 ·
I think you are talking about camber. Toe in is even more destructive to tires than negative camber. Ride height is the critical measurement and before you put those adjustable control arms on there you need to mesure ride height and correct it. Springs sag. Negative camber increases. Toe-in increases. Raise that car to the right height with spacers and have a 4 wheel adjustment done......I know you don't have the Saab anymore, but this is the right proceedure.
 
#36 ·
The entire rear suspension setup on these cars is weak. The springs sag and the bushings all fail far too soon. The Saturn L and LS wagons shared the same chassis and rear suspension design, and have the same issues. The adjustable rear control arms were designed for the Saturn wagon, but just happen to fit on ours.

This site is full of information on the rear suspension, including a picture of a 9-5 rear spring that's far too compressed while sitting still:

 
#38 ·
The entire rear suspension setup on these cars is weak. The springs sag and the bushings all fail far too soon. The Saturn L and LS wagons shared the same chassis and rear suspension design, and have the same issues. The adjustable rear control arms were designed for the Saturn wagon, but just happen to fit on ours.

This site is full of information on the rear suspension, including a picture of a 9-5 rear spring that's far too compressed while sitting still:

I have to disagree. This is a well designed 3 link rear suspension that does a terrific job of keeping as much tire contact to the road as possible during cornering. It is a contemporary design with excellent geometry. Have you studied and compared this sytem to other designs? Would you like the old beam from the 9000 or 900 back again......now that is CRUDE!

The site you lead us to is full of half truths and has been around for a long time and really tells us nothing.

We are now talking about cars with 100,000 to over 200,000 miles on them. Rubber bushings ALL cars fail.

I will say that Saab springs do sag, but that is easily fixed with spacers and a proper alignment.
 
#37 · (Edited)
I got the my Sachs rear shocks installed last night with spacers from IG3Tech (pics below). Holy cow were the old shocks tired. The difference in response btw old and new just to my body weight (which isn't all that much, relatively speaking) was noticeable. I did not measure the uncompressed springs because I was in a race against dwindling daylight.

273730
273731


Still not driven; had issues torquing the lower shock bolt to 140 ft-lb. While it's up and driving it isn't necessary I have a few more things to knock out on the list:
  1. Install new-to-me hitch (garage rescue from another local saab enthusiast)
  2. Brake fluid flush
 
#45 ·
Hope you dont mind me butting in. I have a 2006 9-5 Aero Wagon and - it sags on the rear. Its now on its third set of dampers. B6s failed after less than 40,000 miles. Konis lasted about 40,000. Had to fit a temporary set- and am seriously considering using the Police version. Having studied EPC carefully I'm frankly not sure which damper+spring kit to use. I believe the part number is 32025656 for the full damper/spring set for the rear. Would anybody here able to help confirm or point me to the right part numbers?
 
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