Control Arm Vocabulary

[DBouts]

Hey yall,

I went to get some simple brake work done today, and my mechanic explained to me that I need to replace my front lower control arms, and if I do the front and the rear at the same time he will cut me a break on the labor cost. This not having been something I have done before I went straight over to Advance (Gold member with them) and asked for a quote on the parts. As per usual no one in the store could tell me exactly what I need. But to be honest the vocabulary is very confusing.

I need four lower control arms, but I guess BMW does not call them that. Is it only four pieces? They call them thrust arms? And is rearward mean lower? Im just looking for some clarification on this.

[Tarvis24]

On the front axle of an E90, generally the rear control arm is called the thrust arm, and the other is called the lower control arm. There are only two control arms on each side. So you need 2 lower control arms and 2 thrust arms.

[White94RX]

Not exactly, but close. The larger control arm, BMW typically refers to as the thrust rod. It goes from the spindle towards the front, and is bolted to the subframe. The rear, or lower arm, BMW typically calls it the wishbone. It's shorter, and is perpendicular to the wheel. It goes from the spindle straight out to the middle of the subframe.

[DBouts]

lem.JPG So when they told me I needed front and rear control arms they were talking about the front axle only?

I have a e92 328xi btw.

Are these the parts I need? Every single site uses different words to explain the same parts.

Thank you.

[DBouts]

Would this work?

https://www.fcpeuro.com/products/bmw...2-e90caxdrive1

[Tarvis24]

You're right I must have been thinking of another model, thanks for clearing that up

[Critter7r]

Not exactly, but close. The larger control arm, BMW typically refers to as the thrust rod. It goes from the spindle towards the front, and is bolted to the subframe. The rear, or lower arm, BMW typically calls it the wishbone. It's shorter, and is perpendicular to the wheel. It goes from the spindle straight out to the middle of the subframe.

That's the important bit, the "perpendicular" part. The control arms are perpendicular, and the "Thrust arms" or uper control arms, are diagonal within the front suspension. The shop is giving you a break on the price, because they're so close to each other, and the work is easily combined.