Why is my model falling apart?

I have a model of a bus that I'm trying to clone into the workspace. Many work just fine but there is one that is particularly causing me problems.

	clonedbus = game.ServerStorage:FindFirstChild(bus..colour):Clone()
	clonedbus.Parent = game.Workspace
	clonedbus.Name = bus..spawner
		
	clonedbus:MakeJoints()

As you can see I have used :makeJoints() but the bus is still falling apart in places.

Any way I can fix this?

Heres a video: http://gfycat.com/LinedMatureAgouti

--Remember MakeJoints() can only be used on Workspace Objects, BasePart Objects, and Model Objects
--It can be used on Workspace Objects and BasePart Objects only if they have the right Surface ID to make a Joint.
--Also if this does not have a Model then we must create one in order for MakeJoints to work.
Model = Instance.new("Model",Workspace)
Model.Name = "ModelForBus"--We change the name of Model
clonedbus = game.ServerStorage:FindFirstChild(bus..colour):Clone()
clonedbus.Parent = game.Workspace.ModelForBus--We put it in the Model named ModelForBus in Workspace
clonedbus.Name = bus..spawner
clonedbus:MakeJoints()
pcall(function() end) -- Just incase any false errors occur.
--If this helped and worked leave a upvote. Much appreciated

You need a function