Knocking noise from front nearside wheel - HELP

[ducatipolo]

Hello, I am a Newbie on this forum and i would like some help PLEASE to diagnose a problem with my sons VW Polo 1.2 S which is an 07 car with around 103k miles and in good condition generally. Several weeks ago he mentioned that the Polo was making an intermittent 'noise' from the front nearside wheel area and on a couple of occasions took me out in it to listen to the 'noise', needless to say the noise did not appear for me to hear so i put it down to a sporadic gremlin which all cars seem to have but generally don't cause any trouble. Recently my own VW, a Sharan TDI 130 was off the road whilst the front suspension was overhauled and i used the POLO on several occasions; sure enough i started to hear the noise myself, it sounded like a gentle knocking on wood and it seemed at first only to appear when turning right and and accelerating, as soon as the wheels were straight ahead the noise would stop. On some journeys the car behaved normally, but on others especially turning right the knocking noise would appear. Experimentation showed that the noise would only appear when accelerating, the level of noise would increase the more pedal you gave it, on a light or trailing throttle the noise would disappear; as time went on the noise got increasingly loud from a knock on wood sound to a real clonking sound in time with the speed of the wheel. If the clutch was depressed and the car put into free wheel the noise would disappear, the noise does not seem to be gearbox, clutch or engine related, i suspect it is a drive shaft or wheel bearing problem but i am not sure, this is a guess. Is this sort of problem well known for this model? we are well aware of the cylinder head prob's associated with this 3 cylinder engine but this engine and gearbox is as sweet as a nut. Today my lad went up the road in it but came back after 10 mins saying it sounded too noisy and serious to drive. We jacked the car up and saw that the rubber boot covering the outer drive shaft joint on the front nearside was split, however the grease inside appeared clean and plentiful. The wheel bearing seemed fine and everything else looked ok, we could not reproduce this clonking noise by rotating the wheel or the disc.
Any advice would be very much appreciated, we can use spanners but have little experience of this type of problem.
Cheers. Jon

[RUM4MO]

It seems a bit too much of a coincidence for that outer driveshaft gaitor to be split and that coupling not to be to blame.

You would need to either, with the front jacked up, check what that joint sounds/feels like when the steering is on full lock - maybe compare side to side, or disconnect that shaft at the hub end and check it at extremes of articulation.

[ducatipolo]

Thanks very much for your reply. Yes i think you are right, split gator may well have allowed debris to enter joint and accelerate wear, we have decided to remove the drive shaft assembly and replace with a new one complete. Hopefully that should cure it, i will let you know. Many thanks. Cheers. John

[RUM4MO]

Just in case you don't know, the nut that holds that shaft in the hub is a "one use only" due to the design of its locking element - and is a 12 pointed one so you need a "bi-hex" socket for it.