The early ones had a plastic/rubber bag, like a hot water bottle, that hung from hooks on the passenger side inner fender. If I remember correctly, the pump was mounted on the firewall. Later models had the squarish bottle like you see in the 140s, with the pump mounted on it. Those can often be found in junkyards, and if you live where it doesn't freeze, chances are pretty good they are still functional. The people that specialize in used Volvo parts usually have them too. Check in the back of "Rolling". If you can find the bottle and its basket, and the pump doesn't work, there are aftermarket, generic pumps available that can easily be adapted. Other possibilities have already been mentioned in this thread.
Bob S.