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AVM Freewheeling Hubs Inside
Just a quick photo of the inside of the freewheeling hub mechanism. I couldn’t find anything on the net about these hubs, so maybe this will help someone. See post 21 also.
It’s pretty obvious how they come apart once you get into them. There’s a circlip that holds the centre piece inside the outer ring (hidden in the photos). Get this off and the whole thing falls apart.
How the hubs work, is that the centre selector piece is turned from the outside, but the mechanism with the springs and gear is prevented from turning by a pin, and therefore slides up or down the thread, disengaging or engaging four wheel drive. The outer castle shape of the gear is always engaged with the wheel. When the mechanism slides out (towards the centre of the vehicle) the centre of the gear engages with the spline on the end of the half shaft, thus locking the half shaft and wheel together.
The easy way to get these apart is to pull out the small pin and just unwind the gear piece. I was reluctant to do this, not knowing how the pin was held in place, and how well it would go back in if removed. I managed to get the mechanism apart without removing the pin, by loosening the circlip and jiggling everything apart. There was no way I could get them back together this way though. In the end I just pulled the pin out with pliers. It’s actually a folded piece of metal, and if you slightly spread the fold out, the pin will be nice and firm when tapped back in. I tapped them in with thread lock.
Two tips. 1. Just pull the little pin out and everything is easy. 2. You will need circlip pliers. I broke one circlip using snap ring pliers, which are almost the right tool. There’s no chance you’ll pry the circlip off undamaged with a screwdriver.