From digest.v7.n1296 Thu Mar 12 23:28:36 1998
From: Rob Norwalk <norwalk_at_prodigy.net>
Date: Thu, 12 Mar 1998 21:45:18 -0500
Subject: <E36> Rear spring and shock upgrade
Saw some recent inquiries on suspension mod techniques. Here's how I did
the rear H&R/Bilstein sport changeover on my 93 325:
This is fairly straight forward and can be done quite easily alone.
- Remove trunk carpeting (all of it).
You must do this to gain access to the shock tower mounts. In order to
remove the trunck carpet, you'll have to remove the rear speakers (and the
CD player if so equipped).
The speakers are released from inside the passenger compartment. First the
grills pop out by carefully prying up at the _rear_ of the speaker grilles.
The leading edge is a tabbed-hinge under the rear deck material (if you pry
at the front, you may break the grill) After the grilles are removed, there
are two philips screws that hold the speaker cabinet in place. Remove them.
The speaker will stay in place, because of a plastic tab (on the tweeter
side) that slides over the metal speaker cutout and a small metal tension
clip on the inboard edge (woofer side) of the speaker cutout. Push the
tension clip back and press down and the speaker should release. Then go
to the trunk and disconnect the wires, and put the speakers aside.
You will also need to remove the internal tail light covers. The carpeting
will now come out easily. The hard part is over :)
3. Replace Springs - Mark Sipe did a wonderful post on spring replacement
which I'll liberally quote here - Thanks, Mark.
>Jack the rear of the car up enough to get the rear wheels off the ground 2 -
>3 inches and put it on jackstands. Remove the rear wheels from the hubs.
> This may require putting on the e-brake temporarily to break loose the wheel
>studs if you didn't do it before you jacked the wheels up off the ground. If
>you put the e-brake on for this, be sure to release it once you have the
>wheels off! Place the jack under the center of the rear disc brake rotor and
>jack it up until it just touches the bottom of the disc. This is to support
>the suspension when you undo the lower shock mount bolt. It must touch the
>disc rotor itself, not the dustshield, otherwise you'll bend the dustshield!
> Remove the lower shock mount bolt (18mm I think). Once the lower shock bolt
>is removed, lower the jack. When you lower the jack the rear control arms
>should drop slightly. Repeat this procedure on the other side.
>Once you have completed removing the lower shock bolt from both sides, the
>rear suspension should should now be in the unsupported droop position. The
>stock springs will still be slightly tight in their perches. If you look at
>where the upper control arm meets the upper upright spindle mount you will
>notice that the outer half of the upper control arm is boxed in except at the
>outer end, where it is open. You must place a pry bar or small diameter pipe
>(the typical lowbuck floorjack lever handle works great here) into this
>opening to act as a lever arm and help push down on the upper control arm,
>lowering it enough to remove the springs. You may have to put your body
>weight into it, having an extra body to do it while you remove the spring
>would be the easiest way, but I've done it countless times by myself. You
>don't want to push down any more than is necessary to remove the spring.
> More is not better, unless you consider breaking something significant as
>better! The e-brake must be off or you'll never get enough suspension drop
>to remove the spring! Typically the rubber spring isolator pads pull out of
>the perch with the spring. This is the most difficult to do with stock
>springs, lowering springs are usually shorter and will slide in and out
>without having to torque the control arm down as much, depending on the
>When you put the replacement spring in be sure to use the stock rubber spring
>isolator pads between the spring and the perch unless you don't mind your BMW
>creaking like an old trail wagon as it cruises down the road.
>It's easiest to push the upper and
>lower rubber isolator pads onto the spring and install them all at one time.
4. Replace Shocks
If you just did your springs, the bottom of the shock absorber is already
disconnected. If not, disconnect it now. Now put a jack uder the bottom
(free hanging) end of the shock. Remove the two nuts at the top of the
shock tower (in the trunk, you will have to remove a rubber cap first),
lower the jack, and the entire rear shock assembly will come right out.
5. Transfer Hardware
Now you can move the old dust covers and other hardware to the new shock.
This is also an excellent time to replace the upper shock mounts if you car
is at all old. The E30 convertible mounts will fit and are stronger, and
are available for ~$20 a side. Don't forget to transfer the paper gasket
that goes between the shock mount and the shock tower.
6. Put it back together
Installation here really is the reverse of removal, use the jack to hold
the shock assembly in the shock tower will you install the shock tower
nuts. Torque everything to spec. I did everything in under 2 hours by
myself, including springs.
Fort Wayne, IN
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