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MB GPW G503 WWII Military Army Jeep Flywheel Ring gear replacement

This article shows the steps to replace your worn out flywheel ring gear on your WWII G503 Military Jeep (Willys MB or Ford GPW)

This article applies to both Willys MB and Ford GPW WWII Military Jeeps 

1. While into disecting your project, many times you come across a weak starting issue. In many cases, it is due to a flywheel ring gear being worn out. Here you see a perfect example where the flywheel ring gear are nearly completely worn out.

2. Replacing the ring gear is not a difficult task. Here we show the new 97 tooth ring gear with the new replacement.

You will need:

- a torch to heat the ring gear off and heat the new one on
-4x4 block of wood

3. Place the flywheel on the 4x4 block of wood. Heat the ring gear for about 2 passes all the way around the ring with the machined side up. This will expand the ring from the flywheel.

4. Turn the torch off, and quickly tap the ring from the flywheel. This should only take a couple of taps around the ring and the old ring gear should fall off.

5. Turn the flywheel over with the machined side down, then place the new ring gear on the flywheel (still on the 4x4 block), the ring gear should be a little short of fitting on the flywheel. Now heat the the ring gear up with a torch (as you did before taking it off). The ring gear will expand enough after you take about 2 passes around the gear.

6. Turn the tourch off and grab your punch and hammer and tap the ring gear evenly around the flywheel.

Tip: You want to avoid having the new ring gear cool off..having to re-heat it as it could cause warping.

7. After tapping the new ring gear on the flywheel it should cool off and tighten up around the flywheel.... Looks good!

8. Wow, what a difference when you compare the old worn ring gear to a new one! Looks great, and now the starter will hit the gear terrific.

9. Here you see the flywheel installed on the crank and looks great, ready for the clutch plate to be installed.

Special thanks to Mike H. who provided the pictures and details for this article.

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