My kid has a new 90cc Kolpin quad. The other day I noticed that when I squeezed the brake lever, a bubble of (I guess) brake fluid about the size of a marble came out at the seam between the brake fluid reservoir and the cap. Releasing the lever sucked it back in. Obviously, it's not a good seal. Is this something I should worry about? The system doesn't seem to be losing fluid, but it seems like dirt and water could get in. I haven't seen the bubble again, but I have to assume the leak is still there. For all I know, most ATVs have leaky caps but people just don't notice.

 

Welcome to the forum MarkL, It doesnt sound good to me. Have you tried tightening the screws on top of it?