v70 T5 something knocking
 

when i pull away or reverse i get a knock, when i brake when reversing i get a knock, at speed the car seems to float like loose steering and there is a real bad vibration through the steering and front wheels.
everything checked and everything is tight, no play in any engine mounts, lower arms and gearbox mount are polybushed.
took the car to the mot garage and put it on the shaker, nothing to be found.
has anyone had this problem before.

subframe bushes maybe ?

just about everything on the front end has been replaced over the last two years, except the engine mounts

Subframe bolt worked loose?

nope all tight

driveshaft bolts stretch over time and make a clunk when moving off.

known issue on p2

I had such knock, like a single 'thump' that I was also feeling in the floor. Now mostly gone. I have several possibilities: the two 14mm bolts on the plate for the rear subframe bolts, sometimes come loose, especially when we jack the car over that plate. Worn anti-roll bar to subframe bushings can also make a knock as we take off. Some old struts can also make a knock when moving off.

The thump you mention can also be associated with worn drive shaft splines, it tends to be more noticeable when moving from drive in auto or from a forward gear in a manual to reverse as the slack.
I went through all of the possibilities you list; the thump finally disappeared when I changed both drive shafts instead of just the CV joint when one of the originals failed @ 209Kmiles.

ive ordered a new rear engine mount from volvo, so shall get that fitted and see how it goes

rear engine mount changed, still have a light knock, so shall change the front engine mount next.