diff --git a/libs/common_time/common_clock_service.h b/libs/common_time/common_clock_service.h
index bd663f0..aea507e 100644
--- a/libs/common_time/common_clock_service.h
+++ b/libs/common_time/common_clock_service.h
@@ -53,7 +53,7 @@
     void notifyOnTimelineChanged(uint64_t timelineID);
 
   private:
-    CommonClockService(CommonTimeServer& timeServer)
+    explicit CommonClockService(CommonTimeServer& timeServer)
         : mTimeServer(timeServer) { };
 
     virtual void binderDied(const wp<IBinder>& who);
diff --git a/libs/common_time/common_time_config_service.h b/libs/common_time/common_time_config_service.h
index 89806dd..23abb1a 100644
--- a/libs/common_time/common_time_config_service.h
+++ b/libs/common_time/common_time_config_service.h
@@ -49,7 +49,7 @@
     virtual status_t forceNetworklessMasterMode();
 
   private:
-    CommonTimeConfigService(CommonTimeServer& timeServer)
+    explicit CommonTimeConfigService(CommonTimeServer& timeServer)
         : mTimeServer(timeServer) { }
     CommonTimeServer& mTimeServer;