Which hinge is this? Is it the front shin flaps containing the grey shin vents?
I transformed MP10 for the first time yesterday and it took me quite a while cuz I didn't want to scratch the paint. The hinges of the leg flaps on my MP10 were also quite tight and I had to really nurse the flaps apart gently. But once I got the flaps to flip, they began to loosen up nicely and move much easier.