O-ring for convertible top motor

[nialithe]

Had a rusted roof motor, replaced just the motor. Did the relocation, but now I have a problem. The o-ring is blown out and the replacement I got with the motor isn't making a positive seal either. The top is functional, but only until the fluid leaks out again. BMW doesn't sell just the o-ring, but the whole motor and pump assembly. Has anyone else had this problem and found a solution?

Edit:
Found that it's the pressed in seal between the collar and motor. Seems like a very specific part. Anyone know where to buy this seal or the whole collar with new seals in it?

[nialithe]

Here are pictures