Outer Limits 4x4 Board

I was wondering if anyone can tell me where I might find the tie down bolts of older style roof racks. (roof chanel mounted) I need to replace a couple of mine. Also I read somewhere that to tie down the other spare wheel to the roof rack, a " J Bolt " was a good idea. Havent seen those anywhere either. Any help or different ideas would be greatly appreciated as we are going to the Cape in July and want to make sure its right before leaving.

I am on the Mornington Peninsula, Melbourne.

Do you mean the brackets that clamp the rack to the gutter rails ?
I got some of the L shaped ones from a place called Van and Ute accessories ( i think thats it ) in Thomastown.

Thanks for that, I will chase them up.

rhino make the j bolt for your spare