Tech Article Title Author Date
A4 Spring and Shock Installation Rich Letsinger 2000

Introduction

I just completed installation of aftermarket springs and shocks on my 99 A4 Avant. It was quite a job but left me with a great feeling of satisfaction at having done it myself. I probably saved $100 to $200 by doing the job at home. This is the savings of labor minus the tools I had to buy. A couple of the tools are quite specialized, so I didn't have them around. I did have a regular set of hand tools and quite a bit of experience using them. I, however, had no experience working with suspension. The tools I used are:

  • 2 jack stands
  • 2 socket wrenches with short extensions and 13, 16 and 18 mm sockets
  • 6 mm Allen wrench attachment to socket wrench
  • 16 and 18 mm open end wrenches
  • 18 mm deep offset box end wrench
  • 1 pair of spring compressors and a 24 mm box end wrench to turn them
  • rubber mallet and a hole punch
  • protractor
  • I did cut a few corners on this job. I recommend you do not, but I haven't encountered any ill-effects as of yet. I did not use a torque wrench on anything. Without the tightening specs, I just tightened everything about as hard as it was to get off. This is a poor method, but the best I had. I also used all of the original nuts. You're really supposed to use all new nuts because they are the self-locking kind that have a crush ring that holds the threads. Reusing these can allow them to loosen over time. Also, I didn't actually have the deep offset box end wrench. You need this because the bolt has to be held with a 6 mm Allen wrench while you're loosening the nut with the box end wrench. I used a regular socket and grabbed it with vice grips. This barely worked. I suggest you find the right tool. Finally, I didn't use anti-seize compound on anything. It's probably a really good idea to use it.

    If you do go ahead and do this yourself, it's at your own risk. This is the standard disclaimer that I'm not responsible if you hurt yourself or mess up your car following my instructions. I hope that doesn't happen and I've tried to explain things well, but it's a chance your taking.

    Rear Suspension

    I suggest you start with the rear. It's easier and a good way to work into this job. I actually did the rear one weekend and the front the next. The car drove fine in between but was definitely stiffer in the rear and the headlights pointed up in the air. I spent 2.5 hours on each side of the rear.

    1. Jack up the rear of the car and place on jack stands. You'll need to have both rear wheels off the ground to completely free the anti-roll bar. If you don't do this, you'll have to loosen the anti-roll bar to allow the suspension to drop all the way down. Remove the wheels.

    2. Remove the bolt holding the shock to the lower control arm. If the suspension is fully extended on both sides, it should come out easily. I actually compressed the spring while it was still on the car on one side which turned out to not be necessary.

    3. Disconnect the upper control arm. To do this, remove the bolt connecting the two arms that join right above the rear tire. The control arm's bushings are twisted slightly pulling the arm upwards when you release it. On one side, I actually loosened it's mount to the support bearing assembly to make it easier to get the whole assembly out of the wheel well. You'll have to do the next step before you can get a socket wrench on there.

    4. Remove the 4 bolts holding the support bearing assembly and remove the whole shock and spring unit. There are safety tabs or guides for the whole thing. To get it out, push or pry the shock inward at the bottom and the top will pop off the guides. Be careful not to bang anything against the fender lip. I actually put a paint chip right on the fender lip on one side. That's when I loosened the control arm.

    5. Now you can compress the spring. This is the scariest part of the whole deal. My compressors were cheap $25 ones that didn't inspire much confidence. But they worked. I just took my sweet time and tried to keep my fingers as clear as possible.

    6. With the spring compressed enough to take the load off the shock, you can remove the top bolt holding the shock in the support bearing assembly.

    7. Installation of the new spring and shock is exactly the reverse. I installed H&R Sport springs and Bilstien Sport shocks. The shocks have 4 grooves with a c-clip snapped into the bottom one. You can move the clip to another groove to raise the rear ride height. In the lowest groove, the H&R Sport springs dropped my Avant .75 inches from the stock sport suspension.

    8. Compress the new spring and reassemble the shock and spring with the support bearing assembly. Make sure the spring is seated completely in the spring carriers. The end up the spring should be pressed firmly against the stop in the carrier.

    9. Mount the support bearing assembly to the car. Getting this back into the wheel well is almost as hard as getting it out. I had to lower the car onto another jack stand supporting the lower control arm to raise things enough to attach the new assembly. It's a little shorter with new spring and shock. Don't tighten the bolt holding the shock to the lower control arm. The bushing should be centered at normal ride height, so this must be tightened with the car sitting on the ground.

    10. Reconnect the upper control arm.

    11. Reinstall the wheel and set down the car. Now tighten the bolt holding shock to the lower control arm. This is a real paint to get back there with the car sitting on the ground. You'll have to have both sides done before you can tighten these guys.

    Front Suspension

    I went through some real pain for the front. I was missing a part of the Bilstien shock and ended up leaving my car on jack stands for an entire week. Anyway, actual work was about 3.5 hours each side. The additional complexity of the 4-link suspension up front made it harder. Also, there's a angle you have to set for the upper spring perch. It turns out that this is much less critical with the Bilstien shocks than with the stock sport shocks. The body of the Bilstien shock can turn independent of the lower spring perch where on the stock shocks they are fixed together. This'll make more sense once you get things apart.

    1. Jack up the car and put it on jack stands and remove the wheels. Again, getting both sides off the ground is helpful but we have to disconnect the anti-roll bar anyway.

    2. Disconnect the anti-roll bar.

    3. Loosen the three bolts in the engine compartment holding the upper strut assembly. On the passenger side of my 99 I had to remove the plastic rain gutter above the HVAC intake. On the 99.5 + I think there's even more plastic stuff to remove.

    4. Remove the bolt through the top of the wheel bearing housing. This is the joint that holds the upper control arms right at the top of the front tire. With that bolt removed, you can press the upper control arms up and out of the housing. Don't try to spread the housing in the grooves. I used a hole punch and a mallet to pop them up from below. The wheel bearing housing with the brakes attached will be quite loose now. It's a good idea to unclip the ABS sensor wire and support the whole assembly with another jack stand because it can move around a lot. If it moves too far the rubber covers on the ball joints could get pinched and/or torn.

    5. Remove the bolt holding the shock to the lower control arm. This one is a pain. The other lower control arm is the way of pulling the bolt free. I was able to rotate the wheel bearing assembly enough to work the bolt out, but I definitely punch the ball joint boots doing this. The factory manual says to actually extract the ball joint on the other lower control arm but that seem extreme. When I put this back together, I thought about putting the bolt in from the other side, but ended up doing it the same way as the must be some reason.

    6. Now there is an awful little clhip to remove. This is next to the outermost bolt on the under side of the top of the strut mount. It looks like a washer pressed onto a bolt. I pried on the thing with an old screw drive and was able to work it off. Lots of yelling and swearing helps here.

    7. Finally you can remove the three bolts holding the top of the strut and remove the whole assembly. Again, watch the fender lip to avoid chipping the paint. Working the lower part of the shock past the CV boot is a little tough and you don't want to damage that boot.

    8. The top part of the assembly with the control arms attached comes off with two nuts. This exposes the to end of the shock's rod with the nut on the end. This is what you have to hold with the 6 mm Allen wrench while turning the nut with an 18 mm deep offset box wrench. First, you must compress the spring to remove any tension.

    9. With the top nut removed, the whole assembly comes apart. You will need to reuse the spring perch which comes off the shock body with a little hammering. The original bump stop and dust boot are reused as well.

    10. Again, installation is the reverse. The front Bilstiens come with the c-clip in the middle of 5 grooves. I went down one groove which lowered the car one inch from the stock sport suspension. This gave me exactly the same ride height front and back.

    11. Compress the new spring and reassemble the strut assembly. The lower spring perch is not the same all the way around. The back has a flat part with a large hole. The spring sits on rubber holders in both top and bottom perches and must be seated completely. The two bolts in the top spring perch that hold the control arm assembly must be position 11 degrees +/- 2 from the lower spring perch. On the Bilstien shocks, the lower spring perch can twist on the shock body, the the setting really only positions the lower perch. But on the stock shocks, the body of the shock is positioned too which is extremely important to the connection with the lower control arm. I just used a protractor to set the angle approximately. The factory manual actually shows a VAG tool to hold the shock body and set the angle perfectly.

    12. Reinstall the strut assembly on the car. The new parts actually make the whole assembly a bit shorter so it's somewhat easier to work in. Like the rear, I had to lower the car slightly with the hub supported to compress the travel and attach everything. Don't tighten the bolt holding the shock to the lower control arm. Also like the rear, the bushing needs to be centered with the car at normal ride height.

    13. Reconnect the upper control arms to the wheel bearing assembly.

    14. Reconnect the anti-roll bar.

    15. Reinstall the wheel and set down the car. Like on the rear, you must now tighten the shock attachment to the lower control arm with the car sitting on the ground. This one is even a little harder. And again, you'll have to have both sides done before you can do this.

    Congratulations

    You've done it. I hope these instructions helped get the job done and that it was fun. At least thinking back to having done it yourself will be fun.

    The last thing is an alignment. Apparently, few alignment shops can actually do a 4-link AWD car properly. There is a special attachment for the Hunter alignment rack that most places don't have. I'll quote a European Car article by James Sly. Unfortunately, I don't have the date of the issue, but it's a "Tech Procedure" article on an installation done by New Dimensions in San Jose, CA.

    "The B5 chassis has a new and sophisticated front suspension design. The biggest change [when lowering] will be in the toe, which is simple and conventional to set. Unlike previous strut suspensions, there is very little camber change, even when lowering the car. In addition to the normal toe setting, the B5 cars also require a `raised toe setting.' A special fixture is used to raise the car to a specified height, and a separate toe setting on the upper link arm is adjusted to spec. You can't increase or decrease the camber in the manner you could with previous suspensions. The only action you can take with the camber is to adjust it by equalizing it side to side."