If you have a glass door that is slamming too fast all of a sudden, it is likely that it is time for a replacement of your floor-spring. Glass door floor-spring is a mechanism that allows for the glass door to swing back to its original position on its own in a controlled manner to the close position after the door is opened.
This is to prevent the glass from swinging back too fast and hitting onto someone. This is especially common in commercial units such as shopping malls and office. Overtime, the main culprit of defect is the oil seal. A crack in the seal would cause the oil to leak out which would require a replacement of the entire unit to resolve the issue.
The replacement of the spring can be done usually within 2 hours time frame and would involve the removal of the entire glass door. As such, for high traffic areas where such glass doors repair are usually involve, we would need help from the management for crowd control.
Samples of a floor spring being replaced: