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Audi Rear Springs and Shocks
 
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Pelican Technical Article:

Audi Rear Springs and Shocks

Peter Bodensteiner

Time:

4 hr

Tab:

$100 to $500 per corner, plus alignment

Talent:

*****

Tools:

18 and 19 mm sockets and wrenches, 17mm socket with extension, 17mm wrench, wrenches sized for spring compressor

Applicable Models:

 
Audi A4 (1997-01)
Audi TT (2000-04)
VW Beetle (1999-02)
VW Golf (2000-02)
VW Jetta (2000-02)
VW Passat (1996-00)

Parts Required:

New locking nuts and bolts, new shocks and/or springs

Hot Tip:

Have a shop compress the springs and install the shocks for you to lessen the difficulty of this project

Performance Gain:

New shocks and/or springs can transform the handling of your car and improve its appearance

Complementary Modification:

Rear differential fluid replacement, rear sway bar replacement, rear brake pad replacement

Missing that new-car feel in your high-mileage A4? A new set of shocks can go a long way toward improving your driving experience. Shocks are wear items, and should be replaced periodically.

Because you have to remove the springs in order to change the shocks, we'll cover how to do that too. Springs generally are not wear items--they can break or sag, but for the most part they don't need to be replaced. However, there are other reasons why you might want to change your springs, such as improving the appearance of your car with lowering springs, or improving handling.

If you're installing a coilover package (i.e., a coil and spring combination with adjustable spring perches), you can follow most of the steps shown here, but you may not need a spring compressor to do your installation.

In fact, this job is actually pretty easy aside from the task of removing the spring from the strut assembly. If you'd like to skip most of the hassle of this job and bring the difficulty level down to about a 2, simply remove the whole strut unit, take it to a performance shop along with your new shocks and/or springs, and have them compress and remove the spring and then reassemble the unit with your new components. Most performance shops will have a much more sophisticated spring compressor than the kind you can rent from your local auto parts store. The downsides of doing this are the associated cost and potentially greater downtime for your vehicle.

If you change out the springs, you should definitely have an alignment performed on your car after you're done. Changing the springs--or anything that raises or lowers your car--changes the geometry of the suspension components at ride height (where your alignment is measured), and thus can cause alignment issues that can lead to unusual handling characteristics and uneven tire wear. You shouldn't need to align your car when you change your shocks only, unless the shocks cause a change in ride height, such as if the spring perch on the shock is different than the stock unit.

To start this project, get your car in the air and remove the rear wheels. If you want to compress the springs yourself, you'll need to rent a spring compressor tool (ask for the one for MacPherson strut-style suspensions) at your local auto parts or tool rental store. I rented the compressor for this project at AutoZone for a fully refundable, $50 deposit.

Also, the rear suspension is different on quattro-equipped cars versus FWD A4s, which have more of a beam-axle setup. However, they use MacPherson-style struts as well. In other words, once you unbolt the strut assembly, the rest of the job is similar.

This is the driver's side, rear suspension.
Figure 1

This is the driver's side, rear suspension. Start by unbolting the arm that extends up from the wheel upright (where the wheel hub is) and connects to the upper A-arm. This bolt is a 17mm on both ends and has a locking nut that should be replaced upon reassembly.

Behind the locking nut is a washer that also comes off.
Figure 2

Behind the locking nut is a washer that also comes off. Note the orientation of the washer, which is cupped to the nut side.

Push the bolt through the A-arm and out of the hole in the upright.
Figure 3

Push the bolt through the A-arm and out of the hole in the upright.

Pull the upright away from the A-arm.
Figure 4

Pull the upright away from the A-arm. Note the rubber bushing in the A-arm. Any bolts that go through rubber bushings like this one should not be fully tightened until the car is resting on the ground. This prevents these joints in the suspension from binding, which can cause handling problems.

Looking up into the wheel well, you can see the now-disconnected upright, the A-arm, and the large apparatus that both provides the mount for the A-arm and mounts the strut to the chassis of the car.
Figure 5

Looking up into the wheel well, you can see the now-disconnected upright, the A-arm, and the large apparatus that both provides the mount for the A-arm and mounts the strut to the chassis of the car. Remove the four bolts between the mount and chassis; the A-arm stays in place until you've removed the whole assembly from the car.

A 17mm socket and extension makes it easy to reach and remove the four bolts for this mounting bracket.
Figure 6

A 17mm socket and extension makes it easy to reach and remove the four bolts for this mounting bracket.

With the four bolts removed, the strut assembly can be tilted back and forth.
Figure 7

With the four bolts removed, the strut assembly can be tilted back and forth. The only remaining fastener is at the bottom of the shock absorber.

The lower shock bolt runs through the lower control arm.
Figure 8

The lower shock bolt runs through the lower control arm. This 19mm locking nut should be replaced upon reinstallation.

The bolt head is 19mm as well.
Figure 9

The bolt head is 19mm as well. You'll need to counter-hold this while you remove the nut.

When the nut is off, remove the bolt, and the bottom of the shock is now loose.
Figure 10

When the nut is off, remove the bolt, and the bottom of the shock is now loose.

Tilt the strut assembly outward and use it to push the lower control arm down in order to let the top of the assembly clear the fender lip.
Figure 11

Tilt the strut assembly outward and use it to push the lower control arm down in order to let the top of the assembly clear the fender lip.

In my case I had already removed the rear sway bar, so the control arm and upright easily moved down as I pushed on them.
Figure 12

In my case I had already removed the rear sway bar, so the control arm and upright easily moved down as I pushed on them. However, if you find that yours won't move enough to allow the removal of the strut assembly, you may need to disconnect the sway bar. Remove this 17mm nut and bolt that connects the plastic end link to the suspension upright.

It's a good idea to tape up the fender lip to protect from the strut assembly as you remove it.
Figure 13

It's a good idea to tape up the fender lip to protect from the strut assembly as you remove it. Notice that I did not follow my own advice!

Here is the strut assembly removed from the car.
Figure 14

Here is the strut assembly removed from the car. The upper A-arm is still attached. You may not need to remove it in order remove the spring and shock, but I'll show how to do it just in case.

Strangely, the nut on the upper control arm bolt is 18mm, while the bolt has a 19mm head.
Figure 15

Strangely, the nut on the upper control arm bolt is 18mm, while the bolt has a 19mm head.

That's one long bolt! The nut is another one that should be replaced during reassembly.
Figure 16

That's one long bolt! The nut is another one that should be replaced during reassembly.

The A-arm is free to be removed.
Figure 17

The A-arm is free to be removed.

Time to apply the spring compressors.
Figure 18

Time to apply the spring compressors. These were rented tools and are similar to others I've used in the past. They consist of two hooks with a threaded rod running through them. The hooks get closer as you turn the threaded rod, thus compressing the spring. Install the two compressors on opposite sides of the spring, and attach the hooks to spring coils as close as possible to the ends of the spring.

I was unable to get the two spring compressors directly across from each other, which would be ideal.
Figure 19

I was unable to get the two spring compressors directly across from each other, which would be ideal. The threaded rods have to be positioned just so to avoid contacting the large upper strut mount, and the narrow gaps between the coils of the rear springs make it more difficult to find places to insert the hooks. I just got them as close as I could and then compressed the spring carefully to avoid kinking it or bending it to the side. Remember that there is a lot of energy stored in those springs as you compress them, so tighten the spring compressors carefully and take heed of anything unusual that you see or hear.

This is your goal
Figure 20

This is your goal--compress the spring enough that the last coil starts to come off of its seat.

Here's the other end of the spring as it lifts off of its perch.
Figure 21

Here's the other end of the spring as it lifts off of its perch.

With the spring compressed, you should be able to easily remove the bolt that secures the upper end of the shock absorber within the mounting assembly.
Figure 22

With the spring compressed, you should be able to easily remove the bolt that secures the upper end of the shock absorber within the mounting assembly. Converse to the upper control arm bolt, this one has a 19mm nut and 18mm bolt head. The nut is another one that should not be reused.

This is an exploded view of what you'll see as you slide the shock out from the mounting assembly.
Figure 23

This is an exploded view of what you'll see as you slide the shock out from the mounting assembly.

Here's the new Bilstein shock side-by-side with the stock shock and spring.
Figure 24

Here's the new Bilstein shock side-by-side with the stock shock and spring. Note that there are not any parts that need to be removed from the old shock and installed on the new shock.

The rear shocks are small in diameter, and the shocks have many protrusions and other obstacles.
Figure 25

The rear shocks are small in diameter, and the shocks have many protrusions and other obstacles. With these particular spring compressors in place, the shocks could not be removed. So, I had to decompress the spring, swap in the new shock, and compress the spring again. Fun!

Take note of how the stock spring rests upon the lower spring perch that comes with the new Bilstein shock.
Figure 26

Take note of how the stock spring rests upon the lower spring perch that comes with the new Bilstein shock.

Clearance to the Bilstein shock is tight at some points too.
Figure 27

Clearance to the Bilstein shock is tight at some points too. Take care to clear these as you compress the spring again to prepare it for installation.

Put the upper mount in place to test the fit of the top of the spring
Figure 28

Put the upper mount in place to test the fit of the top of the spring--it must rest properly in the spring seat. Note the tight clearance again to the threaded rods of the spring compressors. You will need to arrange the two compressors so that you can both seat the spring properly and clear the spring mount while you compress the spring.

Once you have the compressors where you need them, you can start compressing the spring.
Figure 29

Once you have the compressors where you need them, you can start compressing the spring.

From time to time, fit the upper spring mount to the top of the spring so that you can check your progress.
Figure 30

From time to time, fit the upper spring mount to the top of the spring so that you can check your progress. You need to line up the upper shock mount with this hole in the mount.

31
Figure 31

Once you get to this point, you should be able to push down to compress the spring just that little bit more...

... and push the bolt through to secure the upper shock mount.
Figure 32

...and push the bolt through to secure the upper shock mount. You should use a new bolt for this.

Secure the bolt with a new self-locking nut and tighten it to 52 ft lb, plus 1/4 turn.
Figure 33

Secure the bolt with a new self-locking nut and tighten it to 52 ft lb, plus 1/4 turn. Then slowly loosen the spring compressors, making sure the springs seat properly as you go. Once the compressors are off, the assembly is ready to go back on the car. As you reassemble the rear suspension, don't tighten the nuts and bolts down fully. These fasteners should only be tightened to their final specs with the suspension at its final ride height. You can achieve this by raising the suspension with a floor jack--it will be much easier to reach the fasteners this way than if you wait until you actually install the wheel and lower the car back to the ground. Reinstall the upper control arm with a new nut and bolt (37 ft lb plus 1/4 turn--but not yet!) and put the whole assembly back into the wheel well, taking care not to contact the fender lip. Use a new bolt and nut to attach the lower shock mount (52 ft lb plus 1/4 turn--again, not yet!). Also use a new bolt, washer, and nut to attach the end of the A-arm to the upright (37 ft lb plus 1/4 turn--not yet!). Then raise the strut assembly up to mount it to the body. Tighten the four mounting bolts to 41 ft-lb (you can do these now).

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Comments and Suggestions:
93 mustang then audi tt now Comments: After installing new struts and hardware rubber parts, the upper cone washer/bushing has a large gap at the body. The mounting nut is tight against the strut bushing nut. Yes it is on the tires. Settle with miles?
August 10, 2013
  Followup from the Pelican Staff: This is normal. If you jack up the car you will see it drop. This is because of the flexibility of the upper strut mount. - Kerry at Pelican Parts  

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