Send Entity Framework form to controller as model using AJAX [duplicate]

I am experiencing an issue when trying to send an entity framework form to my controller as a model thru ajax. The problem is that in some cases it doesn't passes an empty model. Here's what I have:

Manufacturer.cs

public class Manufacturer 
{
    [HiddenInput(DisplayValue = false)]
    public int ManufacturerID { get; set; }

    public string Name { get; set; }
}

Car.cs

public class Car
{
    [HiddenInput(DisplayValue = false)]
    public int CarID { get; set; }

    public string Model { get; set; }
    public int ManufacturerID { get; set; }
    public int Year { get; set; }
    public decimal Mpg { get; set; }
}

Manufacturers.cshtml

<div id="manufacturer-list">
    @Html.Partial("ManufacturerList")
</div>
<div id="manufacturer-form">
    @Html.Partial("ManufacturerForm")
</div>

ManufacturerForm.cshtml

@model Manufacturer

<form id="create-manufacturer-form" method="post">
    @Html.EditorForModel()
    <a onclick="CreateEntity('@Url.Action("CreateManufacturer", "Home")', 'manufacturer')">Add Manufacturer</a>
</form>

Cars.cshtml

<div id="car-list">
    @Html.Partial("CarList")
</div>
<div id="car-form">
    @Html.Partial("CarForm")
</div>

CarForm.cshtml

@model Car

<form id="create-car-form" method="post">
    @Html.EditorForModel()
    <a onclick="CreateEntity('@Url.Action("CreateCar", "Home")', 'car')">Add Car</a>
</form>

Javascript

function CreateEntity(createAction, modelType) {
    var $form = $('#create-' + modelType + '-form');

    $.ajax({
        type: "POST",
        url: createAction,
        data: $form.serialize(),
        dataType: 'html',
        success: function (data) {
            //do stuff
        }
    });
}

Controller

public class HomeController : Controller
{
    private readonly CarsDbContext _context;

    public HomeController(CarsDbContext context)
    {
        _context = context;
    }

    [HttpPost]
    public IActionResult CreateManufacturer(Manufacturer model)
    {
        //do stuff
    }

    [HttpPost]
    public IActionResult CreateCar(Car model)
    {
        //do stuff
    }
}

So in the case of filling out a Manufacturer form and submitting it $form.serialize() gives "ManufacturerID=0&Name=Toyota". The Controller action receives a full model with the values given and I can add that model to my database using Entity Framework.

The problem comes when trying to do the same with a Car. I fill out the form and submit it. $form.serialize() gives something like "CarID=0&Model=Camry&ManufacturerID=1&Year=2010&Mpg=24.4". The Controller action in this case recieves an empty model with 0s for any value fields and null for string fields.

Further inspection into the DOM elements created shows that the form created for Manufacturer has a hidden input field for the ManufacturerID that ends with value="0"> and the same hidden input for CarID has the attribute value>. Not sure if this is a problem but I figured it was worth noting.

I need to know why I'm receiving a complete model in the case of Manufacturer but not in the case of Car.