In Reply to: Control arms and bushings... posted by JamesM on January 19, 2001 at 07:30:46:
I'm assuming the recommended replacement is due to the ball joints and not the arms themselves. Correct?
BMP also has balljoint dustboots. For street use would it be OK to just replace these occasionally when the old ones before they crack? They also have "special" balljoint grease.
My control arm bushings need to be replaced, since I don't track my car, but I do live in the pot hole capitol of the world, should I get aluminum control arms with the updated/stronger ball joints?
Do you need to replace the arms, too? Are the current balljoints worn? How many miles on them? At least get the offset control arm bushings. They are solid rubber instead of some rubber with a lot of airspace. Worn/dry-rotted bushings will allow the front to shimmy under cornering and braking. Worn balljoints will also do the same. If any balljoint boots are torn, replace both arms. Have your mechanic check the balljoint play. They use either a prybar or slip-joint pliers to check for excessive play. Some play (about 1mm) is acceptable, but consider replacement in a short while.
Now for the aluminum vs steel question. I would recommend that if you never track the car and don't plan on selling it soon, steel arms are just fine. The aluminum arms can cost more than double the price of steel arms. Turner's price is nearly $200 each! You can get the BMW OE steel arms (Lemfoerder brand) for about $80-100 each. I seriously doubt the aluminum arms last 2x longer for street use. If you just can't stand having cheaper parts, then get the aluminum arms. If you're selling the car in the next year or so, aluminum arms will matter to BMW enthusiasts--may help up the resale value. If you want to track the car at all, get aluminum arms.
I've read that the control arms should be replaced every 2-3years, well at least the bushings. It's kind of scary when you don't have control of your steering starting at 60mph and above.
Arms should be replaced religiously every 2 years (aluminum) or every year (steel) per BMW CCA Club Race recommendations. This means if you race the car (a lot), replace them whether they look bad or not. You can't disassemble a balljoint and check it without destroying it. The steel in the balljoints has a finite fatigue life, and the stresses imposed by racing (cornering and braking) will break them after a couple of years. For street use, the only thing you have to worry about is torn boots. The balljoints last so long that the rubber dust boots dry rot after several years. Once they crack open, it's about time to replace the whole arm. Potholes are nasty, but you'd have to bend a lot of rims before you should consider changing the arms.
I think everyone should have theirs inspected during their next maintenance. I'd hate to see our cars resting on a horizontal tire. By the way this happens often in this city.
Many state inspection shops (here in the US) are required to check for excessive balljoint play. They're pretty hasty to point out any faults, because they can make more money off of you if you need work done to get passed.
Where do you live, Magnus? Where is this "pot hole capitol of the world"? I know where the pot-head capitol is. :-D