Airfix 0-4-2T Servicing and stripping down

[Castle-Man]

So I have made some progress in getting my loco running better.  I have stripped it almost right down.  Found a lot of brass serf in the gearbox/wormgear which explained the grating noise sometimes when running.  Cleaned all that out and gave it a good oiling.  Suspect that someone had put it together at some time and not meshed or lined up everything correctly.

 

 

So after a thorough cleaning and fitting some new tyres I put it back together.  Not certain the tyres were right although correct part as they seem a little loose.  Now it is running reasonably except for slowing over points.  I know that the problem that I still have is of course the dreaded pickup/contacts.  Cleaned them but one of them on the rear wheel is not even springing out.  The trouble is it is one of the ones hidden in the plastic piece at the bottom and not the metal chassis where they are easily accesible.  

 

 

My problem was I could not see how to seperate it from the metal chassis without force which I did not want to do.  All screws etc. were removed so is there a knack to seperate them?  Once seperated I can decide whether to see what is wrong with the one contact and fix it or possibly make some replacement ones.  So any advice on the final step in stripping everything would be gladly received.  

 

 

For those who like to know I am talking about seperating Part 80097-0 from part 80085-7

[Castle-Man]

Ok although no replies I thought that I would update.  I managed to carefully unclip the plastic piece from the metal  chassis completing the stripdown.  Found that one of the pickups did not have any spring in it.  Sorted by soldering a piece of phosper bronze to it and then making a standard pickup.  A bit stiff but working.

 

So when I put it back together the running was still irratic.  The problem was that the new tyres are too thick and that when you  put the loco on the rails it rocks forward and backwards on the centre wheels.  So decided to remove the tyres entirely.

 

Now running well and no grinding etc. and the lack of tyres does not cause problems with points.  If you apply power too fast then it spins the wheels but that is not the correct thing to do anyway.  Has no problem pulling the railcar which is all I want it for or a few trucks so will probably leave as is.  I know I could use spray on tyres but I really have stripped it enough times already so will live with it at the moment..