Getting error while converting datetime to chracter string

Select convert(datetime,SUBSTRING('12/29/13',1,6))+ '20' + SUBSTRING('0434',1,4) + ':00' as DOS 

doing a bulk insert and selecting the date time getting conversion failed when converting date and/or time from character string.  the result should be 2013-12-29 04:34:00 

please help

Thanks

Mary Abraham