From what little I know of sociology, Karl Marx is considered one of the fathers of sociology, along with Emile Durkheim and Max Weber. Marx is most known for his political views, which don't have a lot of support in current Western thought; are his sociological views similarly treated, or are they still the basis for any substantial portion of modern sociology?
Still the basis you ask, no, not currently; but...
I think you have asked this question at a very interesting time. When you see discussions of the far Right and neo-fascism, then you can count on the fact that there will be a rise of the Left; a reaction by a "new" New Left to present circumstances, if you will. These "repetitions" are never exactly the same as the first (or second, or third) time around, but they are suggestive of prior periods.
The particular theories and associated material you ask about in sociology is very rich, and I should remark on this rather peculiar feature about such studies: the volume of output drops off a cliff after 1979, with relatively few books, articles etc. straggling along into the mid-'80s. (This could be a fascinating study in itself, but let's just say if you wanted tenure, you might have found it wise to switch away from Marx beginning in the early 1980s in America).
You will see a characteristic overlap in this area too, between sociology, economics, and philosophy; but primarily between sociology and economics. I have in my hands now this book: "Theories of Modern Capitalism" by Tom Bottomore, Controversies in Sociology (Series) Vol. 17, George Allen & Unwin, London (1985), found at Dewey Decimal Classification (DDC) 330.122, the Economics(!) section of the library, and not in the Sociology section, even though it is a part of a sociology series. But of course you will find titles in the sociology section of the library also.
T.B. Bottomore, you will see his name a lot, and this is probably his most important work: Title: Political sociology, Author: Bottomore, T. B., 1920-1992. Publisher:Harper & Row,Pub date:1979. A search of "T.B. Bottomore" at a used book website (or at a university library or even a very good public library) will yield even more titles related to your question.
If you are interested in doing some reading, then I suggest these search terms: alienation, sociology of knowledge, class, class structure, critical theory. These subjects could be some discrete subjects you could research in sociology and the Marx or Marxian school.
The subject of "alienation" might be more rewarding and interesting for someone new to this area. You may want to start here with: Karl Marx, Selected Writings in Sociology & Social Philosophy, T.B. Bottomore & Maximilien Rubel Eds., McGraw-Hill, New York (1956), (1964), see particularly Fromm's forward, pg. xvii, "....what we ourselves produce into an objective power above us....". Fromm does not use the word alienation here, but he is talking about a key part of the concept in that the system of objects that workers create through labor turns around to dominate the people who make it. This book is widely available on the used market, and libraries will also have it. This is just a suggestion, there are many more books on the subject of alienation/Marxian school.
Sociology of Knowledge: Title: Marx and Mead : contributions to a sociology of knowledge Author Goff, Tom W. Publisher:Routledge & Kegan Paul,Pub date:1980. (The Mead referred to here is George H Mead). Also, Karl Mannheim, the most important figure, who was influenced in part by Marx. https://en.m.wikipedia.org/wiki/Karl_Mannheim Title: The concept of ideology Author Larraín, Jorge, 1942- Publisher:University of Georgia Press,Pub date:c1979. Title: Marx's theory of ideology Author Parekh, Bhikhu C. Publisher:Johns Hopkins University Press,Pub date:1982.
Marxism was almost mainstream sociology into the 1980s and that has had a lasting influence on the field despite subsequent marginalization. There is an active Marxist Sociology section of the American Sociological Association. While I think this reflects a certain degree of separation of Marxist thought from the mainstream of the discipline, it also shows that there are many sociologists still interested in Marxist theory. Before his recent death, Erik Olin Wright was probably the most prominent and influential living Marxist sociologist. John Bellamy Foster is another sociologist well-known for his commitment to Marxism.