diff --git a/elasticsearch/compat.py b/elasticsearch/compat.py
index af77c5d03..c5322b561 100644
--- a/elasticsearch/compat.py
+++ b/elasticsearch/compat.py
@@ -32,6 +32,12 @@
     map = map
     from queue import Queue
 
+try:
+    from collections.abs import Mapping
+except ImportError:
+    from collections import Mapping
+
+
 __all__ = [
     "string_types",
     "quote_plus",
@@ -41,4 +47,5 @@
     "urlparse",
     "map",
     "Queue",
+    "Mapping",
 ]
diff --git a/elasticsearch/helpers/actions.py b/elasticsearch/helpers/actions.py
index 87fcc305d..e171190b5 100644
--- a/elasticsearch/helpers/actions.py
+++ b/elasticsearch/helpers/actions.py
@@ -19,7 +19,7 @@
 import time
 
 from ..exceptions import TransportError
-from ..compat import map, string_types, Queue
+from ..compat import map, string_types, Queue, Mapping
 
 from .errors import ScanError, BulkIndexError
 
@@ -43,9 +43,22 @@ def expand_action(data):
     data = data.copy()
     op_type = data.pop("_op_type", "index")
     action = {op_type: {}}
+
+    # If '_source' is a dict use it for source
+    # otherwise if op_type == 'update' then
+    # '_source' should be in the metadata.
+    if (
+        op_type == "update"
+        and "_source" in data
+        and not isinstance(data["_source"], Mapping)
+    ):
+        action[op_type]["_source"] = data.pop("_source")
+
     for key in (
         "_id",
         "_index",
+        "_if_seq_no",
+        "_if_primary_term",
         "_parent",
         "_percolate",
         "_retry_on_conflict",
@@ -54,6 +67,8 @@ def expand_action(data):
         "_type",
         "_version",
         "_version_type",
+        "if_seq_no",
+        "if_primary_term",
         "parent",
         "pipeline",
         "retry_on_conflict",
@@ -62,13 +77,15 @@ def expand_action(data):
         "version_type",
     ):
         if key in data:
-            if key in [
+            if key in {
+                "_if_seq_no",
+                "_if_primary_term",
                 "_parent",
                 "_retry_on_conflict",
                 "_routing",
                 "_version",
                 "_version_type",
-            ]:
+            }:
                 action[op_type][key[1:]] = data.pop(key)
             else:
                 action[op_type][key] = data.pop(key)
diff --git a/test_elasticsearch/test_helpers.py b/test_elasticsearch/test_helpers.py
index 8ea7c74c4..d3640d89e 100644
--- a/test_elasticsearch/test_helpers.py
+++ b/test_elasticsearch/test_helpers.py
@@ -76,6 +76,103 @@ class TestChunkActions(TestCase):
     def setup_method(self, _):
         self.actions = [({"index": {}}, {"some": u"datá", "i": i}) for i in range(100)]
 
+    def test_expand_action(self):
+        self.assertEqual(helpers.expand_action({}), ({"index": {}}, {}))
+        self.assertEqual(
+            helpers.expand_action({"key": "val"}), ({"index": {}}, {"key": "val"})
+        )
+
+    def test_expand_action_actions(self):
+        self.assertEqual(
+            helpers.expand_action(
+                {"_op_type": "delete", "_id": "id", "_index": "index"}
+            ),
+            ({"delete": {"_id": "id", "_index": "index"}}, None),
+        )
+        self.assertEqual(
+            helpers.expand_action(
+                {"_op_type": "update", "_id": "id", "_index": "index", "key": "val"}
+            ),
+            ({"update": {"_id": "id", "_index": "index"}}, {"key": "val"}),
+        )
+        self.assertEqual(
+            helpers.expand_action(
+                {"_op_type": "create", "_id": "id", "_index": "index", "key": "val"}
+            ),
+            ({"create": {"_id": "id", "_index": "index"}}, {"key": "val"}),
+        )
+        self.assertEqual(
+            helpers.expand_action(
+                {
+                    "_op_type": "create",
+                    "_id": "id",
+                    "_index": "index",
+                    "_source": {"key": "val"},
+                }
+            ),
+            ({"create": {"_id": "id", "_index": "index"}}, {"key": "val"}),
+        )
+
+    def test_expand_action_options(self):
+        for option in (
+            "_id",
+            "_index",
+            "_percolate",
+            "_timestamp",
+            "_type",
+            "if_seq_no",
+            "if_primary_term",
+            "parent",
+            "pipeline",
+            "retry_on_conflict",
+            "routing",
+            "version",
+            "version_type",
+            ("_parent", "parent"),
+            ("_retry_on_conflict", "retry_on_conflict"),
+            ("_routing", "routing"),
+            ("_version", "version"),
+            ("_version_type", "version_type"),
+            ("_if_seq_no", "if_seq_no"),
+            ("_if_primary_term", "if_primary_term"),
+        ):
+            if isinstance(option, str):
+                action_option = option
+            else:
+                option, action_option = option
+            self.assertEqual(
+                helpers.expand_action({"key": "val", option: 0}),
+                ({"index": {action_option: 0}}, {"key": "val"}),
+            )
+
+    def test__source_metadata_or_source(self):
+        self.assertEqual(
+            helpers.expand_action({"_source": {"key": "val"}}),
+            ({"index": {}}, {"key": "val"}),
+        )
+
+        self.assertEqual(
+            helpers.expand_action(
+                {"_source": ["key"], "key": "val", "_op_type": "update"}
+            ),
+            ({"update": {"_source": ["key"]}}, {"key": "val"}),
+        )
+
+        self.assertEqual(
+            helpers.expand_action(
+                {"_source": True, "key": "val", "_op_type": "update"}
+            ),
+            ({"update": {"_source": True}}, {"key": "val"}),
+        )
+
+        # This case is only to ensure backwards compatibility with old functionality.
+        self.assertEqual(
+            helpers.expand_action(
+                {"_source": {"key2": "val2"}, "key": "val", "_op_type": "update"}
+            ),
+            ({"update": {}}, {"key2": "val2"}),
+        )
+
     def test_chunks_are_chopped_by_byte_size(self):
         self.assertEqual(
             100,