Replaced all shocks/struts

[Stubbie Blue]

Just replaced all 4 shocks/struts on my 2012 135i Coupe with 52,000 miles. At first I noticed that the bump stops were completely deteriorated, and figured that the shocks would probably have to be replaced too. (After removing them, they indeed did not extend back out when compressed).

An independent shop wanted $2,700 to do them but I didn't want to spend that much on a car this old, so I decided to DIY. It was a really hard job but I'm still glad I did it. I didn't take many photos or any video because it was so hot and sweaty working in my garage here in Florida, but here are some basic notes on the job:

I got Sachs shocks/struts and bump stops for $300.

Rear shocks were easy.
- Remove trunk liner to get to top shock nuts - 16 mm offset wrench or passthrough socket with a 6 mm counterhold.
- Bottom nut is 17 mm with a 15 mm counterhold on the shock body.

Front struts were a lot harder.
- I didn't do it, but next time I would probably remove the brake calipers.
- Remove the sway bar link - 16 mm nut with a 17 mm counterhold on the other side.
- Tie rod ball joint - 21 mm nut, Torx T40 counterhold.
- Remove front undertray. I think there were 19 x 8 mm screws including 2 on the sides in the wheel wells.
- Loosen but don't remove both lower control arms - 18 mm. I also removed the rear LCA ball joint at the knuckle - 21 mm/T40.
- Strut pinch bolt - 18 mm, then use a strut spreader tool. You can then slide the knuckle down off the strut.
- 3 x 13 mm nuts on the top strut mount but one of them is under the strut brace.
- First I tried one of these common spring compressors: https://www.amazon.com/dp/B092J19D6Z
- Even when compressed down all the way, they still left a bit of tension on the top strut nut (original was 18 mm, 6 mm hex/Allen counterhold, but Sachs strut nut was 21 mm/H6). So while I could still remove it (and the strut mount popped off), I couldn't put the strut mount down enough on the new strut shaft to get the nut back on.
- So I got a different style spring compressor: https://www.amazon.com/dp/B09DGKMBYM
- And eventually managed by putting the top fork of the compressor on the spring seat (i.e. this part: https://www.amazon.com/dp/B06X17KL37) instead of the spring itself.
- You have to be very careful that the spring seat does not slip out of the holding lip on the fork, so rotate the spring until it fits best. I had it so that the part of the spring seat that dips from high to low was near the center of the fork behind the lip. I used ratchet straps just in case so the spring wouldn't go flying if it slipped out.
- If the spring starts to bend as you compress it, you can try using one of the common spring compressors on the outside.

[WrathOTM]

Always happy to see someone DIY the suspension. The fronts are kind of a pain, sort of. In my case, with the springs compressed enough to allow me to tighten the bolt had the spring compressor get stuck on the spring once uncompressed.

[an3ony]

Did my front and rears over 2 weekends this October. the rears were a 3 hour deal for me, but the fronts were a bit more difficult, I also did the front control arms and tie rods.
Seeing your spring compressor setup, I wish I'd have seen that prior to doing this as getting enough spring compressed was the biggest issue I ran into.
I also added BMW's strut mount plates to try to keep things from punching through the strut mount in the engine bay.

[gjm120]

If you are going to do this more than once, I would buy the horseshoe type strut spring compressors. Much safer and easier.

[lucahemi@gmail.com]

Originally Posted by gjm120

If you are going to do this more than once, I would buy the horseshoe type strut spring compressors. Much safer and easier.

Can you rent those from autozone / oreilly?

[gjm120]

Originally Posted by lucahemi@gmail.com

Can you rent those from autozone / oreilly?

Don't think so. From what I've seen they only rent/loan the hook types. I think you can get the horseshoe style for around $125-$150. I've used mine for my 1er and other cars.

[mkeiser]

this job is on my list for next year... kind of dreading it but it's overdue.

[gnuels]

I'm looking into the same job and am a little overwhelmed with the choices for struts / springs / coils. Bilstein struts seem to be hit and miss with leaks? Is there a consensus choice for a sport suspension equivalent? I'm not looking for peak performance or adjustability so I think coils are out of the question for me.

[GoRomeo]

I had a local shop do this job for me when I bought mine. . Glad I did. Car feels like new ever since.

[gnuels]

What did they replace them with?

[GoRomeo]

I believe I got Sachs and Ballstein for front and back. Paid like $1300 labor and parts.

[Wazowski]

Replaced factory shocks/ struts with Koni Yellows (adjustable) at 140k miles (5.5 years ago). Kept factory sport springs. Awesome replacement for DD (better damping but not punishing).

[mkeiser]

I've been eyeing the Koni Special Actives and keeping my M Sport springs...

[blue135]

Went through the same question and have really enjoyed the SAs on my E88.

[Fishee]

Ha, good thread. The fronts were definitely a pain - exactly the same issue.
So, the horseshoe type for future reference?

Like this?
https://www.amazon.ca/ATPEAM-Macpher...cx_mr_hp_atf_m

[gjm120]

Originally Posted by Fishee

Ha, good thread. The fronts were definitely a pain - exactly the same issue.
So, the horseshoe type for future reference?

Like this?
https://www.amazon.ca/ATPEAM-Macpher...cx_mr_hp_atf_m

Yes. Still be careful!

[JustAnotherSportsCar]

Night and day difference riding on new Bilstein B6s in my 08 E88 compared to the blown stock dampers.

Possibly the best bang for the buck improvement I’ve done to the car, along with new upper strut mounts. Though getting those front springs off and on was a dangerous pain in the a$$. If I have to ever do it again, I’m buying a wall mount spring compressor. Also, had to have a machine shop take a lath to the socket for the upper strut nut. It was too thick to fit in the strut mount recess.

[gnuels]

Originally Posted by JustAnotherSportsCar

Night and day difference riding on new Bilstein B6s in my 08 E88 compared to the blown stock dampers.

Possibly the best bang for the buck improvement I’ve done to the car, along with new upper strut mounts. Though getting those front springs off and on was a dangerous pain in the a$$. If I have to ever do it again, I’m buying a wall mount spring compressor. Also, had to have a machine shop take a lath to the socket for the upper strut nut. It was too thick to fit in the strut mount recess.

Having replaced the dampers and mounts, if you had to do it again, would you still do the same route, or would you replace everything with a kit like a Bilstein B12 Pro Kit? I'm trying to decide for myself, and wonder if replacing the tired springs of an 08 at the same time is worth it or not.

[JustAnotherSportsCar]

Because I have a convertible, and they have a unique spring rate, I did not really want to mess up the ride much. It sits plenty low enough for me in stock form. I use it as a daily driver in the warm months, so I don’t need to be scraping everywhere.

If I had a coupe, then I’d be 50:50 on the decision. Regardless, the stock m-sport springs matched with the B6 shocks are a huge performance improvement. It is a real driver’s car now! I also have the M3 front control arms which seemed to make the steering heavier, in a good way. I also bought the m3 rear sub frame mounts, but I am electing not to install them. The car feels perfect to me right now.

[Stubbie Blue]

Originally Posted by JustAnotherSportsCar

Also, had to have a machine shop take a lath to the socket for the upper strut nut. It was too thick to fit in the strut mount recess.

For the original 18mm strut nut I was able to use the Harbor Freight Go-Thru Socket Set which goes up to 19mm:
https://www.harborfreight.com/sae-an...ece-62305.html

But the Sachs strut came with a 21mm nut so I had to get these strut nut sockets:
https://www.amazon.com/dp/B08X68D5GF/

They are still a pain to use because a hex bit on a 3/8" drive ratchet won't fit inside so you have to use a regular L-shaped hex key, and you can only turn the strut nut socket 180 degrees before the hex key hits it so you have to take it out and reposition everything.

My 21mm offset box end wrench wouldn't fit inside the strut mount either.

[JustAnotherSportsCar]

I think the machine shop only charged me $10 to take down the thickness of the socket wall. I had bought a large passthrough strut socket set on Amazon. Fairly cheap build quality, but got the job done. The spring is by far the worst part. I had to get 3 spring compressors on it to get them put back together even enough to keep the tools from binding on the sides of the strut mounts. Just terrible.