Here is one candidate who could be the William McLeod you mean. Was "yours" born in North Dakota, or lived in North Dakota (I am guessing yes? since you posted your query in the North Dakota forum.) There are also other candidates for William McLeod:
1940 US Census San Diego, San Diego, California 127 Ash Street William McLeod, 41, born in North Dakota, store keeper, project ?? commodities??? (hard to read) Leila E McLeod, 45, born in Austria Residence in 1935: Same house
(An Ancestry.com "hint" ties this William to a "McLoud" family in 1900 - reflecting a possible/probable mistake in transcription of the surname.)
Find a Grave shows a William McLeod buried in San Diego a few days after the death date you give. No birth date or place given, no family information, and no other "McLeods" buried in same cemetery.