Convertible Top Motor

Anyone know if I can purchase an o-ring for the reservoir? I replaced both of the lift cylinders and when I went to remove the fill plug, it broke. Half of it fell inside the reservoir so I split it open to remove it.

I purchased a new plug, lubed the o-ring and reassembled. Well all of the fluid is gone, so I need a new o-ring.

Can anyone help?

Thanks in advance!