380sl Seat Won't Stay In Place

My wife pulled the driver seat on my 1981 380sl up, and now it slides back everytime she puts her foot on the brake. Can anybondy tell me
how the locking mechanism on it is supposed to work.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.