Project 46: Control

Project 46 is an on-going series that demonstrates common fixes and preventative maintenance tips, as performed on our own E46 330Ci. Click here to read our introduction to the series, and here for the second instalment.

One of the primary advantages of owning an E46 3 Series is that even though it is fundamentally a reliable car, it’s few faults are well documented and can be pinpointed easily. When we originally drove the 330Ci, it was clear that the vehicle displayed the classic E46 symptoms of worn control arm bushings and ball joints, with poor turn-in response and soggy feedback during cornering.

The Front Control/Caster Arm Set is one of our favourite products, for a few reasons. Firstly, the set makes installation quick and simple. You don’t have to pre-press ball joints and bushes onto the arms, meaning it’s just a matter of unbolting the old ones and bolting up the new ones. That’s a huge plus in our book, as you don’t need speciality equipment or a lot of skill to be able to do the job, other than a ball joint separator and a bit of patience. Secondly, as the arms are aluminium, it reduces unsprung weight, improving ride and handling in vehicles that weren’t optioned with the M Sport suspension. Finally, the ball joints in the Sport versions are designed to replicate the M Sport option, improving feedback and responsiveness. 

With the original control arms removed from the car and sitting in the light, it was clear just how tired the ball-joints were and the extent to which the control/caster bushes had deteriorated. The ball joints look worse in the photos because of the force used to remove them, but they were physically very loose. With the car already on stands, we also decided to put a new flex disc (aka guibo/rubber donut) on the driveshaft. Although very soft, the original flex disc wasn’t particularly worn, but we know that once they start to go it can create a snowball effect, deteriorating quickly and placing undue stress on other more expensive components. This job is a little more labour intensive as it requires removing the exhaust and driveshaft, and might make life easier if you have a friend to help.

Once the Front Control/Caster Arm Set and new flex disc were installed, we hit the road to see the results. The most apparent and by far most surprising improvement was to the braking. We’ve never had any qualms with the way the 330Ci braked since we picked it up, but we were blown away with just how much more effective they became with the new arms installed. Braking improved because the chassis now has so much more mechanical grip, transferring the stopping power to the tyres, rather than the worn rubber suspension components absorbing the slack. It’s also much better now as the wheels no longer pitch forward, putting undue stress on other components, and allows the vehicle to grip on the correct area of the tyre. It’s a little hard to explain without a whiteboard, but the result is much better initial bike, and greater braking consistency on uneven surfaces.

As we expected, initial turn-in has also been restored. The front wheels can now be confidently loaded-up when coming into a corner, and without the fear that they will push wide as before. The steering is now more centered and doesn’t follow the camber of the road, and the flex disc has removed almost all of the driveline vibration. It’s made a huge difference to how the vehicle reacts on the road and how it responds to driver inputs.

These simple changes have brought the vehicle back to a good baseline, allowing us to shift our focus to other areas of the chassis. It’s also allowing us to now think about upgrades that might improve upon what we already have. Don’t forget to like our Facebook page so you can be kept up-to-date with Project 46.


New Mechanical Repairs:
Front Control/Caster Arm Set - $449
Flex Disc (Guibo) - $69
Total Cost of Repairs: $1575

New Non-Essentials:
Nothing this month!
Total Cost of Additions: $62

Total Cost To Date: $1637

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