Juddering under hard launch

[benjj]

Hello chaps,

My M535i has got a little niggle - it has a judder when you give it full throttle but only from stationary.

It has a new and balanced prop shaft and is pretty much entirely rebushed.

There is zero juddering once moving, you can drop down to 2nd and floor it and all is fine - it is just from a standing start when you absolutely pin the throttle.

Could it be the diff mount?

Any suggestions very welcome.

Cheers,

Ben

[D.]

Usually that means a bad center bearing on the driveshaft. Vibration on starting off and quiet at speed. But you say it's all new down there. I wonder if the slight pre load forward on the center bearing was accomplished. Another idea, I'd look at the rear subframe bushings. Is the rear helping to steer? Moving you around, making you correct a lot?

[benjj]

Interesting point on the subframe bushes, I've got spares of those so will have a look. I'm over at the workshop today so can check.

Interesting on the pre-load of the prop bearing. The work was done before I bought the car so will investigate.

Thanks, appreciate it.

[wkohler]

Sounds like you should check the preload. Simply push the bearing yoke forward 1/4" before fully tightening. A non-preloaded bearing will tear itself apart in short order.

[D.]

This could be a badly worn driveshaft centering sleeve. The rubbery piece in the very front of the shaft. The nosecone. I've seen 'em loose on my jobs. Just learned they're available. $12 part. Fits both e12 and e28. part #26117526611

[wkohler]

Easy to change if you have a grease gun. Bread trick might work too.