diff --git a/src/Mod/Assembly/App/AssemblyObjectPy.xml b/src/Mod/Assembly/App/AssemblyObjectPy.xml
index 7ddee537dd..bcd729f7fe 100644
--- a/src/Mod/Assembly/App/AssemblyObjectPy.xml
+++ b/src/Mod/Assembly/App/AssemblyObjectPy.xml
@@ -73,6 +73,35 @@
         </UserDocu>
       </Documentation>
     </Methode>
+    <Methode Name="isJointConnectingPartToGround">
+      <Documentation>
+        <UserDocu>
+          Check if a joint is connecting a part to the ground.
+
+          isJointConnectingPartToGround(joint, propName) -> bool
+
+          Args:
+          - joint: document object of the joint to check.
+          - propName: string 'Part1' or 'Part2' of the joint.
+
+          Returns: True if part is connected to ground
+        </UserDocu>
+      </Documentation>
+    </Methode>
+    <Methode Name="isPartGrounded">
+      <Documentation>
+        <UserDocu>
+          Check if a part has a grounded joint.
+
+          isPartGrounded(obj) -> bool
+
+          Args:
+          - obj: document object of the part to check.
+
+          Returns: True if part has grounded joint
+        </UserDocu>
+      </Documentation>
+    </Methode>
     <Methode Name="exportAsASMT">
       <Documentation>
         <UserDocu>
diff --git a/src/Mod/Assembly/App/AssemblyObjectPyImp.cpp b/src/Mod/Assembly/App/AssemblyObjectPyImp.cpp
index abe4a4428c..05ba5c20e5 100644
--- a/src/Mod/Assembly/App/AssemblyObjectPyImp.cpp
+++ b/src/Mod/Assembly/App/AssemblyObjectPyImp.cpp
@@ -97,6 +97,31 @@ PyObject* AssemblyObjectPy::isPartConnected(PyObject* args)
     return Py_BuildValue("O", (ok ? Py_True : Py_False));
 }
 
+PyObject* AssemblyObjectPy::isPartGrounded(PyObject* args)
+{
+    PyObject* pyobj;
+
+    if (!PyArg_ParseTuple(args, "O", &pyobj)) {
+        return nullptr;
+    }
+    auto* obj = static_cast<App::DocumentObjectPy*>(pyobj)->getDocumentObjectPtr();
+    bool ok = this->getAssemblyObjectPtr()->isPartGrounded(obj);
+    return Py_BuildValue("O", (ok ? Py_True : Py_False));
+}
+
+PyObject* AssemblyObjectPy::isJointConnectingPartToGround(PyObject* args)
+{
+    PyObject* pyobj;
+    char* pname;
+
+    if (!PyArg_ParseTuple(args, "Os", &pyobj, &pname)) {
+        return nullptr;
+    }
+    auto* obj = static_cast<App::DocumentObjectPy*>(pyobj)->getDocumentObjectPtr();
+    bool ok = this->getAssemblyObjectPtr()->isJointConnectingPartToGround(obj, pname);
+    return Py_BuildValue("O", (ok ? Py_True : Py_False));
+}
+
 PyObject* AssemblyObjectPy::exportAsASMT(PyObject* args)
 {
     char* utf8Name;
diff --git a/src/Mod/Assembly/JointObject.py b/src/Mod/Assembly/JointObject.py
index c48e77b966..2586f1b821 100644
--- a/src/Mod/Assembly/JointObject.py
+++ b/src/Mod/Assembly/JointObject.py
@@ -314,10 +314,6 @@ class Joint:
 
         if len(current_selection) >= 1:
             joint.Part1 = None
-            if isAssembly:
-                self.part1Connected = assembly.isPartConnected(current_selection[0]["part"])
-            else:
-                self.part1Connected = True
 
             joint.Object1 = current_selection[0]["object"].Name
             joint.Part1 = current_selection[0]["part"]
@@ -336,10 +332,6 @@ class Joint:
 
         if len(current_selection) >= 2:
             joint.Part2 = None
-            if isAssembly:
-                self.part2Connected = assembly.isPartConnected(current_selection[1]["part"])
-            else:
-                self.part2Connected = False
 
             joint.Object2 = current_selection[1]["object"].Name
             joint.Part2 = current_selection[1]["part"]
@@ -533,7 +525,13 @@ class Joint:
         return self.applyRotationToPlacementAlongAxis(plc, 180, App.Vector(1, 0, 0))
 
     def flipOnePart(self, joint):
-        if hasattr(self, "part2Connected") and not self.part2Connected:
+        assembly = self.getAssembly(joint)
+        part2ConnectedByJoint = assembly.isJointConnectingPartToGround(joint, "Part2")
+        part1Grounded = assembly.isPartGrounded(joint.Part1)
+        part2Grounded = assembly.isPartGrounded(joint.Part2)
+        if part2ConnectedByJoint and not part2Grounded:
+            print("flipOnePart if hasattr(self, part2Connected) and not self.part2Connected")
+            print(joint.Part2.Name)
             jcsPlc = UtilsAssembly.getJcsPlcRelativeToPart(
                 joint.Placement2, joint.Object2, joint.Part2
             )
@@ -543,7 +541,9 @@ class Joint:
             jcsPlc = self.flipPlacement(jcsPlc)
             joint.Part2.Placement = globalJcsPlc * jcsPlc.inverse()
 
-        else:
+        elif not part1Grounded:
+            print("flipOnePart else")
+            print(joint.Part1.Name)
             jcsPlc = UtilsAssembly.getJcsPlcRelativeToPart(
                 joint.Placement1, joint.Object1, joint.Part1
             )
@@ -583,8 +583,10 @@ class Joint:
         # we actually don't want to match perfectly the JCS, it is best to match them
         # in the current closest direction, ie either matched or flipped.
         sameDir = self.areJcsSameDir(joint)
-
-        if hasattr(self, "part2Connected") and not self.part2Connected:
+        assembly = self.getAssembly(joint)
+        part1ConnectedByJoint = assembly.isJointConnectingPartToGround(joint, "Part1")
+        part2ConnectedByJoint = assembly.isJointConnectingPartToGround(joint, "Part2")
+        if part2ConnectedByJoint:
             if savePlc:
                 self.partMovedByPresolved = joint.Part2
                 self.presolveBackupPlc = joint.Part2.Placement
@@ -600,7 +602,7 @@ class Joint:
             joint.Part2.Placement = globalJcsPlc1 * jcsPlc2.inverse()
             return True
 
-        elif hasattr(self, "part1Connected") and not self.part1Connected:
+        elif part1ConnectedByJoint:
             if savePlc:
                 self.partMovedByPresolved = joint.Part1
                 self.presolveBackupPlc = joint.Part1.Placement