Friday, March 21, 2014

Installing Bilstein's DampTronic Suspension Kit On Our 981 Cayman

With the 981 Cayman and Boxster still being relatively new, there are scant options as far as replacement suspension kits go, especially for vehicles equipped with Porsche’s PASM system (Porsche Active Suspension Management), which gives the car electronically controlled, continuously adjusting shock damping.


Bilstein answered the call with the recent US release of their PSS line for the 981 Cayman and Boxster in the form of their popular PSS10 and DampTronic (for vehicles with PASM) coilover systems.
As it turns out, the removal of stock suspension and subsequent installation of an aftermarket suspension setup on the 981 is a bit more difficult and time consuming compared to a “traditional” coilover installation process, where you usually have to just take off a few bolts, take out the old suspension, put in the new suspension, and then bolt it all back together.

This write-up is intended to merely be our observations and thoughts of the installation process of Bilstein’s 981 DampTronic system into our 2014 Cayman S, and not a be-all end-all installation guide. We won’t be giving any specific bolt sizes or torque specs, on the off chance that something is different on your vehicle. At the time of this writing, the 981 DampTronic kit did not come with "proper" English installation instructions (it amounted to essentially "installation is opposite of removal"), nor did Bilstein USA have English installation instructions available. Hopefully we can give you enough information to help you successfully installing Bilstein’s into your 981.

Interested in ordering a Bilstein PSS10 or DampTronic kit for your 981? You can order them here, or contact us at 1-888-978-9899 for more information.

So with that said, here’s the usual disclaimer:

This article is being provided for general educational and informational purposes only, and is not intended to be a substitute for any manufacturer’s operation or installation manual.

First thing’s first, get everything out of the box to make sure it’s all there. Asides from the pair of fronts, and pair of rears, your kit should come with a pair of coilover wrenches to adjust the perches with, and 4 bags, each containing a PASM extension cable, bottom cap, and a boatload of zipties. You’ll also get some fairly unhelpful documentation as a bonus (at this time of writing, at least).

As far as tools are concerned, besides the standard array of metric sockets and wrenches that you’ll need, you’ll want to also have the following:

Spring compressors. Even when off the car, the springs on your stock suspension are still under quite a lot of load, and trying to remove the top hat without relieving that pressure will  cause the spring to fly out in one direction, and the shock in the other, with enough force to seriously injure or kill you.
A thin 18mm wrench. One of the bolts securing the collar that holds the bottom of the shock to the control arm on all four corners is in a place where a standard width wrench won’t fit.
If you have PASM and are installing a DampTronic set, you’ll want a modified 21mm deep socket. With the stock PASM suspension, the PASM cable exits from the top of the shock through the center of the bolt that the nut holding the top hat on screws to. Without a modified socket, there’s nowhere for the cable to go, so you can’t take off the nut. The modification needed is fairly simple: just cut out a “window” on the side of the socket large enough for you to pass the cable through without compromising the socket too much.
An impact wrench. While you might be able to get away with the breaker bar/Allen key combination for installing PSS10s, on DampTronic units as mentioned before, the cable passes through the center of the shaft where an Allen key would normally go, so an impact wrench is the only way to remove the nut without causing the shaft to spin.
A wedge of some type. The collars that hold the bottom of the shocks are sometimes clamped a bit on the tight side, even with the bolts removed. Using some leverage to spread the collar a little wider makes removing the stock shock, and inserting the Bilstein shock a much more doable proposition. We used a pickle fork, although you could probably get away with a large, sturdy screwdriver or something similar that won’t gouge the metal.
A small scissor jack. This will help to raise the control arm into position when reinstalling the new suspension.
A method to secure the hub and a place to rest the caliper in the front. We just used some wire and a box to keep the hub and caliper from flopping around.
Someone to help you. While most of this can be done by one person, unless you’re a graduate of Xavier’s School For Gifted Youngsters, having another set of hands to assist you will be greatly welcomed.

A thin 18mm wrench will be a useful tool.
Just to give you an idea as to how thin it is.
For you folks installing DampTronics, you'll need this.
A modified 21mm socket is needed to remove the top nut.
This is the top nut that needs to be removed.
Normally a hex key would fit where the PASM cable now is.
A few quick points ahead of time about setting your ride height with the PSS10s and DampTronics after you’ve completed your install:

The range of visible threads on the shock does not represent the range the perches should operate in. Let’s say that the proper travel range for the spring perches go from 1 to 100. The shock body itself then, would be threaded from say, -50 to 150, as there is an extra amount of threads above and below the proper travel range. Part of this is because Bilstein gives you a few extra threads to work with in case you need it for corner balancing, and the rest is merely a result from the manufacturing process.
The PSS10s and DampTronics have a “minimum height drop”, meaning that even when the perches are set to their highest position (within the proper travel range), you will still be lower than stock height. Trying to set your Bilsteins to stock height means that you will be raising the perches beyond their proper travel range, and compressing the springs (especially the coils on the top) to the point that they will not have enough room to move, which in turn will cause binding at slow speeds, rough ride, and general noisiness.

Once you have your automotive mise en place ready, get the car prepared for removal of the stock suspension. If you have access to a lift, it will help immensely; otherwise, just jack up the end that you’re going to be working on. You’ll want to disconnect the battery as well, lest your dashboard light up with more than half a dozen error codes when you go to turn the car back on (because you’re going to be taking off a lot of stuff, especially in the rear).

We’re starting with the front first, which was a good decision, as the rear turned out to be considerably more of a hassle to do.

Before you get the car jacked up and have the wheels off, you’ll probably want to take some measurements to get a baseline later. Find a place on the fender radius, maybe mark it with some tape, and then measure to the center point of the wheel.

Once you’ve gotten your measurements all around, get the wheels chocked, the car jacked, and get the wheel off. With the wheel out of the way, get a good lay of the land, as you’ll have to disconnect a few sensors and remove several bolts, as well as get a general idea as to how you’ll want to route the new PASM cable (more on that later).

To remove the stock shock (and later have the new ones installed), the control arm will have to drop downwards beyond its normal travel distance so that you’re able to clear the hub from the bolt that it sits on that is attached to the control arm. For that to happen, you’ll have to unbolt the tie rod, the rod linkage for the PASM sensor (if so equipped), and the brake pad wear sensor. You’ll also want to take off the plastic brake ducting to give you more clearance.

Once you have all the components unbolted/disconnected that should be, it’s time to grab your assistant to help you out. Unlike most standard coilover setups where the shock body has a bracket that bolts to the hub, here, the shock body slides into a collar in the hub which is then tightened to hold it in place.

To remove the shock from the collar, you’ll first have to remove the bolt that connects the hub to the control arm. Once it’s removed, you’ll have to pull the control arm downwards so that the hub can clear the bolt (a pickle fork will help), which will allow it to come forward (i.e. if you’re facing the hub, it comes towards you). Once it’s forward and clear of the bolt, the control arm can slowly be let go, and the hub can rest on the edge of it. At this point, you can remove the 2 sets of nuts and bolts that are clamping the collar, as well as loosen the 3 nuts securing the top hat to the strut tower (to give you room to move the shock up and down without it dropping), and slide the shock out (it may take a little finagling to get it free from the collar). With the shock out, put the hub back on the bolt of the control arm, and then secure the hub to the car to prevent it from moving freely and damaging the brake lines or any wires.

Bilstein’s PSS series for the 981 does not come with tophats, as it is intended for you to reuse your stock pieces.

To transfer your stock tophats to your Bilsteins is a fairly simple process. You’ll first want to compress the stock spring to relieve tension. As mentioned in the beginning, if you don’t have a pair of spring compressors, stop what you’re doing and go buy/rent some. Using only a single spring compressor isn’t safe either, as you’ll still have one side putting load on the tophat.

With the stock spring now compressed enough, you can now remove the tophat nut. If your car was not equipped with PASM, you should be able to just use your trusty impact wrench to take the nut off with no issues (or with a breaker bar, appropriately sized Allen key, and good ol’ elbow grease if you’re sans impact). If your car came equipped with PASM, you’re going to have to use the modified socket mentioned earlier to give the PASM cable somewhere to go when you take off the nut. It would also be a good idea to tape up the connector end of the PASM cable, as the impact wrench will make the cable flop around while it takes the nut off, and the force may cause the plastic end to fly off, never to be seen again (maybe).

Before you put the entire top hat assembly onto the Bilstein, it will help to loosen the perch and jam perch to bring the Bilstein spring lower, so that you can place the tophat assembly on top and hand tighten the nut. Once it is hand tightened on, you can then raise the perch and spring up again so that you can seat it properly with the tophat (just match the shape of the spring and where it ends to the bottom of the tophat assembly so that it sits securely).

With everything sitting nicely and lined up properly, you can then tighten the nut using your impact wrench (or whatever you used to take the nut off previously).  Don’t go crazy tightening this up, either. Snug is good, letting the impact gun run until it starts spinning the shaft is bad.

Reinstalling the front is essentially the opposite of removal with only a few points to be aware of. If you’re installing the DampTronic kit, the PASM cable exits from the bottom instead of the top. When you go to slide the shock into the collar, do not have the cable sit inside of the notch on the bottom of the shock; instead, let it hang down free of the shock while you guide the shock body in so that you can ensure the cable does not get pinched. Once the shock body is all the way in, the cable can be slid into the notch (if it’s accessible). Beyond that, just make sure the shock is seated firmly into the collar, tighten up the collar bolts, secure it to the strut tower, and have your assistant once again pull the control arm downwards so that you can put the hub back on the bolt of the control arm, then bolt up the remaining parts and connect all the disconnected plugs.

If you’re installing a DampTronic setup, you’ll also have to run the PASM extension cable. For the fronts, we ziptied the extension cable alongside the black cable that was already going from the hub to the engine compartment area, making sure to give it the same amount of slack, and then connecting it to the stock cable end near the strut tower.

Once you have your extension cable run, and have checked to make sure that it’s not going to bind or snag anywhere, give all your bolts a final check, put the wheel back on, and then do the other side.

Now for the more frustrating of the two ends: the rear suspension.

You might as well go and wash your hands now, because you’re going to have to take out some (or a lot) of your rear interior so that you can access the strut tower bolts, and if you’re installing DampTronics, you’ll be removing essentially all of the interior in the back to get access to the grommet that you’ll be running the extension cable through. For you DampTronic folks, skip ahead to see the picture showing the location of that grommet so you can start taking everything out now, and then come back. We’ll wait.

With the interior removed, you can now begin the task of installing the Bilsteins on the rear. As before, get the opposite end chocked, and get the rear of the car in the air. After taking off the wheel, take a look and see what’s going on.

Unlike the front, you now have to deal with the rear axles, which means you’re going to have to not only disconnect the various sensors and linkages from before, but in order to give the hub room to come forward after clearing the control arm bolt, the axle must be disconnected, either from the axle nut, or from the CV joint. Also, the caliper will have to be detached from the rear hub, as it will be easier to remove and install the rear suspension with the hub completely off the car.

So, get things started by disconnecting the sensors, freeing the black cable from the clip, and removing the bracket by the caliper that holds down the brake line. Once those are disconnected and off, you can then remove the two bolts that attach the caliper to the hub.

With the caliper now free, set it to the side and out of your way, making sure that it can’t be accidentally knocked over, and that the brake line and the brake pad sensor are safe and undamaged.

Now disconnect the two suspension arms attached to the rear hub. We opted to detach them from the ends closer to the center of the car to prevent any possible damage from using a pickle fork. Next to unhook would be the arm that connects to the swaybar. Also, you will have to disconnect the linkage that goes to the PASM sensor. While you might be tempted to just pop it off from the ball end, it would be better to unscrew the nut instead to prevent damage to the socket.

With everything else disconnected, now free the axle from the car from your location of choice (either the 6 small bolts connecting it to the CV joint, or from the large axle nut).

With the axle disconnected, and the strut tower bolts removed, the entire rear hub can then be taken completely off the car to give you more room to work.

There are two bolts that clamp the collar around the shock. On one side of the car, after removing the nuts and bolts, the collar loosened up enough that the shock could be easily slid out (and the Bilstein then slid in). The other side however, required us to wedge the pickle fork into the opening to spread it open a tiny bit more to allow the shock to be slid out (otherwise, it would have gouged and damaged the shock).

The same procedure also applies here: properly compress the spring using compressors, then remove the nut so you can move the old tophat onto the new suspension, etc.


When inserting the shock back into the collar, it is absolutely imperative that the PASM cable not be inserted in the slot on the side of the DampTronic body. Slowly insert the shock while feeding the cable through until the shock is seated all the way, and make sure the cable is completely free and able to move. If the cable is inserted in the slot during installation, the bottom part of the collar will shear it off like a guillotine, as the Bilstein slot doesn’t actually correspond to any opening in the bottom side of the collar.

Once the shock is seated, go ahead and tighten up the bolts on the collar, and then bring the entire assembly back over to the car. Have your assistant guide the axle and control arms into their respective locations while you use your mini jack to raise the hub assembly upwards so that the tophat bolts fit into the strut tower, and then fasten the strut tower bolts in place.

With the strut tower bolts secure, you can now reattach all the arms, and then reattach the brake caliper, as well as reconnect the sensors.

For those of you with PASM, now you’ll have to route the extension cable. Unlike the front, the routing for the rears is less straight forward.  You’ll want to first remove the leading fenderwell lining to expose the grommet that a few other wires are already running through. Then you can follow the black cable that comes from the hub, and branch off from there to pass through the grommet.  Once the cable has gone through the grommet, you can then route it from where it enters into the car, to where the stock PASM connector is located (and now you see why so much of the interior had to be removed just for that one cable).
Once the cable is routed, you can then start putting everything back together. Make sure the bolts are tight, the fenderwell lining is back in place, wheel on.

Now you get to do the other side.

Once all four corners are done, you can bring the car down off the jacks/lift, and see how it sits. Keep in mind that at this point, the suspension has not been put under full load, so the springs have not gone through the cycle of elastic deformation to work out the plastic deformation. Still, just make a mental note as to which corners are sitting higher than the others.

When you reconnect your battery, and start your car, hopefully you will not have any error codes. If you do however, be prepared to have the car trailered to the dealership to have those codes cleared.

If everything seems to be working fine, take the car for a short, slow drive, making sure to make several hard left and right turns while listening for any rubbing or anything out of the ordinary.

Once you feel that the suspension has settled all that it’s going to settle, go ahead and take measurements of the ride height from the same points that you used before the installation, and then figure out how much of a drop you want for the fronts and rears, and adjust the perches as needed. You may need to repeat this process several times to get it where you want it.

With the suspension dialed in, take a step back, admire your newly lowered car, and give yourself a pat on the back for a job well done. And then have fun putting the interior back in.

We actually ended up raising it some after it settled.

Don’t forget to get a four wheel alignment done for your car, even better if your alignment guy does corner balancing as well (after all, your car has the ability to be corner balanced now).

This may seem like a daunting task at first, but as long as you take your time and are careful, you should be able to complete this install with only a minimal amount of swearing.


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