Audi Multi-Link Suspension: Are MacPherson Struts Obsolete?
People always ask me what makes an Audi feel like an Audi. There is definitely something different about an Audi's handling characteristics, but it's too subtle to notice from inside the cabin. The answer lies in the front suspension design. If you've ever made repairs to your Audi or Volkswagen's front suspension and wondered why it has to be so complicated, I can assure you it is all there for a reason.
Multi-link suspension is second behind Quattro as the best reason to buy an Audi in my opinion. It's pleasant on the freeways, phenomenal in the corners, and gives the driver the confidence to push their car to the limits. Not all Audis feature multi-link suspension, and only a few Volkswagens use it. The A3, TT, and Q7 do not use it, as they are designed on Volkswagen and Porsche chassis, while the Phaeton and B5 Passat do.
Geometry can be easily controlled
The simple idea is to have multiple points of contact between the body and wheel. Rather than a Golf/Jetta setup, with just a control arm and strut, multi-link suspensions use as many as five control arms. The typical Audi design has a total of four control arms on each side (two upper arms and two lower arms), a strut assembly, and a steering rack mounted on the top of the firewall. By having so many points of contact spread across such a wide area, the camber, caster, and toe can easily be controlled even on rough road and under heavy acceleration and braking.
Essentially, an Audi's suspension setup is a double wishbone setup, but instead of one triangular arm on top or bottom with two bushings and a ball joint, you have two arms, each with a bushing and ball joint. This allows the wheel to move forwards and backwards with the loads and forces being put on it, in a controlled range, without changing the geometry too much.
But all this comes at a cost. A literal monetary cost. Rather than have one control arm with one ball joint and two bushings, Audis have four control arms on each side, with four bushings and four ball joints. These control arms are not difficult to replace, but can certainly break the bank if you don't do it yourself. If you suspect your front suspension is on its way out, it's not too difficult to diagnose and repair as needed.
If you hear a popping noise when going over bumps or turning when stopped, you probably have a bad ball joint. The simplest way to check is to lift the front tires off the ground and shake the front wheels from side to side. If you feel a popping or clicking, a ball joint has play, and the whole arm should be replaced. To isolate which ball joint it is, put your hand over the ball joints to feel which one is popping.
If your suspension feels loose or vague, it could be your bushings. The upper arms fail very often, and a simple visual check will tell you when they have to be replaced. With the wheels off the ground, turn them from lock to lock, checking the bushings as you turn the wheel. If you see deep cracks or very torn rubber, they should be replaced.
As with any suspension repairs, I recommend using high quality parts and having an alignment performed afterwards. Put everything back in the position you took it off, in order to prevent premature wear on the bushings and correctly preload them. There's no sense in replacing hundreds of dollars worth of suspension if it doesn't track straight and chew up your tires. If you take care proper care of your Audi or Volkswagen's suspension, it will take care of you.
Not only Audi uses multi-link suspension, so what are your personal experiences?
Written By: Chris Stovall
Chris is a journeyman mechanic from Berkeley, California, specializing in late model Volkswagens and Audis. A glutton for punishment, his spare time is spent rebuilding every component of his ’83 Rabbit GTI.