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Pelican Technical Article:

BMW Technical Article

BMW E36 3 Series Rear Suspension Overhaul
Jared Fenton
Wayne R. Dempsey

Difficulty Level: 5
Difficulty scale: Adding air to your tires is level one
Rebuilding a BMW Motor is level ten

     In this tech article, we will discuss replacement of the rear shocks and springs on the BMW E36 3 Series.  This article applies to the rear suspension on all 318, 325, 328, and M3 models from 1992-99, except for the 318ti which uses the rear suspension setup off the earlier E30 models. Please check out my tech article on replacing the rear suspension on the E30 if you have a 318ti.

     The first step in overhauling the rear suspension is to loosen the lugs on the rear wheels while the vehicle is on the ground, but do not remove them. Just get them loose and then snug them back up. Next jack up the rear of the car.

     Once the vehicle is firmly supported by jack stands, remove the lugs and take the wheels off. You will now see the shock/spring assembly. First, we will remove the shock absorbers, and then remove the coil springs. To remove the shock absorbers, first place a jack or jack stand under the rear trailing arms. This will prevent the trailing arm from crashing down to the floor when you remove the shock absorbers. Be careful not to place the jack stand on any brake, or electrical connections. Also be sure to place it in a way that it wonít slip off.

     Next, get inside the car and remove the rear speakers. This will give you the clearance needed to access the upper shock mounts. Once the speakers are out, remove the inner trunk liners. They are held in by a series of small plastic clips. Simply pry them out and remove the liners.

     Now look at the upper shock mounts. They are held in place by two 13mm nuts. Remove these nuts and place them in a safe place. Now, get back under the car and while holding the shock, remove the lower shock mounting bolt. The shock absorber will now be free of the car, just slide it down to clear the shock perch. Just repeat on the other side.

     With the shocks removed, we now can remove the coil springs. To do this, keep the jack or jack stand under the trailing arm to keep it from crashing down. Next, we will need to remove the driveshafts from the differential. We have to do this in order to provide enough clearance for the trailing arms to rotate downward and allow the coil spring to come out.

     Itís a good idea to spray the bolts securing the driveshafts to the differential with a good penetrant spray about a day before removing them. Iíve found that 3 in 1 oil works best on driveshaft bolts. Let it soak in for about a day, then use a Torx socket to remove the 6 bolts on either side. Use a zip-tie or rope to secure the driveshafts and keep them from hitting the floor.

     Now slowly lower the jack stands on either side of the car. This will case the trailing arm to rotate downward. When they are lowered far enough you should be able to reach in and pull the spring out of the car. You may find it necessary to have a helper stand on the trailing arm to get it to rotate fully down. Place the new springs in place of the old ones, making sure to rotate the spring so it lines up with the grooves in both the top and bottom of the retaining pads.

     Jack the trailing arms back up on either side and re-attach the driveshafts to the differential. Itís a good idea to put a little bit of Loctite on the threads to keep them from working out. To apply Loctite, you must clean all the grease and grime off the bolts, and then wipe a small dab on one side of the threads.

     Believe me, you donít want a driveshaft coming loose. I forgot to put Loctite on the bolts in my old Porsche 914, and they worked loose, eventually causing the bolts to shear off. The driveshaft was thrown upward, ripped off the starter motor, and put a 9 inch crack in the side of the transmission. Lots of money to fix that one.

     I should take this time to point out that certain cars had different size driveshaft bolts. It will be either 8 or 10mm Torx. If you have the 8mm bolts, torque them to 47 ft/lbs. With the 10mm bolts, torque to 62 ft/lbs. 

     With the new coils installed, we now can install the new shocks. First, take the new shock mounts and slide them over the shaft on the new shocks. Next place the shocks in a vise and install the new self-locking nut that secures the mount to the shock. You will want to transfer the washer on the old mount to the new mounts. Tighten this nut to 10 ft/lbs. Next, have a helper get under the car and slide the shock/mount up through the shock perch. Make sure that the gasket is in place between the body and the mount. With the helper holding the shock in place, install two new 13mm nuts to hold the mount in place. Torque these nuts to 17 ft/lbs.

     Now that the upper mount is in place, go back under the car and using a jack, raise or lower the trailing arm assembly until the lower shock mounting hole lines up with the threads in the trailing arm. Once lined up, install the lower shock mount bolt, and torque to 57 ft/lbs.

     This done, remove the jack or jack stands from under the trailing arms and re-install the wheels. Be sure to snug up the lug bolts. Now lower the car and torque the lug bolts in a criss-cross pattern.     

     Well, there you have it - it's really not too difficult at all.  If you would like to see more technical articles like this one, please continue to support Pelican Parts with all your parts needs.  If you like what you see here, then please visit our online BMW catalog and help support the collection and creating of new and informative technical articles like this one.  Your continued support directly affects the expansion and existence of this site and technical articles like this one.  As always, if you have any questions or comments about this helpful article, please drop us a line.

Comments and Suggestions:
Veteran Comments: how long can a coil spring last before change. Mine has never been changed. BMW # series 318
April 1, 2013
  Followup from the Pelican Staff: Coil springs last quite a while. A lot of depends on climate and use. Measuring your ride height is good way to see if the springs are sagging. - Nick at Pelican Parts  
Matt Comments: Also, at least on my e36 m3 with the Harmon Kardon stereo, I did not need to remove the rear speakers at all. I had plenty of clearance to mount my TC Kline upper mounts, it just takes a little finesse to slide the trunk carpet back up behind them.
August 28, 2012
  Followup from the Pelican Staff: Thanks for the tip- Nick at Pelican Parts  
Pete Kay Comments: You actually do not need to remove the drive shaft to get the rear coil spring to come out. All that needs doing is a string push down on the trailing arm and spring will have enough clearance to be removed. I've done it on my e 36 touring!!
July 13, 2011
  Followup from the Pelican Staff: - Nick at Pelican Parts

Thanks for the tip, unbolting the shock at the bottom will also help get more room to get the spring out.
 
zawe Comments: helpful information
June 22, 2009
  Followup from the Pelican Staff: - Nick at Pelican Parts

Thanks for the feedback
 

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