BMW E46 Strut Replacement – 3 Hours
A BMW E46 strut replacement requires a few special tools, but is very “doable” for the home mechanic. The money you will save doing it yourself will greatly outweigh your tool purchases.
The BMW E46 is iconic…in both it’s looks, incredible ride and handling. And although it’s looks may never fade, years of driving take a toll on the E46’s suspension…especially the front struts. The front struts take the bulk of the abuse from rough roads, pot holes, and the occasional ricochet off of the parking lot curb stop (yes..we have done it too).
The front struts on a BMW E46 are actually part of the vehicle’s suspension. Unlike the shock absorbers on the back of the car, the front struts are considered a structural component of the vehicle. But unlike the rear shocks, who’s sole purpose is to keep the car from bouncing down the highway, the front struts also keep the car balanced and are an integral part of the steering and alignment.
Signs that you are ready for a strut replacement are: the front end bottoms out when driving on rough roads or potholes; abnormal front tire wear (known as “cupping”), abnormal handling characteristics, and poor front end alignment.
Preparing for a BMW E46 strut replacement
Before ordering all of your parts and disassembling your vehicle, it is important to understand that you will need several special tools to do the job correctly. Having the correct tools will make the job go very smoothly and save you from creating a mess that you can’t put back together.
The first special tool you will need is the correct strut spring compressor. There are many spring compressors on the market, but most of them will not work for this repair. The popular “hook” style tool for example WILL NOT work on this repair due to its inability to compress the spring far enough to install the new strut.
There is only one type of spring compressor tool that will work correctly on a BMW E46 strut replacement…and that’s the plate (or fork) style compressor. The BMW Repair Guide recommends purchasing the Schwaben professional plate style compressor to do this repair. For more information on this topic, please read our article BMW Strut Spring Compression Tool – The Correct Choice for the Home Mechanic.
The other special tool you will need for this repair is a strut nut socket. In order to remove and correctly reinstall the strut lock nut, you will need a special socket that has a portion of it’s wall removed. Having a portion of it’s wall removed allows for the insertion of an allen key into the center of the lock nut, which keeps the strut shaft from spinning during disassembly. It may all sound confusing now, but please trust us on this one. There is no way to reinstall the lock nut and properly torque it to spec without the socket. And an improperly torqued lock nut on your strut can cause a lot of issues, including strut failure.
To complicate matters, original factory strut lock nuts use a 21mm socket and most aftermarket struts lock nuts use a 22mm socket. Do yourself a favor and order both sizes now, before you start the repair.
1. Required – choose the correct struts for your vehicle.
|Strut – front right 59562||1||31316759562||OEM Meyle, all standard suspension vehicles|
|Strut – front left 59561||1||31316759561||OEM Meyle, all standard suspension vehicles|
|Strut w/ sports suspension – front right 50792||1||31316750792||OEM Meyle, sports suspension only|
|Strut w/ sports suspension – front left 50791||1||31316750791||OEM Meyle, sports suspension only|
|Strut w/ M sports package – front right 82102||1||31312282102||Genuine BMW, M sports package only|
|Strut w/ M sports package – front left 82101||1||31312282101||Genuine BMW, M sports package only|
2. Required – purchase both parts
|Bump stop 94750||2||31331094750||Genuine BMW|
|Strut mount 52735||2||31336752735||OEM Vaico|
3. Optional (but recommended)
|Spring pad – front upper 91867||2||31331091867||Genuine BMW|
|Spring pad – front lower 96664||2||31331096664||Genuine BMW|
|Dust boot 94749||2||31331094749||Genuine BMW|
Tools and Supplies
Strut spring compressor – plate style
21mm strut socket
22mm strut socket
13mm socket wrench
16mm socket wrench
17mm socket wrench
18mm socket wrench
16mm open end wrench
6mm hex key wrench
Torque wrench – medium range
Pry bar – small
- Using a 17mm socket and breaker bar, slightly loosen lug nuts on front wheels while car is on the ground. DO NOT ATTEMPT TO REMOVE LUG NUTS! You cannot loosen front wheel lug nuts with a socket wrench or breaker bar when car is in the air.
- Jack and support the front of your vehicle using the Jack Stand Method as shown in our article BMW Jacking and Supporting for Repairs and Maintenance.
- Finish removing lug nuts and remove front wheels from vehicle.
- Starting on the left side of the vehicle, locate and identify the wheel strut.
- Remove the brake caliper line, the wheel speed sensor wire, and the brake pad sensor wire from the bracket on the backside of the strut. These lines/wires should be removed so they are not in the way when removing the strut.
- Use a 16mm socket wrench and a 16mm open end wrench to remove the stabilizer link bolt. The 16mm open end wrench is needed to keep the bolt from spinning while trying to remove it. Remove the link from the strut.
- Use an 18mm socket wrench to remove the hexbolt and bracket anchoring the king pin to the strut.
- Use a small pry bar to loosen the king pin clamp. The king pin and wheel brake assembly should easily slide off the end of the strut.
- Use a 13mm socket wrench to remove the three mounting bolts anchoring the strut to the inside of the engine compartment.
- Remove the strut assembly from the vehicle.
Disassembling old strut
- Before disassembling, note the orientation of the spring on the spring pads. Take photos of the strut to aid during reassembly.
- The first step in disassembling the old strut is to compress the coil spring. Use a good plate (or “fork”) style spring compressor to do this. A hook style spring compressor will not work on a BMW E46 strut replacement. Please read our discussion on this at the beginning of this article…or read our article BMW Strut Spring Compression Tool – The Correct Choice for the Home Mechanic.
- Install the plate style spring compressor on the spring as shown in the following images. Make sure to always wear safety glasses and gloves while compressing springs.
- Compress the spring as far as you can turn the tool (per manufacturer’s instructions).
- Remove the dust cap from the top of the strut.
- The lock nut must now be removed from the top of the strut. To do this, you will need a special strut socket as discussed at the beginning of this article. Depending on the brand of strut you are removing, you will need either a 21mm (BMW “factory” struts) or 22mm (aftermarket struts) strut socket.
- Place the appropriate strut socket on the lock nut. Insert a 6mm hex key wrench through the wall of the socket and into the top of the strut shaft (see image below). While holding the strut shaft with 6mm hex key, loosen the lock nut and remove. Depending on how seized the nut is, need to use a piece of pipe to hold the hex key and a breaker bar to turn the nut.
- Remove the front strut mount.
- Remove the dust sealing gasket.
- Remove the front flat washer.
- Carefully remove the front spring perch and upper spring pad.
- Very carefully remove the spring and put away in a safe place, Remember it is under a lot of tension…you do not want to kick it or have it drop off of a work bench.
- Remove the bump stop, the dust boot and the lower spring pad. Note that the bump stop may be completely deteriorated on older vehicles, and in some cases may not even be left on the strut.
Assembling new strut
- Reassemble the new strut in the exact opposite order discussed above. We have also included the following reference diagram for your use.
- Install the new lock nut. This may be a bit tricky…you may have to maneuver the new strut around until you can get enough thread through the strut mount to install the lock nut. Be patient…you can get it on with the plate style compressor. Use your strut socket to hand tighten the nut. The threads of the strut shaft should be at the top of the nut before you can release the pressure on the compressor tool (see image below).
- Carefully release the pressure on the spring compressor tool. Remove tool from spring. Note that part of the plates may get stuck under the spring when the presuure is released. If this happens, use a rubber mallet to gently knock them loose.
- Make sure then spring pads are lined up correctly (as discussed in step 1 above). If they are not, recompress the spring and readjust strut.
- Use a torque wrench and 6mm hex key wrench to tighten the strut lock nut to 64Nm (47 ft-lb). Since this is a relatively high torque, you may need to use a piece of pipe to hold the hex key while tightening.
- Reinstall the strut back into the vehicle. Make sure the pin on the strut mount lines up with the hole in the strut tower. Measure the flange of the mounting nuts before torquing…the flange width will determine your final torque value: 18mm flange 24Nm (18 ft-lb), 21mm flange 34Nm (25 ft-lb). You can see in the following photo ours are 21mm.
- The strut has two pins on the back of it that line up with the slot in the king pin.
- Using a floor jack, slowly raise the king pin onto the strut. Guide the pins into the slot. Keep jacking the king pin until it stops and the strut starts to compress. At this point the strut is set in the king pin, and the mounting bolt can be installed.
- The mounting bolt may be a bit corroded…spray with some PB Blaster or WD 40 to help reassembly. Make sure you have the right caliper line bracket…the left side has three slots/right side two! Torque the king pin mounting bolt to 81Nm (60 ft-lb).
- Lower the floor jack and remove.
- Replace the caliper/speed sensor/brake pad wear lines.
- Reinstall the stabilizer link and torque nut to 59Nm (44 ft-lb).
- Repeat on opposite wheel.
- Replace wheels and hand tighten lug nuts.
- Lower vehicle and torque lug nuts to 122 Nm (90 ft-lb).
BMW E46 Strut Replacement Finished
If you have any questions or comments, please feel free to contact us. And congratulations for Doing It Yourself!