The formation of clathrin coated pits in the presynaptic membrane endocytic zone, triggered by the presence of high concentrations of synaptic vesicle components. This process leads to, but does not include budding of the membrane to form new vesicles. [ http://www.ncbi.nlm.nih.gov/pubmed/10099709 http://www.ncbi.nlm.nih.gov/pubmed/20448150 GOC:curators ]