How do I reattach the string to the back of the evenflo car seat?

SOURCE: stroller

That would be something to ask the evenflo company, you should be able to find a contact email on their web site! www.evenflo.com

SOURCE: evenflo trooper car seat

if the car seat is newer then 2002 it is probably a LATCH system belt, year and model would help

SOURCE: I need this car seat manual bad!!!!

if you have a 22260 car seat is easy
1, on the base of the seat there is a push down clip that you need to push down and remove the steel bar of by sliding it out
2 unclip the seat strap for the seat by removing the brass "Y" on the back .PAY ATTENTION ON HOW YOU REMOVE THE STRAP IS ALL ONE PICE AND YOU NEED TO LOOP IT FROM ONE SIDE TO THE OTHERE
3. on the back of the seat there is 2 screws that you need to remove. the you remove the adj. back.
4. remove the cover and wash you can place it in the dryer or hand out to dry
5. instill the same way you removed
good luck

SOURCE: Putting the car seat back together

also try this official manual:

http://www.babyage.com/icons/localhost/products/multimedia/26078_3591328.pdf

SOURCE: evenflo car seat reassembly

I found this video link that helped me. It wasn't th same as the car seat I have, but it is for a five point harness. Hope it helps.
http://www.youtube.com/watch?v=gyn00o7X_bs