E46 front wheel imbalance / resonance ?

[DaveR]

Bit of an odd one...

60mph on an A road the other day and steering starts to shake, gradually at first then building to worrying level, just as if a wheel weight has come off and one of the front wheels is quite badly out of balance.

Reached my destination half a mile later so stopped, inspected (no missing wheel weights or visible signs of anything wrong) so drove home. No repeat occurence.

Before next trip, checked all tyre pressures with digi gauge. One rear slightly low. Corrected. Test drive up and down dual carriageway. No probs and car felt sweet.

Next day, drive 75 miles to destination, mostly DC and M25 still sweet. Half way home at the other end of the day and the steering shudder starts again. Worry. Slow down. It goes away and stays away for the remainder of the 20 mile trip home.

Any ideas cos I'm stumped! Both front control arms/bushes replaced a few years / 80k ago. Might the bushes have worn and need doing again? The wheels and tyres are perfect and the prob is intermittent like it's some kind of harmonic oscillation or resonance, possibly aggravated by slack in the system? Car feels absolutely fine for the rest of the time though.

[blondini]

It's probably suspension wear as 80k is a good innings, but here's a bit of a long shot. Next time it happens check the front discs to see if one is warmer than the other. You just need to place your hand close to the slots in the wheels and you'll easily be able to tell if one or the other is hot. I've just had a calliper seize up on an e46 and an occasional mystery vibration was the first sign of trouble.

[DJFish]

As above, had exactly the same symptoms before my offside front caliper seized completely.

Apparently E46s are notorious for it.

[giw12]

Had exactly the same symptoms and only when the offside front wheel was red hot did I figure it out.

One new caliper later and it's like a new car...all the annoying little wobbles and shakes have gone.

[DaveR]

Spot on, chaps.

It happened again. OSF caliper was uber-hot when I stopped and checked. That one was obviously seized and it turned out that the NSF one wasn't in much better shape so they both ended up being replaced.

As fate would have it, I'd already booked a service and bought some Mintex disc/pad kits for both axles as I knew they were pretty shot. All up then, most of the business end of my braking system is now new.

Just for good measure the bushes had split on both sides at the front too. They'd done 90k+ though so no surprises there. They had contributed to excessive wear on the inner tyre edges though so I now need two new tyres to get it through the MoT. All in all, a bit of an expensive day then.

Still with 150k on the clock and annual depreciation of zero now it's still a fab car and cheap motoring all in all. Especially when you have an ace Indie on your side!

[obscene]

80k is incredible for the control arms the way E46's seem to go through them. I'd suggest looking at new control arms/bushes and having a look at the brakes.