E90 - Steering/Humming/Braking/Clunking Q's

[akennedy]

Hey all - looking to sort out some things on my GF's 2009 328i. It's at ~140K miles and still looks good, but is far from the Ultimate Driving Experience. Wanted to run my thoughts by the forum before dumping money into the car.


Steering feels incredibly heavy - heavier than my Jeep on 35" tires. Literally just feels like there is no power steering. It has a traditional steering rack - not the electric assist. Doesn't seem to be too noisy.

• I replaced the PS pump, lines, and fluid reservoir last year and it did nothing.
• Ive read people say the lower steering shaft U-Joint can get bound up, and to soak it with WD40 overnight then hit it with white silicone the next day (or replace it because it's a contained unit, but the WD40/White silicone seems to have good results)
• If that doesn't work, would think there are issues with the steering rack, but doesn't seem to be the same signs/symptoms?

Humming from front right, almost like a wowowowowow sound at slow speeds that speeds up with speed. First thought is bearing/hub assembly. Second thought is rotors. Third is warped rim

• To check front hub/wheel bearing, jack up car, spin tire and listen. Check for wiggle at wheel where rest of suspension doesn't move
• Rotate wheels front to back (I believe tires are directional) and see if sound in same place
• Could be rotor/pad as well?

Shimmy/shaking on hard braking at higher speeds only.

• Rotors and pads? Car seems to brake fine though in general and no brake pad light on
• Thrust rod bearing?
• Tie rod ends or other steering components?
• Warped/bent wheel?

Clunk on rear when hitting potholes

• Shocks worn out? (Can hear gas noise upfront when going over bumps, so probably due for struts/shocks anyways)
• Springs Shot?
• RTAB (remember this from my e36 and e46)?

All thoughts and help greatly appreciated!


Alex

[SlackTube]

You seem fairly knowledgeable and I think if your willing to dump some time/cash into the car it should ride excellent again. Not to beat you up but it seems she has kind of neglected it for a while and may take some reconstruction to make it right. It's hard to diagnose issues over the Internet but most of your logic seems dead nuts except a few tweaks...

steering: depending on model some E90 have stiff steering but it shouldn't be feeling like there is no power steering. I'd say the lower steering shaft is an excellent place to start but I've never seen PB and lube fix it merely temporarily band-aid an issue.

humming: check your tires carefully first especially runflats. Try swapping tires around and see if the noise changes and Check for irregular wear and feathering. I've seen 100X more tires causing noises then anything else.
next step is wheel bearing but it's unlikely you'll be able to feel any play in it or be able to spin it fast enough to duplicate the noise. You need a lift and to drive the vehicle in the air as most bearings don't make noise until about 35 mph+ unless they are wasted. Try driving the car and get going like 35+ or whenever the noise is loudest and take turns ( picture sweeping offramp ) see if the noise changes. Most likely it's tires or wheel bearing.

shimmy/shake: most likely warped rotors but thrust rod bushings do have significant role in keeping a firm reliable steering wheel and pedal. It's not a bad idea to replace thrust rod bushings anyways as they typically last anywhere from 50-75K. Usually you will feel thrust rod bushings during normal driving when hitting bumps the steering wheel wobbles a little or if you stab the brake at slower speeds you feel the front wheels shifting forwards. I'd start with rotors but TRB are never a terrible idea.

Clunk from rear: your rear shocks have rusted out the tops and leaked all the fluid out. Look under the car for the shocks being wet or accumulations of dirt as the dirt sticks to the hydraulic fluid.
ive never seen E90 rear springs bad.