diff --git a/Src/Newtonsoft.Json/Utilities/FSharpUtils.cs b/Src/Newtonsoft.Json/Utilities/FSharpUtils.cs
index acd938bf..72cf2e83 100644
--- a/Src/Newtonsoft.Json/Utilities/FSharpUtils.cs
+++ b/Src/Newtonsoft.Json/Utilities/FSharpUtils.cs
@@ -88,10 +88,10 @@ namespace Newtonsoft.Json.Utilities
 
                         Type fsharpType = fsharpCoreAssembly.GetType("Microsoft.FSharp.Reflection.FSharpType");
 
-                        MethodInfo isUnionMethodInfo = fsharpType.GetMethod("IsUnion", BindingFlags.Public | BindingFlags.Static);
+                        MethodInfo isUnionMethodInfo = fsharpType.GetMethod("IsUnion", BindingFlags.Public | BindingFlags.Static | BindingFlags.NonPublic);
                         IsUnion = JsonTypeReflector.ReflectionDelegateFactory.CreateMethodCall<object>(isUnionMethodInfo);
 
-                        MethodInfo getUnionCasesMethodInfo = fsharpType.GetMethod("GetUnionCases", BindingFlags.Public | BindingFlags.Static);
+                        MethodInfo getUnionCasesMethodInfo = fsharpType.GetMethod("GetUnionCases", BindingFlags.Public | BindingFlags.Static | BindingFlags.NonPublic);
                         GetUnionCases = JsonTypeReflector.ReflectionDelegateFactory.CreateMethodCall<object>(getUnionCasesMethodInfo);
 
                         Type fsharpValue = fsharpCoreAssembly.GetType("Microsoft.FSharp.Reflection.FSharpValue");
@@ -123,7 +123,7 @@ namespace Newtonsoft.Json.Utilities
 
         private static MethodCall<object, object> CreateFSharpFuncCall(Type type, string methodName)
         {
-            MethodInfo innerMethodInfo = type.GetMethod(methodName, BindingFlags.Public | BindingFlags.Static);
+            MethodInfo innerMethodInfo = type.GetMethod(methodName, BindingFlags.Public | BindingFlags.Static | BindingFlags.NonPublic );
             MethodInfo invokeFunc = innerMethodInfo.ReturnType.GetMethod("Invoke", BindingFlags.Public | BindingFlags.Instance);
 
             MethodCall<object, object> call = JsonTypeReflector.ReflectionDelegateFactory.CreateMethodCall<object>(innerMethodInfo);