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Old 03-26-2020, 03:19 PM   #1
J-roc
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Default 700 900 Series Short Strut DIY



I've gotten a ton of questions over the past few years on how I made the short strut coilovers for my 740 so I figured I would create a thread on how to do this yourself. This should save you a bit of money over buying prefabricated units. Would like to thank Robbie Barber and Asher Carson-Miller though for helping fabricate these and providing information.

Front Struts:
To start out you're going to want to track down a pair of Saab 900 front struts, these will be a 1994-1998 range. For mine I used KYB units but I'm sure other units would work just fine here as well.
These shocks are several inches shorter than your stock units and just about the right diameter. A few modifications will need to be done to these but we will get to that later.

Next you'll need to track down springs, adjusters, weld rings for the tubes and upper spring perches.
- The weld rings you could find a piece of steel that is the right ID for your strut tube or do what I did and purchase them from Ben Kaplan as you'll also need another piece at least from him
- Upper spring seats/ perches I would definitely get from Kaplan as they adapt the stock bearings to work with the 2.5 inch ID springs needed here. An experienced fabricator could also make something for you here but this saves you a headache.
- Springs, you can play around with this a bit depending on what you want to use. Fronts are a 2.5 inch ID spring. Weights and lengths will vary depending on preference. I actually have two different front springs that I will alternate depending on the ride height i'm going for. I run an 8 inch 250lb spring to get the look above, and a 10 inch 300lb spring for when I raise the car up for winter and put snow tires on my car. Even then with a set of nice 17's and appropriate tires this would still look nice.



- Adjusters. You can again get these from Ben Kaplan or there are several universal sleeves and adjusters you can get on places like Summit racing. Take measurements beforehand of the OD of your strut tube to ensure a good fit. What you'll find here is most sleeves will be slightly loose on the tubes. To take up that slight gap you can paint your strut tubes and while the paint is still wet slide the sleeves over it. This is really just to avoid any frustration when unloading/ disassembling the suspension in the future as when the suspension is loaded and these are pressed against the weld sleeves these will not move.



One last thing to get which is very important is sleeves for your strut mounts. The Saab struts have a slightly smaller OD than the stock front struts and you'll need to take up that space with something. Stock 7/900 struts have an 18mm diameter whereas a Saab has a 16mm.



As you can see if you left these without the strut would shift around in the mount and cause all sorts of issues. What you'll want here is a bearing sleeve with an ID of 16mm and and OD of 18mm. I purchased mine from Mcmaster Carr but i'm sure you could find these elsewhere. To save you some research though the Mcmaster part number is 6679K19 and are a little over $3 per.



Here you can see the bearing sleeves fitted on the strut. They don't go all the way up the non threaded length but this won't matter as the strut won't be able to shift around. If you really want to be technical you could always order a second set and trim them so you get that full length.

Next we start cutting. You'll need to hack off your stock spring perches and grind them smooth to the strut tubes. I don't think I need photos here as this is pretty self explanatory.

The next steps I would reach out to a local fabricator unless you have a band saw or a welder. Cut your strut tubes midway down. For mine i did them slightly below where i previously had my standard coilovers set up. If you're going from a stock setup to this ensure you're not cutting in a space where your adjuster sleeve or weld ring is going to lie. As you can see in the below photo the Saab strut is significantly shorter than the stock Bilstein unit lying next to it.



Once you cut the tubes you'll find that the Saab struts don't quite fit in the tubes most likely. Different shock brands will vary here But most likely you're going to need to do some sanding. Ensure the strut tubes are clear of any debris as well as this will prevent these from fitting. Once you've sanded the shocks down and verified they fit in the tubes you'll need to do some math and figure out how much material to remove. Since these have gland nuts you'll have a bit of wiggle room to play with. Just ensure you leave a small amount of the shock protruding from the tube so the nut will tighten down.

NOTE: The gland nuts that come with the Saab struts are a different thread pitch than Volvo so you will not want to use these. I would recommend reusing your stock ones. My Bilstein TC units worked great here. I know the factory Sachs gland nuts have a smaller opening for the shock valve which may interfere with these so make sure everything clears or you may have to widen out the inner hole on the gland nut.

Once you've done your cutting you'll need to weld the strut back up. I would recommend putting the assembly together and then tacking it and then removing the shock and then completing the welds, ensuring that there isn't too much weld penetration as you'll end up with a shock that won't fit in the body again. Mine we ended up rolling the dice by keeping the shock in the tube the whole time. Who knows if it'll actually come out down the road. That's a future me problem though.
Note: The shock bodies are galvanized so you'll want to sand the outsides slightly prior to welding.



After that you'll want to also weld on your lower spring adjuster sleeve weld ring if you haven't already. You'll end up with something like this.



After that go ahead and paint your strut tubes to prevent rust from forming and to make everything nice and pretty. I used a metallic black Rustoleum which has held up great over the few years I've been running this setup. Then assemble your struts and you'll see something like this:



These will then just bolt in. Nothing crazy here. I will say, start at the top of the adjusters. I run my car at the top of the sleeves on my 8 inch springs and it looks like this:




Rears:
With rear shocks and adjusters this is a lot simpler as there are less components that need to be dealt with. I will note though that you should definitely have an adjustable panhard and torque rods for the car as the axle will try to shift and deflect a lot when lowered this far.

Adjusters you can buy from either Ben Kaplan if you're looking for a bolt in solution with no hassle or find a universal 5 inch diameter spring adjuster set up. The only thing special you'll need is an adjuster sleeve with one closed end and a hole through the center where you can mount it to the body of the car.

Springs you can find from a variety of sources but they'll need to be a 5 inch diameter spring so they fit into the the lower perch/ trailing arm. I'd recommend using Blue Coil spring/ Suspension spring specialists as you can purchase whatever weight and length you want. I would pick something like an 8 or a 10 inch rear spring here with a lighter weight than you're running up front as there is a lot less weight in the back of these. For example I am running an 8 inch 200 lb spring.

Shocks. This is where things go back to fabricating a little bit. If you've lowered the back of the car like you did the front the back of your car will now ride like hell. The stock shocks will be bottoming in the tubes and you won't have any travel left. To remedy this I purchased a set of shocks for a Chevy S10/ Blazer, GMC Jimmy etc... these things fit a ton of cars. I would opt for the Bilstein HD units which are part number 24-014120 as they have removable shock end bushings. Some brands will have vulcanized end bushings. IE- KYB

So you'll then want to punch out the bushings on these shocks and press in the 7/900 series units. You'll either get these from your old shocks (Bilstein units you can transfer over) or you'll want to purchase some eyelet bushings on someplace like Summit racing. They offer replacement shock bushings in a hourglass shape which is what these will be. Then just push in your stock sleeves.







Once you press the bushings in these will bolt in as usual but be a shorter length so you'll actually have some shock travel again!

Let me know if you have any questions, input or if I forgot any details.

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Old 03-26-2020, 03:25 PM   #2
Mark G
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About half of the pictures aren't working. Pictures 1-6, 10, & 12 show up as an error graphic.
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Old 03-26-2020, 08:54 PM   #3
blkaplan
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Might want to tell people where they can get them beyond my name.

This link has most of the stuff you would need to DIY

https://www.bneshop.com/collections/...mponents-parts
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