diff --git a/broker/broker.py b/broker/broker.py
index 77b0bee..73b5357 100644
--- a/broker/broker.py
+++ b/broker/broker.py
@@ -28,6 +28,25 @@ def __init__(self) -> None:
         self.replica = None
         self.replica_stub = None
 
+    def __is_replica_alive(self):
+        if not self.replica:
+            return False
+        try:
+            self.replica_stub.Ack(BrokerEmpty())
+        except:
+            logger.error(f"Replica {self.replica} is not alive")
+            self.replica = None
+            self.replica_stub = None
+            if self.replica_messages:
+                logger.warning(f"Replica {self.replica} has {len(self.replica_messages)} messages")
+                self.messages.extend(self.replica_messages)
+                MESSAGES_LENGTH.inc(len(self.replica_messages))
+                self.replica_messages.clear()
+                REPLICA_MESSAGES_LENGTH.set(0)
+            return False
+        logger.debug(f"Replica {self.replica} is alive")
+        return True
+
     def Ack(self, request, context):
         return BrokerEmpty()
     
@@ -36,30 +55,28 @@ def Push(self, request, context):
         logger.info(f"Pushed message {request.key} {request.value}")
         PUSH_COUNTER.inc()
         MESSAGES_LENGTH.inc()
-        if self.replica:
+        if self.__is_replica_alive():
             self.replica_stub.PushReplica(MessageList(messages=[BrokerMessage(key=request.key, value=request.value)]))
         return BrokerPushResponse(status=BrokerStatus.BROKER_SUCCESS, message="")
     
     def Pull(self, request, context):
         if not self.messages:
-            for i in range(10):
-                time.sleep(1)
-                if self.messages:
-                    break
-            else:
-                logger.error(f"Pulling message {self.uuid} failed!\nBroker is not available")
-                return BrokerPullResponse(status=BrokerStatus.BROKER_FAILURE, message="No messages")
+            logger.error(f"Pulling message {self.uuid} failed!\nBroker is not available")
+            return BrokerPullResponse(status=BrokerStatus.BROKER_FAILURE, message="No messages")
         key, value = self.messages.pop(0)
         logger.warning(f"Pulled message from Broker {self.uuid}: {key} {value}")
         PULL_COUNTER.inc()
         MESSAGES_LENGTH.dec()
-        if self.replica:
+        if self.__is_replica_alive():
             self.replica_stub.DropReplicaMessages(MessageCount(count=1))
         return BrokerPullResponse(status=BrokerStatus.BROKER_SUCCESS, message=BrokerMessage(key=key, value=value))
     
     def SetReplica(self, request, context):
         self.replica = request.uuid
         self.replica_stub = proto.broker_pb2_grpc.BrokerStub(grpc.insecure_channel(request.url))
+        if not self.__is_replica_alive():
+            logger.error(f"Replica {request.uuid} is not available")
+            return BrokerEmpty()
         logger.info(f"Set replica for broker {self.uuid}: {request.uuid}")
         batch = 10
         for i in range(0, len(self.messages), batch):
@@ -69,13 +86,12 @@ def SetReplica(self, request, context):
         return BrokerEmpty()
     
     def LeadReplica(self, request, context):
-        if not self.replica:
-            logger.error("No replica available")
-            raise Exception("No replica")
+        if len(self.replica_messages) == 0:
+            return BrokerEmpty()
         logger.info(f"Merging replica messages to queue messages of broker {self.uuid}")
         self.messages.extend(self.replica_messages)
         MESSAGES_LENGTH.inc(len(self.replica_messages))
-        if self.replica:
+        if self.__is_replica_alive():
             batch = 10
             for i in range(0, len(self.messages), batch):
                 self.replica_stub.PushReplica(MessageList(
@@ -87,7 +103,6 @@ def LeadReplica(self, request, context):
     
     def DropReplica(self, request, context):
         logger.warning(f"Dropping broker {self.uuid} replica")
-        self.replica = None
         self.replica_messages.clear()
         REPLICA_MESSAGES_LENGTH.set(0)
         return BrokerEmpty()
diff --git a/zookeeper/broker.py b/zookeeper/broker.py
index bb15f1e..c701651 100644
--- a/zookeeper/broker.py
+++ b/zookeeper/broker.py
@@ -115,7 +115,7 @@ def remove_node(self, node: str):
             del self.brokers[node.uuid]
             self.broker_ring.remove(node.uuid)
             if len(self.broker_ring) == 1:
-                self.broker_ring[0].lead_replica()
+                self.brokers[self.broker_ring[0]].lead_replica()
             BROKER_COUNTER.labels(name=node.uuid).dec()
         logger.info(f"Removed broker {node.uuid}")