Brooklyn

Greetings all. Not sure if this is the appropriate forum for this question, but here goes. I've been told my ball joint boots all need to be replaced. Could someone explain to me what the ball joints do, and what effect they would have on the ride quality of the car? I have a '99 Passat 1.8t manual running Bilstein/Neuspeed Sport Shocks with Neuspeed SofSport Springs. Right now the bottom of the car seems to scrape whenever I go over any anamoly. I'm also getting a very loud moaning/creaking sound whenever the car is in motion or coming to a stop. Thanks in advance!

Raja Hamilton
'99 Passat K04

RangeR BoB

The ball joint is a joint that allows the front steering knuckle to rotate as well as move up and down.

If you look at the front suspension of your Passat (or an A4/A6) you will see the steering knuckle that the driveshaft passes thru and the brakes and wheel hub are bolted to. This knuckle must rotate right and left for steering and also move up and down with bumps.

The knuckle is attached to the car with 4 suspension links. The links are attached to the car with flexible rubber bushings (called control arm bushings, they are known to wear out and squeak after a time). The other end of the link attaches to the steering knuckle with a ball joint.

Because you have 4 links on each knuckle, you have 4 ball joints. A ball joint as the name implies has a ball crimped into a socket, so that it is free to move a certain amount in every axis, thus it can pivot (swing back and forth) as well as rotate. As they age, they wear down and become loose within the crimped socket. This shows up as play in your steering and possibly noise over bumps.

Should a ball joint weear excessively, it can separate. Periodically you will see a front drive car by the side of the road with a front wheel pointing out of the fender at a crazy angle. Almost invariably this is a balljoint that the owner allowed to get too lose, it separated, and the wheel/strut assembly came loose from the lower control arm. This is very bad as you can lose control of the car, you may break a drive shaft, and you will need bodywork to repair the fender being mangled by the front wheel when all said and done.

I would not hesitate to:

a) Get a second opinion about your ball joints

b) if this bears the same answer, get them replaced as soon as you can.

I don't want to sound like an alarmist. The risk is slight, but it is there. Ball joints are a critical part of your suspension, and not to be taken lightly.

Good luck, and safe driving.

Brooklyn

Bob, thanks for the detailed explanation. Looks like it's time for me to park the car until I find a mechanic I'm comfortable with around here.

Regards,
Raja Hamilton

RangeR BoB

Don't be paranid about them, but definitely get them checked.