Parts Catalog Accessories Catalog Tech Info Tech Forums
 
Follow Pelican Parts on Facebook Follow Pelican Parts on Twitter Follow Pelican Parts on Instagram Follow Pelican Parts on YouTube Follow Pelican Parts on Pinterest Follow Pelican Parts on Tumblr
  Search our site:    
View Recent Cars  |   Cart  | Project List | Order Status | Help    
 
Get FREE Ground Shipping with the purchase of $75 in qualifying parts!
 


Pelican Technical Article:

Replacing Front Shocks and
 Springs on Your BMW

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

  This article is one in a series that have been released in conjunction with Wayne's new book, 101 Performance Projects for Your BMW 3 Series.  The book contains 272 pages of full color projects detailing everything from performance mods to timing the camshafts.   With more than 650+ full-color glossy photos accompanying extensive step-by-step procedures, this book is required reading in any 3 Series owner's collection. The book was released in August 2006, and is available for ordering now. See The Official Book Website for more details.
 
Need to buy parts for this project? Click here to order!

[click to enlarge]

     Another popular project among BMW 3 Series owners is replacing the front and rear shocks. Replace both the front and the rear at the same time, as they take roughly similar abuse over their lifetimes, so neither is likely to be more or less worn than the other. The shocks should always be replaced in pairs (left and right together, see Project 61).

     I recommend that you replace your shocks every 50,000 miles or so, or if they start to show signs of fading or wearing out. If you push down on a corner of the car, it should spring back with little oscillation up and down. If the car bounces up and down, you probably need new shocks. Different driving patterns may also affect the life of shock absorbers. Cars that are raced or often driven on winding roads may need their shocks replaced more often. It is also important to remember that, if you install performance springs that lower the car from its stock level, you will need to have the car realigned. Changing the height of the suspension also changes the values of the alignment settings.

     The replacement process is somewhat similar for E30 and E36 cars with one glaring exception: E30 cars have a replaceable front shock (called a “strut insert”), whereas E36s require you to replace a more complex integrated shock absorber/strut assembly. Although the E36 design requires the replacement of a more complex part, its replacement procedure is actually easier.

     Begin the process for both E30 and E36 cars by jacking up the car and removing both front road wheels (see Project 1). E36 owners should read the following E30 section and then the subsequent E36 section, as there are elements of the strut disassembly process that are not specifically mentioned in the E36 section below.

E30 chassis

     With the car elevated (see Project 1) and the wheels removed, start with one strut, and remove the brake caliper (see Project 57). Unplug any brake sensors connected to the caliper, and disconnect the caliper from the strut. Use rope or wire to tie the brake caliper aside so it doesn’t hang by its rubber hose. With the brake calipers secured out of the way, disconnect the tie rods from the struts (see Project 59). It is difficult to disconnect tie rod ends from struts without damaging the rubber boot that protects the tie rod. Consider replacing the tie rod ends at the same time if you think you might damage the boot.

     With the tie rod disconnected, you should be able to rotate the strut quite easily. Now, disconnect the sway bar drop link from the control arm (see Project 59). This allows you to drop the strut downward to its lowest point, so that you can pull it out from the car after you remove the shock insert and spring.

     Next, install the spring compressor onto the spring and compress it until it no longer is tight in the strut assembly. While compressing the spring, be sure yo wear safety goggles. These springs are under a lot of pressure, and the spring compressor could suddenly slip off. Place the two halves of the compressor on exactly opposite sides of the spring. You may use two ratcheting wrenches (I prefer the ones manufactured by GearWrench) on each side of the compressor to ensure even and equal compression. Failure to maintain even compression when compressing the springs can make the compressor slip off.

     With the spring compression removed from the strut assembly and the springs loose on their perches, now move to the engine compartment. Pry off the small black cap in the center of the strut mount, and remove the center nut attached to the top of the shock. This, of course, is easier said than done. If you have an impact wrench, simply zap this nut off. The reassembly process requires an impact wrench, so if you don’t have one, now is a great time to buy one. I recommend electric impact wrenches that function without an air compressor is required (see Tools of the Trade in the front of this book).

     If you don’t have an impact wrench at this time, remove the nut by latching onto the top of the shock rod in the wheelwell with some carefully placed locking pliers, in between the springs. This is not the best method for removal, and if that top nut is on really tight, it may not be possible to remove it this way. If that’s the case, disconnect the entire strut from the car by disconnecting the lower ball joint (see Project 59). Once the strut is out of the car, you have a few more options for removal, including taking the entire strut over to someone who has an impact wrench.

     With the top nut removed, place your floor jack underneath the bottom of the strut to relieve some of the pressure from the weight of the strut assembly. Next, disconnect the three nuts that hold the top shock mount to the chassis, and lower the strut. Reach up inside the wheelwell and remove the top strut mount, the upper spring retaining plate, and the old rubber gasket.

     Now you’re ready to remove the shock insert. Remove the dust cover from the insert and you will see a threaded collar that secures the insert to the strut housing. Lubricate this collar a bit with WD-40 or similar penetrant, as you don’t want to damage the threads of the strut. You can use the special BMW tool designed to fit this collar, but I found it just as easy to use a plumber’s wrench or a set of channel locks, to loosen it. Once the collar is loose, pull the shock up through the top inside the engine compartment. It’s normal for the older-style hydraulic shocks to be submerged in oil, so be prepared that oil will leak and drip everywhere as you pull the shock out. Have paper towels handy.

     With the shock removed, lift the old spring off of the bottom spring perch. Swing the strut out and look down the tube with a flashlight. If the old shock inserts were conventional hydraulic shock absorbers, there should be oil in the bottom of strut. The oil is used as a lubricant and also aids in heat dissipation. If you are going to use new hydraulic shock absorbers, siphon out the old oil and replace it with about 1 quart of new oil. You can use regular motor oil for this. If you are using replacement gas shock inserts (like the Bilstein units), siphon out the old oil in the strut and install the new shock inserts dry.

     If you reuse the old springs, simply place them back onto the top of the lower spring perches. If you replace your springs with new ones, move the springs to your workbench and slowly release the spring compressor on your old springs. Compress the new springs in a similar manner. The E30 shown in this project was upgraded to Eibach performance springs, which created a stiffer suspension and lowered the car about 1.8 inches in the front and 1.5 inches in the rear.

     Install the compressed spring assembly back onto the lower spring perch. Install the new shock absorber through the top of the engine compartment, and tighten the collar to the strut. Reinstall the dust boot/rubber bumper assembly over the shock to protect it from road debris and grime. The Bilstein sport shocks installed on this car have the boot and stopper already integrated into the assembly.

     Reinstall the upper spring plate and spring pad, and verify the plate is nestled correctly against the top of the spring. Inspect the upper strut mount carefully. This part is manufactured out of rubber and has an integrated ball bearing inside. It will wear over time, so replace it if it looks old, or if it hasn’t been replaced previously. Reinstall the upper strut mount on top of the spring plate, and zap it on with an impact wrench. Unfortunately, the impact wrench is pretty much required here—do not use pliers on the shaft of the new shock inserts.

     Once the shock rod nut is affixed, have an assistant raise the strut assembly with the floor jack while you guide the upper strut mount into place. Reattach the three nuts. Now, carefully release the tension on the spring compressors and the spring should seat between the upper and lower perches. Reattach the sway bar drop links, tie rod ends (Project 59), and brake caliper (Project 57). Plug in any sensor connectors you may have disconnected, and route the wires and hoses back through the tabs in the strut.

E36 chassis

     With the car elevated (see Project 1) and the two front road wheels removed, start with one strut and disconnect the brake sensors and brake hose from the strut. They are wedged into a mounting tab in the strut and held in place with rubber grommets. Slide the grommets out of the tabs; this may require some gentle nudging with a screwdriver. Then, remove the upper mounting bolt for the strut. Hold the nut on the other side of this bolt with a crescent wrench. Remove the two lower bolts as well. Place your floor jack underneath the bottom ball joint and lift up on the strut about 1/8 inch to support the weight of the strut when you disconnect the top from the chassis.

     Moving to the engine compartment, remove the three small nuts that hold the upper shock mount to the chassis shock towers. At this point, the strut should be free to be removed from the car. Lower the floor jack and press down slightly on the control arm, and pull the strut out and away from the car. Don’t let the steering arm assembly hang. Tie it up with rope and wire, as you don’t want to damage the outer ball joint or rubber brake hose.

     Take your strut assembly over to your workbench. Compress the spring using the procedure discussed in the above E30 section. Remove the top nut from the shock, also using the procedure discussed in the E30 section. Again, it is very difficult to remove this nut without an impact wrench. Move your spring to the new strut and reassemble, using all of the hardware from the old strut. As with the E30, inspect the top shock mount to see if it needs replacement. Zap in the new top mount with the impact wrench and reinstall the entire assembly into the car.

     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.

Figure
Figure 1
E30: With the car on jack stands and front road wheels removed, remove the brake caliper (yellow arrow; see Project 57) and disconnect the brake pad sensor and ABS sensor wires (Project 51). Detach any hoses and sensors that may be clipped to the strut housing (green arrows; E30 shown in main photo, E36 inset photo).
Figure
Figure 2
E30:  Now, disconnect the sway bar drop link from the control arm (left) and disconnect the tie rod from the strut (right) to gain enough maneuvering room in the control arm to remove the front strut.
Figure
Figure 3
E30: Install the spring compressor onto each side of the spring. Be sure to space the compressor equally on both sides. I use a pair of ratcheting wrenches to compress the springs—it turns a 45-minute job into a five-minute task. I recommend the ratchet-style wrenches manufactured by GearWrench.
Figure
Figure 4
E30: This photo shows the center nut removed and the three nuts that hold the upper shock mount to the chassis. Use an electric impact wrench for best results.
Figure
Figure 5
E30: Remove the collar (green arrow) in order to remove the shock absorber from the strut.
Figure
Figure 6
E30: The E30 chassis’ strut design incorporates a replaceable shock insert. With the springs removed, the insert should pull out from the strut. Support the strut carefully, and don’t let it hang on the lower ball joint; the weight of the strut can damage the joint. Use a piece of wire or a few tie wraps to secure the strut, or place a support under the brake disc. The inset photo shows two new E30 front strut inserts (gas shocks) manufactured by Bilstein. Bilstein shocks are the gold standard for German strut inserts, and one pair typically lasts the life of the car. These come complete with new dust boots to protect the top of the insert rod. For E30 cars, simply place the new inserts inside the strut (without any oil), and reassemble the spring and mount assembly on top of the insert.
Figure
Figure 7
E36: The E36 shock and strut are integrated. While this makes for a more expensive and more complicated part, it also makes the replacement process quite a bit easier.
Figure
Figure 8
E36: Push the sensor wires (green arrows) and the brake hose (yellow arrow) out from the brackets in the strut. They are attached to the strut by rubber grommets. With the hose and wires detached, remove the upper bolt (blue arrow) that connects the top of the strut to the steering arm assembly.
Figure
Figure 9
E36: The two blue arrows here show the two lower bolts that secure the bottom of the strut to the steering hub assembly.
Figure
Figure 10
E36: With the bottom of the strut disconnected and supported by your floor jack, remove the three nuts at the top of the strut tower in the engine compartment. With these nuts removed, lower the strut with the jack.
Figure
Figure 11
E36: With the strut removed, the steering arm assembly will hang loose. Tie up the assembly to prevent damage to the ball joint or the rubber brake hose that connects to the brake caliper. If you look closely, you’ll see the rubber of the brake hose (red arrow) is cracking and should be replaced as soon as possible.
Figure
Figure 12
E36: Like the E30 strut, the top nut is very difficult to remove without an impact wrench. Bite the bullet and pick up a good electric impact wrench, as you will certainly find use for it on other projects.
  Looking for more photos?  Click to see bonus pictures for this project.
Need to buy parts for this project? Click here to order!
Comments and Suggestions:
bonebreaker Comments: e36 m3 1995 and 328i shocks are not the same but i can fit a 1995 328i shock in a 1995 m3?
thanks
November 13, 2014
  Followup from the Pelican Staff: No, I do not believe they will fit. The 328 did have an Mpackage sport shock that would work.- Nick at Pelican Parts  
mohd Comments: Hi
Bmw e93 335i m package with standard suspension

It is time to replace front strut assembly and rear shock absorber

Can I replace them with sport suspension as below item # ??


31-31-6-785-589-

31-31-6-785-591

What is the advantage of both??

Should I replace other parts to make the car better specially in bad road?

Appreciated
October 18, 2014
  Followup from the Pelican Staff: I am not the best at part number application. Give our parts specialists a call at 1-888-280-7799 and they can help figure out which part or repair kit you need.
- Nick at Pelican Parts
 
Adrian E36 Comments: The instructions in your book were a BIG help and I recommend it to any DIY'er with an E30 or E36! It told me everything I needed to know to perform this task on my E36, step by step.
June 13, 2014
  Followup from the Pelican Staff: Thanks for the feedback. Glad we could help.
- Nick at Pelican Parts
 
theonetruetom Comments: I have something to add to this: It's a *really* good idea to have a helper when you're reinstalling the strut/spring/hub assembly on an e30, especially if you did it like I did it and removed the spring compressor before you put it back in the car. Specifically, the helper needs to make sure that all 3 bolts on the strut mount are going into the right place on the strut tower. Right now my struts are held on by 2 bolts because the 3rd one both sides came out of the splines that hold it in place.
May 9, 2014
  Followup from the Pelican Staff: Thanks for the additional info. We appreciate it.
- Nick at Pelican Parts
 
Jandxjets Comments: On the two lower strut mount bolts, in between them is that centering pin. I CANNOT get that to line up after hours it is still off by an 1/8 of an inch or so. I'm going to drill out the hole for the centering pin very carefully to open it up just enough. I'm assumig this isn't advised? But I have no other options. Your thoughts?
April 2, 2014
  Followup from the Pelican Staff: DO not drill it out. Have you tried cleaning the nub on the spindle with emery cloth? Corrosion may be stopping it from going in. - Nick at Pelican Parts  
scotty Comments: any idea on how much torque is needed for an impact gun? 250ft.lbs is what is feasible right now for me.
March 24, 2014
  Followup from the Pelican Staff: I don't understand the question. An impact gun has a max torque, set by the manufacturer. - Nick at Pelican Parts  
SDHR Comments: Does the E36 also need to so the spring compressor stuff? It is not clear. Thanks
February 24, 2014
  Followup from the Pelican Staff: Yes, you will need a spring compressor. - Nick at Pelican Parts  
bimmer7guy Comments: Hello
I am having an issue with the upper bold on the strut figure 8, blue arrow I was able to remove the nut off of this bolt but bolt is stuck been anyway I have removed to caliper removed the lower bolts on the hub an removed the nuts except one on the strut tower holds it from falling but I am unable to remove it an even with the strut down there is no play between strut qn the hub what to do
January 19, 2014
  Followup from the Pelican Staff: Does the bolt spin or is it seized? If so, you have a few options, you can soak it and try to drive it out with an air hammer. Or you can cut the ends off to remove strut. Then try to drill out remaining part once it is out of vehicle. - Nick at Pelican Parts  
tmachine Comments: The only issue I am having is finding a socket that fits the top nut. The only size I don't have is 22mm so I assume thats the size. Any input on what socket fits is much welcomed.
October 23, 2013
  Followup from the Pelican Staff: Some of the factory nuts are 22mm,
- Nick at Pelican Parts
 
Bimmerman4ever Comments: Actually it's easier to remove the strut first, then mount the spring compressor tool to swap out the springs. In the photo the tool is mounted within the wheel well, which is damn near impossible to do with some tools. Just remove the strut mounting bolts in engine bay do not loosen the strut insert center nut until you have the strut assembly off the vehicle.
July 9, 2013
  Followup from the Pelican Staff: Thanks for the additional information. We appreciate it.
- Nick at Pelican Parts
 
rogerd Comments: I had no problem installing the left side. The right is having problems getting the shock mount lined up,the upper bolt is in place.I can move the steering arm left and right a little. Do I need to unblot the sway bar?
October 17, 2012
  Followup from the Pelican Staff: You can more the steering arm to help line it up, the sway bar should not have to be unbolted.
- Nick at Pelican Parts
 

Got more questions?  Join us in our BMW Technical Forum Message Board, and ask a question to one of our many automotive experts.
  Search our site:    

View Cart & CheckOut | Project List | Order Status |  Help    

 

[Home] [Customer Service] [Shopping Cart] [Privacy Statement]
 [Contact Us] [About Us] [Shipping] [Map to our Location]

Copyright © Pelican Parts Inc.