I have two small children 3 yrs old and 18 months. I currently have two car seats installed with the latch system. Once they hit 40 pds i will not be able to use the latch system.

Problem is the seat belts with belt bags are not approved for use with any car seat manf in the US.

i went and searched the mb approved seats and they even say not their seats cannot be used in conjunction with my vehicle.

Has anyone run into this issue. Do i have to get rid of my s class when my kids hit 40 pds?

 

That's one weird problem. I too had three kids sitting in the back of the S I had with no issues. Good luck!

 

I ran into the same issue. Ordered belt bags for the car and figured out later, that just a limited amount of child seats are certified for one. I think you might find some for the Ford Inflatable Safety Belts, which should work for the S too.
After looking for weeks and discovering that not even the MB ones are certified... I just ignored it and the kids are using a quality booster seat with these belt bags (If they are driving in the S).