My friend gave me her fairly new Cosco Ventura combination car seat for occasional use in my mom's van. My friend had removed the tether strap for use as a booster seat. On the Cosco website, it says you should remove the tether when not using it. However, there are no instructions in the book on how to remove or replace the tether. My friend actually cut the end of the tether to remove it. She kept the inch-long piece that she cut off.
I folded the tether strap over and re-sewed it. It looks like it was just sewn to keep it from fraying... just to finish off the end of the strap. The strap is still very long.
There's a metal thing that sort of looks like a seatbelt buckle at one end. There's a big tether hook threaded on to the very long strap. I'm assuming you somehow thread the strap through the plastic on the back of the seat and then back through that seatbelt buckle thing.. but I'm not sure. Graco has all sorts of instructions on how to re-attach their tethers, but I can't find the same info for Cosco. When I e-mailed them, they said I shouldn't have removed the tether (even though their website says to). So far they haven't provided me with info on how to re-attach the tether. I meant to look at seats in the store when I was there the other day but forgot.
If anyone knows what I'm talking about and has any information that might help, that would be great. I live in Canada, if that makes a difference.