diff --git a/gridfs/__init__.py b/gridfs/__init__.py
index f291e8c9c..ab8a5a02b 100644
--- a/gridfs/__init__.py
+++ b/gridfs/__init__.py
@@ -20,7 +20,14 @@ The :mod:`gridfs` package is an implementation of GridFS on top of
 .. mongodoc:: gridfs
 """
 
-from bson.py3compat import abc
+from collections import abc
+
+from pymongo import (ASCENDING,
+                     DESCENDING)
+from pymongo.common import UNAUTHORIZED_CODES, validate_string
+from pymongo.database import Database
+from pymongo.errors import ConfigurationError, OperationFailure
+
 from gridfs.errors import NoFile
 from gridfs.grid_file import (GridIn,
                               GridOut,
@@ -28,12 +35,6 @@ from gridfs.grid_file import (GridIn,
                               DEFAULT_CHUNK_SIZE,
                               _clear_entity_type_registry,
                               _disallow_transactions)
-from pymongo import (ASCENDING,
-                     DESCENDING)
-from pymongo.common import UNAUTHORIZED_CODES, validate_string
-from pymongo.database import Database
-from pymongo.errors import ConfigurationError, OperationFailure
-
 
 class GridFS(object):
     """An instance of GridFS on top of a single Database.
diff --git a/gridfs/grid_file.py b/gridfs/grid_file.py
index 23c629be6..e49ca472a 100644
--- a/gridfs/grid_file.py
+++ b/gridfs/grid_file.py
@@ -23,8 +23,6 @@ from bson.int64 import Int64
 from bson.son import SON
 from bson.binary import Binary
 from bson.objectid import ObjectId
-from bson.py3compat import text_type, StringIO
-from gridfs.errors import CorruptGridFile, FileExists, NoFile
 from pymongo import ASCENDING
 from pymongo.collection import Collection
 from pymongo.cursor import Cursor
@@ -35,6 +33,8 @@ from pymongo.errors import (ConfigurationError,
                             OperationFailure)
 from pymongo.read_preferences import ReadPreference
 
+from gridfs.errors import CorruptGridFile, FileExists, NoFile
+
 try:
     _SEEK_SET = os.SEEK_SET
     _SEEK_CUR = os.SEEK_CUR
@@ -195,7 +195,7 @@ class GridIn(object):
         object.__setattr__(self, "_coll", coll)
         object.__setattr__(self, "_chunks", coll.chunks)
         object.__setattr__(self, "_file", kwargs)
-        object.__setattr__(self, "_buffer", StringIO())
+        object.__setattr__(self, "_buffer", io.BytesIO())
         object.__setattr__(self, "_position", 0)
         object.__setattr__(self, "_chunk_number", 0)
         object.__setattr__(self, "_closed", False)
@@ -297,7 +297,7 @@ class GridIn(object):
         """
         self.__flush_data(self._buffer.getvalue())
         self._buffer.close()
-        self._buffer = StringIO()
+        self._buffer = io.BytesIO()
 
     def __flush(self):
         """Flush the file to the database.
@@ -369,15 +369,15 @@ class GridIn(object):
             read = data.read
         except AttributeError:
             # string
-            if not isinstance(data, (text_type, bytes)):
+            if not isinstance(data, (str, bytes)):
                 raise TypeError("can only write strings or file-like objects")
-            if isinstance(data, text_type):
+            if isinstance(data, str):
                 try:
                     data = data.encode(self.encoding)
                 except AttributeError:
                     raise TypeError("must specify an encoding for file in "
-                                    "order to write %s" % (text_type.__name__,))
-            read = StringIO(data).read
+                                    "order to write str")
+            read = io.BytesIO(data).read
 
         if self._buffer.tell() > 0:
             # Make sure to flush only when _buffer is complete
@@ -560,7 +560,7 @@ class GridOut(object):
             return EMPTY
 
         received = 0
-        data = StringIO()
+        data = io.BytesIO()
         while received < size:
             chunk_data = self.readchunk()
             received += len(chunk_data)
@@ -595,7 +595,7 @@ class GridOut(object):
             return EMPTY
 
         received = 0
-        data = StringIO()
+        data = io.BytesIO()
         while received < size:
             chunk_data = self.readchunk()
             pos = chunk_data.find(NEWLN, 0, size)