01 325Ci Lower Control Arms

It's pronounced "chassy." Brakes, suspension...things that make the car fun or a death trap
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Adam
Posts: 2240
Joined: Wed Oct 23, 2013 9:50 pm

01 325Ci Lower Control Arms

Post by Adam »

Fun fact: the lower-trimmed E46 3 series cars used a different front lower ball joint design than the performance models (ZHP and M3).

What is that design, you ask? Why its a rubber-insulated ball joint, of course! So obviously, this needs addressing. Also both of the control arm bushings were very worn (also rubber). Conveniently, the ZHP-style lower control arms are a direct bolt-in for the other non-M3 cars. These arms have a pressed-in ball joint. I opted for these. Also, these arms have 2 ball joints in them. The normal one you expect at the spindle, then an inner one that mounts through the engine cross-member. More on that one later.

Here is a shot of a stock-style replacement. Notice the inset on the outer ball joint. That's where the rubber is.
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Here is a shot of one with the bushing attached.
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Taking the car apart is pretty straight forward. Pull the splash guard then pull the underbody reinforcement plate. Once this is done you can access the bolts that hold the bushing to the body (which come right off) and the nut on the inner ball joint. That's where everything went wrong.

The ball joint attachment at the spindle was not cooperative. I used a combination of spreaders, pickle forks, heat, and hammers to get those apart. All of those things fit in fairly well as there is reasonable access with the wheel off. The inner is another story, though. The passenger side one wasn't too bad, I was able to take the upper nut off with a wrench. The drivers, side one, not so much. I eventually was able to get a ratchet on it and get the nut most of the way off. That's when the stud broke free of the taper. Bad news. Using a jack to jam it back into the taper and vice grips on the shaft to hold it in place were unsuccessful. Fortunately I had a special tool.
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There's just enough space to get an angle grinder in there to cut the nut off the ball joint. However, there isn't enough space to cut all the way through the shaft. I ended up having to unbolt the steering rack and move it slightly forward and to the side to get that little extra room in there. Run times.

Got everything back together just before dark two weekends ago. Guess what? It drives terribly now (especially in the snow). The alignment is way off. The steering is way more responsive off-center but the toe is all wrong. I went and got new front tires (which it really needed) and asked for an alignment. They said it was 'all frozen up' and I'd need to replace stuff or try harder. They were able to get the rear toe back in spec. No charge for the alignment, so I can't complain too much.
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Adam
Posts: 2240
Joined: Wed Oct 23, 2013 9:50 pm

Re: 01 325Ci Lower Control Arms

Post by Adam »

So I bought replacement tie rods and boots, assuming the worst. Just over $100 for Moog stuff. Not too bad. Today I decided to try to free the factory stuff up before taking it all apart. I'm positive this stuff has never been replaced. Also, there's no play in either inner or outer so they aren't really bad.

I had soaked the adjuster nut in PB Blaster when I got back from the unsuccessful alignment, but even with that and some additional penetrating oil today, things weren't moving. So I used my MAP gas torch for about 30 seconds. Things freed right up. Sigh.

Here's some shots of the terrible toe-out. The drives side is the worst.
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I wound out the outer tie rods and applied a generous helping of anti-seize. I then used the very scientific string-from-the-rear-tires method to get as close to 0" toe as possible. After adjustment I used a tape measure across the front and rear of the front tires to get a total toe measurement. Looks like ~1/8" toe out. Not sure how this compares to the alignment spec as it is in degrees. If toe-out is negative angle, they want between 0.15-0.32 degrees of total toe-in if I'm reading it correctly. Regardless, it's way less terrible now.

So I took it on a shake-down run around Ocean Drive, as you do. I dodged enough tourists and made the following observations:
- There's no longer terrible bump-steer as the suspension moves around
- Steering feels way more precise after removing rubber between the wheels and the steering wheel
- The BFG Goodrich Advantage Sport tires it now has on all 4 corners are fine for an all season tire.
- This car doesn't have enough power to induce any significant throttle over-steer (although the DSC system might be partially to blame here).
- The (original) struts are on the soft side. You really notice this during hard transitions.
- The factory size sway bars are on the small size (more body roll than it should have).
- The factory calibration on the DSC system (Dynamic Stability Control) is WAY to aggressive. It would frequently initiate ABS on the front outer wheel as you approach the limits of the tire. During the transition from a hard corner back to straight and getting on the brakes hard would always trigger the ABS. There's a button to turn it off, which seems to turn it off. I'd need more time or perhaps better tires to see if it is all the way off.

Now to get back to the alignment shop to get everything straight(er). Now I need to replace all the rubber in the rear and replace that bent trailing arm seen in some other thread.
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