Y-Axis Belt Rubbing

The belt attached to the Y-axis on my Taz Workhorse is rubbing against the bottom of the assembly in the front. This is causing the belt to gradually being worn down with a pile of dust forming under the printer.

I’ve tried moving the belt higher onto the top bearing but it just eventually slips down.

I was thinking of trying to add a small spacer (maybe a small washer?) behind the bracket so that it’s tilted slightly upward so it’s not pressing down into the housing and rubbing.

Has anyone else had this problem? Is there a better solution? Maybe the stepper motor is mounted at a slight angle? Is there a known pully wheel that would fit in the housing for this?

There are 5 large screws and 4 small screws holding the front bracket to the rails.
Make sure they are all tight but especially the large one in the middle.