I topped up the brake fluid reservoir today....cap came off normally, as if it had been nice an tight. When I reinstalled the cap, it seems to fit quite loosely...that is, you can move it slightly with your fingers, while in the closed position.

Is this normal...that the cap sits on the reservoir somewhat loosely? Or am I a moron?

 

I happen to have a GD master cylinder with reservoir and cap sitting on my desk. It's a project item.

The cap does wiggle a bit even when fully closed. Just make sure yours is tight all the way to the last stop. It has a first stop and then turns more to lock into the last stop. From the side you can see the stops.

 

Thank you for putting my mind at ease. It just didn't seem right, that the slightly loose cap could 'hold' the brake fluid, but apparently that's the way Honda designed it.