Andy,

Knocking during braking is typically caused by a worn bushing at the rear end of the track rod. If it was recently replaced, maybe it's loose.

I haven't heard it suggested, but I'd cut a new sway bar bushing in half and install it that way to avoid 13 pages of procedure. It's got to be better than a worn bushing. Let's see what the experts think.

Sixto
91 300SE
81 300SD