1980 Volvo 240 Radiator, connectors and fluid capacity

I want to remove/replace the radiator of my 1980 Volvo DL. I found that it is relatively easy to take out the radiator, except for the two thin metal lines connecting to it (see images

formatting link

My questions are:

1) I have trouble loosening the connections of the two metal (aluminum?) lines going to the radiator, the ones above and below the thick rubber hose. Is it just a matter of applying brute force or more WD40? (I don't want to break off or damage the lines, though). What is the function of those metal lines, anyway?

2) What is the colling fluid (antifreeze) capacity of the radiator? And does that include the air conditioner fluid (the air conditioner sits in front of the radiator). I don't want to drain the radiator before I buy enough fluid to refill it.

Thanks for any information.

Wolfgang, Santa Barbara, CA

P.S.: I've the Haynes "Volvo 240 Series Owners Workshop Manual 1984 edition", and I find in nearly useless. Any recommendations for what better manual I could buy (Or links on the net)?

These lines are the cooling circuit for the gearbox. Inside the radiator is a copper vessel that these two pipes connect to, and the transmission fluid runs through. This is in turn immersed in the water of the radiator, so it all tends to run at the same temperature.

The connectors are collar nuts, so the pipe doesn't turn when the nut is turned. Grip the brass part (that is attached to the radiator) with a close fitting spanner, or if it is very tight, vice grips, and then use another spanner to apply force to the collar nut to undo it. You may lose a little oil from the lower one; make sure you replace it with new into the gearbox dipstick hole.

IIRC the capacity is about 2 gallons (UK measure - 20 fl oz = 1 pint); the mix of antifreeze with water will vary depending upon your local climate - it should tell you on the can. The AC is a separate system.