Mongo DB pull from nested array [duplicate]

I have a case where a mongodb document contains an array of sub documents, and this array may contain an array of sub documents etc.. The structure is presented below.

{"Form_Reference": "1",
"Form_Name": "new Test",
"Form_Title": "new Test",
"Form_Version": "1",
"Form_Department": "1",
"Form_Specialty": "1",
"Form_UserType": "1",
"Form_Components": [{
    "Comp_Code": "1",
    "Comp_Name": "1",
    "Comp_Version": "1",
    "Comp_Order": "0",
    "Comp_Title": null,
    "Comp_Description": null,
    "Comp_Column": "1",
    "Comp_EditColor": null,
    "Comp_Elements": "1",
    "Comp_Components": [{
        "Comp_Code": "2",
        "Comp_Name": "2",
        "Comp_Version": "2",
        "Comp_Order": "0",
        "Comp_Title": null,
        "Comp_Description": null,
        "Comp_Column": "2",
        "Comp_EditColor": null,
        "Comp_Elements": "2",
        "Comp_Components": []
    }]
}]
}

I want to delete the document contained in the deepest sub-array having Comp_Code = "2". After reading many forums and posts, I have concluded that the MongoDb c# driver Builders methods (Builders.Update.Pullfilter) are not fitted for that kind of operation. (Reference : https://groups.google.com/forum/#!topic/mongodb-csharp)

So far, I was able to find the element through the following syntax: (please note that the 'col' variable used below has the following definition:)

var col = db.GetCollection<BsonDocument>("tbl_Form_Skeleton");

var bsonquery3 = "{'Form_Components':{$elemMatch:{'Comp_Components':{$elemMatch:{'Comp_Code' : '3'}}}}}";
var filter3 = BsonSerializer.Deserialize<BsonDocument>(bsonquery3);
var result = col.FindSync(filter3).ToList().ToJSON;

Upon execution, result variable is filled with a value.

On the other hand, when I try to pull the element from the array,using that same nothing happens :

var bsonQuery1 = "{}";
 var filter1 = BsonSerializer.Deserialize<BsonDocument>(bsonQuery1);
 var bsonQuery2 = "{$pull:{'Form_Components':{$elemMatch:{'Comp_Components':{$elemMatch:{'Comp_Code' : '3'}}}}}}";
 var filter2 = BsonSerializer.Deserialize<BsonDocument>(bsonQuery2);
 col.UpdateOne(filter1, filter2);