[Jelle458]

So I have no idea where to actually put this, but I have a feeling it could be a problem in the drivetrain.

My 330i has started shaking. It changes randomly up and down in intensity but it only starts above 90 km/h.

It can shake so crazy much that my dashcam thinks I have a crash and will record an emergency video.

If I drive 130 km/h and back down to 90 km/h the shaking can stop completely and I can accelerate back up to 130 km/h without any shaking, and then after a while the shaking comes back.

I recently changed flywheel on the car, but recently is months ago so I doubt it's related.

Pressing the clutch does not stop the shaking.

So far what I have done is:
Change to winter tires (the obvious) but didn't work
Change the bearing on the Cardan shaft (not sure that word is correct, it's the shaft between transmission and rear diff)
Change the two rubber discs on both ends of the Cardan shaft. Those that go between transmission and shaft, and shaft and rear diff. The ones I had were pretty bad with fabric hanging out of them

None of these things fixed my issue, it is 100% the same problem.

When I changed to winter tires I checked the brakes to make sure they aren't stuck in a braking position. The brake discs move freely with the wheels off, no jamming there.

So my question is, where do I go next? I checked the drive shafts coming from the rear diff but they basically look brand new with no play in either the shafts or the rear diff.

Thanks for suggestions!

[Brian86]

It's the hand brake.

Loosen the preload on the the cable brake at the drum/shoe adjustment.

[wrongmark]

I was going to say sticking brake calliper somewhere. I could tell which of mine it was by just smelling each wheel and feeling for heat (without touching anything!).

[Jelle458]

Thanks to both answers and I actually think it's brake related too. I just got to work using the car, and it was shaking a lot.

I pulled the handbrake (Not violently) at 130 km/h but it introduced a different shake, so the car had two shakes at two different "hertz".

But, after releasing the handbrake and pressing the footbrake at about 120 km/h the shaking became very intense, and it was not a different shake, it was like the already shaking just became very intense.

When the car stopped shaking, so did the foot brake.

So it seems like it could be the front brakes. They are pretty new. I replaced discs, pads and caliber about 6 months ago, but I went for Ridex, the cheap ones.

After changing the wheels nothing looked bad or out of the ordinary, or felt bad. But I guess they can still be bad.

Immidiately after installing the Ridex stuff I did say to myself that I want Brembo next time, it was also Brembo before and you really do feel a difference.

I will use the weekend to disassemble the brakes to see if I can visually see what's wrong, and then replace with brembo.

[Jelle458]

Update...

I was very sure that this came down to the Ridex brakes, but the front brakes looked absolutely mint.

I come from an E39 where my rear brakes would constantly rust together because they were basically never used, and following that logic, when I just barely touch the foot brake and the car is shaking, in my head problem should be front brakes.

But surely the E90 is applying the rear brakes even with very light touch, because the right rear wheel was completely stuck. I couldn't move the wheel with the car lifted, like at all.

Once the spring thing on the front of the caliber was removed, the wheel moved freely.

I disassembled, cleaned and put grease on the gliders, but just using my hand on the brake was enough to get the caliber stuck again.

I found a shop that had 2 calibers in stock, purchased one for each side and changed them both, now the shaking is completely done.

So I got my problem fixed, and it wasn't related to the cheap brakes I purchased, and I learned that E90 apply the rear brakes probably a lot more than my old E39.