BMW DIY Video – How To Use A Spring Compressor, To Replace Struts or Springs
This DIY video will show you how to properly use a spring compressor tool to disassemble a front strut assembly or a rear coil-over shock and spring assembly that would commonly be used on BMWs and MINIs. We need to perform the spring compression when replacing shocks, struts or springs on the front of all BMWs and MINIs as well as the rear on most 5, 6, 7, 8, Z and X models and some 3-series models that have the spring mounted over the shock (coil-over).
We will be working with a front strut assembly (shock and spring) from a 2004 325ci E46 3-series. The exact procedure, as shown, would be applicable to all E46 models (3-series 99-05 – 323i. 323ci. 325i. 325ci. 325xi. 328i. 328ci. 330i, 330ci, 330xi, M3). However, the general procedure can be applied to all BMW or MINI front strut assemblies. This general procedure can also be applied to the rear coil-over type shock and spring assemblies, as noted above.
We will be using the BavAuto universal spring compressor tool. Use this video in conjunction with our various DIYs and how-to videos on shock, strut and spring replacement for various BMW and MINI chassis and models.
• Shocks/struts (Bilstein, Koni, Sachs, etc.), Sach original replacement shown in example:
• Sport or stock replacement springs, if desired (BMW, BavAuto, Eibach, etc.)
• Bentley Repair Manual
* Spring compressor:
* 3/8″ drive spark plug socket (13/16″ used in example)
* 1/4″ drive ratchet, extension and applicable socket as needed for end of shock
* 14mm through 8mm Allen keys as needed, for end of shock
* Combination wrench to match “hex” on spark plug socket
1) Remove the front strut assembly from the vehicle, using the applicable Bentley repair manual, BavAuto DIY instructions or BavAuto how-to video.
2) Determine which spring jaws are appropriate for the application. Assemble the jaws to the tool. Here, we have used the large jaws.
3) Assemble the spring compressor tool to the strut/spring assembly. It is preferable to attach the upper and lower jaws to the spring coils. However, if the coils that can be used do not allow enough compression for disassembly, the upper jaw can be affixed to the upper spring perch. In either case, BE SURE that the lock tangs on the jaws are securely wrapped around the coil or the spring perch. If this cannot be achieved, DO NOT attempt to compress the spring.
4) Use a socket and ratchet on the tool’s screw rack to compress the spring. Compress the spring until it is loose between the spring perches.
5) Remove the upper shock mount nut.
6) Remove the upper mount and note any washers that are in place on the shock shaft, for future use.
7) If the spring plate was not used for the upper jaw of the compressor, remove the spring plate. At this point the shock can also be removed from the spring.
8) If the upper spring perch was used for the seating of the upper compressor jaw, decompress the spring by “unwinding” the compressor’s screw rack.
9) Install a new upper rubber spring seat to the upper perch and a new lower rubber spring seat to the new shock’s lower spring perch.
10) install a new compression bumper and dust protection tube to the new shock.
11) Assemble the upper perch, spring and new shock, by compressing the spring in the same manner as was used for disassembly.
12) Install the new upper mount along with any washers that were removed when disassembled.
13) Install the upper nut, using the same tools as were used for removal (to hold the shock shaft and tighten the nut). DO NOT USE AN AIR GUN to tighten the upper nut.
14) Slowly detension the compressor tool while aligning the upper and lower spring ends with the spring seats and perches.
15) When fully detensioned, remove the spring compressor tool.
16) The strut or rear coil-over assembly is now ready to install into the vehicle.