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SAR GMA/M (rebuild)

Further disassembly and cleaning

The project rested for a while. Other work was being done on my BR 52. Progress was slow anyway as time to dedicate to the hobby was thin on the ground. In March 2024 I received the intended gearboxes and motors for the GMAM and before trial fitting them, I grabbed the opportunity to do some further cleaning and disassembly.

The challenge: disassemble this lot without breaking anything.

The jar on the left contains acetone, which dissolves cyanoacrylate glue.

 

Disassembly of the frames of the front unit

In the trial I already disassembled the superstructure of the front unit. Now the chassis had to come apart.

The front unit after disassembly and initial cleaning.

Again the black paint stuck stubbornly stuck to the metal. As concluded in the preceding disassembly trial I will use paint stripper instead of mechanical ways of removing the residues.
A thick coat of stripper was applied to the motion bracket
Before long the paint started to crinkle
And after ten minutes I could simply brush it off

The remainder in the etched lettering was picked out with a tooth pick and the part was cleaned with vinegar and rinsed with clean water.

As good as new.

Rear unit

I could easily disassemble the front units frames by first soaking them in acetone. With the rear unit that proved to be more of a challenge because the very valuable Portescap motor and gearbox were solidly stuck in the frames and consequently I could not simply dunk the unit in acetone.

I diligently took the frames apart, carefully wiggling glued joints until they gave way. This was especially tricky when removing the motion rods. After removing the wheels and the axles I got to the bare frame. I could now loosen the frame spacers and pry a knife blade between the frame plates and the gearbox sides, which broke the superglue, and I could lift the motor and gearbox out.

 

This beauty performed wonderfully after a bit of cleaning and oiling. I intend to reuse it for the build of my NS 6300.

All parts laid out in a orderly fashion, now I still remember how they came apart. This photo will help me during the rebuild.

Boiler cradle

Straight out of the box.

After some hours in acetone.

And after some prying. Note that again the black paint resisted the acetone. I don't know what this stuff is, but it is very stubborn.

All parts.

After a round of paint stripper