Replacing Rear Shocks and
 Springs on Your BMW
Wayne R. Dempsey

Difficulty Level: 6
Difficulty scale: Adding air to your tires is level one
Rebuilding a BMW Motor is level ten

[click to enlarge]

     Replacing the rear shocks is easier than the front shocks. The rear shocks are basically a bolt-in replacement. Before you begin, jack up the rear of the car (see Project 1). You don’t need to remove the rear wheels if you’re only replacing the rear shocks.

     To remove the rear shock, place a jack under the rear trailing arm and lift it up slightly. The shocks support the weight of the trailing arm when the car is suspended in air, so you need to remove this tension from the shock prior to removal. With the bottom disconnected, remove the top of the shock and the rear shock mount (see Project 62). Replacement simply involves bolting in the new shock.

     Replacement of the springs is a bit more difficult, and the procedures for the E30 and E36 vary slightly. First, the E30 procedure: Begin by unbolting the bottom of the shock from the trailing arm. Then undo the straps that attach the muffler to the car, along with the front exhaust mounting bracket. You will need the exhaust to be somewhat loose so you can drop down the trailing arms and they won’t get hung up on the muffler pipes.

     Disconnect the sway bar drop links. Then place your floor jack underneath the rear differential and support its weight. Remove the mounting bolt from the rubber differential mount. Inspect this rubber mount and replace it if it’s worn. Also disconnect the speedometer sender connection. Slowly drop the differential a few inches to lower the pivot point for the CV joints and allow you to rotate the trailing arms downward. As you lower the rear suspension, make sure the brake cables and hoses don’t catch on the rear sway bar. With the trailing arms lowered, have a helper push down on them with a shoe so you can remove the springs. Install the new springs and raise the rear suspension back up. Reconnect the sway bar, speed sensor, muffler straps and bracket, and rear shocks.

     The E36 spring replacement is a bit easier. With the rear of the car raised, disconnect the rear shock. Be sure the emergency brake is released (handle down). On the 318is in this set of photos, I had to disconnect the rear sway bar from the trailing arm and the chassis. The bar kept getting caught between the exhaust and the trailing arm, and didn’t allow the arm to drop down enough. Using a 6-foot-long pry bar, pull down the rear trailing arm by putting your weight on the end of the bar. With the trailing arm depressed downward, reach in and pull out the rear spring. I used a long piece of pipe normally used for gas lines since this type of pipe is cheap available at most hardware stores. Don’t try to muscle your way through it without the pipe--it makes the task a whole lot easier. With the new spring in place, reconnect the rear sway bar and rear shock.

     With both the E30 and E36, carefully inspect the rear rubber spring pads. Most of the time they will be perfectly fine, but if they are really old, they may be cracked or worn out. If you encounter tire clearance problems, you can raise up the rear of the car by substituting the upper rear spring pad with a thicker one. Stock E36 thickness is 7.5 millimeters. Replacement spring pads are available in 10 millimeters (part number 33-53-1-136-387) or 5 millimeters (part number 33-53-1-136-385). You can also clip away the center nipple from the pads and combine them for extra height.

     Many people purchase spring kits in order to lower the car from its original height. One word of caution: The stock M3 suspension components are designed to already have the car sit low to the ground. So, if you purchase a spring kit designed to lower an M3 and install it on a stock 3 Series, the car will probably sit higher than you want. If you wish to properly lower your stock 3 Series, use the kits that are specifically designed to lower these cars, as they will compensate for the non-M3 components. Also, if you use a spring set to lower your car, you will have to cut down the rubber bumper stop an amount equal to the amount you’re lowering. Otherwise, you’ll bottom out the shocks against the stop more often.

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