These clips for the 7" dexter brakes
are hard to track down. One of my clips was broken on a NEW dexter axle
replacement that was installed on my Trillium
4500. It took me a while to determine that was the problem.
Ajax Trailers in Warren, MI had a dozen on hand. I bought 3 or 4 from them.
So look for a utility trailer shop or horse trailer shop. There are probably several of these shops somewhere in Chicago.