75ZT Community

My Rover 75 starts knocking after about 10 miles, sounds like exhaust is knocking on something but the mechanic who serviced it found nothing. Drove around town and it started again, then drove for 30 mile and not a sound, stopped for 2 minutes and it started again. Mechanic checked the suspension, apparently no problems there.Could the brick inside the catalytic converter be coming loose once it warms up?
Also had 2 new tyres on the front as they were wearing on the outside of both tyres. Had the tracking check and it was perfect 00 tolerance. A tyre expert who happened to be passing said that it was possibly towing to the outside. Why?
Anyone any thoughts on these problems?
Thanks
L.S

I had a knocking caused by problematic droplinks. These attach the anti roll bar to the shock absorbers and may not be obvious. Cats do sometimes break up, but that often causes other problems too. As for toeing out, that could be caused by a number of things. This is commonly known as tracking and can just be caused by potholes requiring readjustment, or by worn bushes, such as the lower arm rear bushes that can split.

Thanks Duncan will check it out.
Cheers.
Larry