Troubleshooting speedometer/odometer problems and I was going to be cleaning sensor area as it seems to be leaking a little oil so I would also be replacing o ring back there.

Sources for o ring other than Tasca/dealership?

Hopefully my speedometer/odometer troubles are then cleared up.

Other than stopping a leak I don't think an O-ring will solve the speedo problem. The sender is working if you get either odometer or speedometer.
Dan

Here was my message I posted a few days back stating the problem:

http://www.brickboard.com:80/RWD/volvo/1465441/220/240/260/280/uncommon_speedometer_problem.html

Both speedometer/odometer do not work.

After the post I made about it's problems I pulled the speedometer board, cleaned it, reflowed some solder joints and still the same problem.

The one thing that makes both speedometer/odometer function is pulling back on the high beam switch just at the point before the highbeams switch on/off it will function-if you hold it at that position.

I took a quick look yesterday at the speed sensor and there was a bit of oil leaking. I haven't yet fiddled around back there as it seemed to me to be something wacky with the cluster due to the high beam interaction . But since the oil is leaking I figured I would switch the o ring and clean the wires up back there.

That is an odd one! I must have confused your post with someone else who basically swapped the functioning odometer for a speedometer while attempting a repair. Your problem does sound electrical, I think we need Art to look at this.
Dan

Probably not.
Any GOOD Volvo dealer should be able to get them for you.
(Maybe not willing!)