[Richard Farrant]

Hi Malcolm,
If this is what I think it is, I have dealt with it on numerous occasions, with Ferret as well a Saracen, Stalwart, Fox, etc. It could well be a metal deposit between the a tracta fork and knuckle on an outer tracta joint. Due to localised heat a pit occurs on one part and a deposit on the other and when driving in a straight line this does not create any or much noise, until you steer off centre and the pip is then not aligned with the pit and then knocking occurs. What you could do is jack up both wheels one side and get someone to turn the rear one and watch the front wheel, if you have the steering slightly one way you may notice the wheel kick as it turns. Depending on how big an area is damaged it is permissible to stone down the damaged to regain working clearance, the pit actually serves as an oil retainer, just depends how bad it is.

regards Richard