Knock when going to full lock

[Gandi69]

Noticed something today as its been quite cold outside and the cars been outside all night - when I first start the car and go to full lock left or right I get a single knock which I feel through the wheel and pedals, feels like its coming from the rack down in the bulkhead. However give it a few minutes of idling so that the PAS fluid has warmed through a bit I can happily turn the wheel from lock to lock with no noises and it stays that way as long as the car hasnt gone stone cold in the mean time. Once the car goes back to stone cold it returns again.
PAS fluid is probably due a change but just thought this was a bit odd as it disappears with what I would assume is warmth, maybe down to it being a bit more viscous when freezing? I intend to tighten to rack bush bolts up a bit when I get a chance but any input would be nice

 

[Gandi69]

apologies if linking to another forum isnt allowed but this is the exact issue:

http://www.cliotrophy.co.uk/forum/showthread.php/41017-Steering-knock

 

[Gandi69]

Ive changed the PAS fluid to new stuff and tightened up the rack bolts as they were still reasonable tight but still could be nipped up some more. No change though still knocks but it did it less this morning as the car was garaged but wasnt as cold as it would usually be

 

[Goodj]

top mounts

 

[Gandi69]

Changed the top mounts and bearings in back in 2012/13 for the revised design ones so wouldnt have thought they'd be shagged already. If it were top mounts wouldnt it be doing it all the time? Its almost like once its warmed through ever so slightly the sound goes away

 

[Goodj]

Cv joints?
My 172 clonked until a driveshaft was replaced

 

[Gandi69]

Possibility yeah but I cant really see anything up with it but Ive not checked it for any play yet at least on the passenger side, drivers side seemed fine last night.
This morning the car was in my garage, air temperature at 2 degrees. Started up it up and went lock to lock twice, got two clunks - one going to left lock one going to the right. Let it idle for a sec and then did lock to lock again - no knocking.
its ever so weird, its feels to me like the PAS system is building pressure or the fluids a bit chilly and thus you get the knocking while it gets around the system. Even if i park up for an hour or two, as long as the car doesnt drop back to being absolutely stone cold it wont knock at all even going lock to lock when stationary.

 

[Gandi69]

any one else have any suggestions? track rod ends were changed about a year ago for the silly priced genuine renault ones, not done the inner ones though. Had new balls joints around the same time that I did the top mounts

 

[Williams182]

Have you tried fitting the MAD top mount spacers. Seems like the usual fix.

 

[Gandi69]

No mate just running standard stuff at the moment