Front Suspension Issue
 

I have a 2006 x5 3.0 with 75k miles on it. The car rides well but over the last few weeks I have been experiencing a thump under the wheels each time I drive over uneven road surface, particularly at low speeds. I don't hear hissing so doubt its the strut. A local mechanic said to replace lower front control arms with stabilizer links, but I have been doing some research and not sure if its the bushing. Can anyone advise how to diagnose this problem or provide advice? I am in Central NJ so if anyone can recommend a mechanic I would appreciate it. Most of the mechanic are closed on weekends which makes it a challenge to address car troubles.

Thanks in advance for all your assistance.

Where exactly does this thump come from? Left side? Right side? Both? Does it change when turning? Torn CV boots can cause a thump, obviously localized to whatever side the noise if coming from. Bushings can certainly cause thumps. I would get under there and see if anything looks amiss.

The entire axle was changed last year because of torn boots and I inspected the boots and they are intact. The noise comes from both sides, but more on the side which is uneven, ie hitting the bump in the road. When turning there isn't a clicking or any noise for that matter.

go under the car and grab your thrust arm and shake it back and forth, if you can see small rips/tears in the bushing then the bushings are shot.

if there is excessive play in the arm you would want to replace those, I realized a lot of clunking came from them before they were replaced.

Yeah, sounds like it might be sway bar related then. Bushings or end links seem like the most likely culprits. End links are easy to swap out and are pretty inexpensive, as I recall. I'm not sure what's involved with replacing bushings.

Sway Bar links are nothing more than a stick with two swivel ball ends. One bolted to the sway bar the other end to the suspension arm. easy to replace. Any movement means they are bad. Think stick in a barrel. Does it wiggle? = bad.
You will need a metric open end (16?), a 16 mm thin open end, and another 16mm box end. There more than afew videos of how the change them. Hose them down with WD40 1/2 hrs before and unbolt them.

The thin open end will allow you to hold the shaft while turning the nut. These thin wrenches are on amazon (cheaper to buy the set then the one size you need.)

Replacements are of three levels:
Upgrade: HD versions $30
OE: $36-46
China cheap: $10-17 (Uro)

I would recommend leveraging these three vendors in the USA:
ECS Tuning: OEM / Performance / Maintenance / Repair / Replacement Parts and kits for Audi, BMW, Mercedes Benz, Mini, Porsche and Volkswagen - ECS Tuning
Eeuro; European Auto Parts - Wholesale Genuine and OEM Saab BMW Volvo Parts
FCPEuro: Lemforder Parts | FCP Euro
Recommended Brands: Meyle HD, http://c1521972.r72.cf0.rackcdn.com/.../Lemforder.gif, OE BMW

#7 below Sway bar link
http://www.penskeparts.com/DiagramsM...png?v=03192010

Number 6 below is the control arm with bushing. Aftermarket ones have the bushing installed. Ball joint is seperate part.
http://www.penskeparts.com/DiagramsM...png?v=03192010
http://dyw03owr7vs3n.cloudfront.net/...jpg?1397595341http://dyw03owr7vs3n.cloudfront.net/...1s.?1393412368
Helpful?

Very informative StephenVA! I agree that the thin, open end wrench is a must-have. With a regular wrench, you will likely damage the rubber boot on the end link joints. Just as a heads up.

Good post Stephen... I have the same clunking described by the OP, got under the car, and sure enough the bushings on the tension/torsion/control arm (seen them called so many different things) are shot. Going to replace the ball joints at the same time since I just bought this and figure it all probably has the same 111,000 miles on it.

On My X5 4.8is, the first set of control arms lasted 42K with 60% town and country driving (8 years). Rears were replaced also at the same time. Hell why not? Too many hard take offs.