However, it should operate w/o "help". The top canisters are the first thing I would check for correct performance. The interior sides should be smooth. If pitted, you should remove the pits. Then, a light honing similar to what you'd do with an engine cylinder should be done.
The leather seals should be pliable. If not and they are in otherwise good shape, I'd suggest you soak them in Neatsfoot oil. If the leathers are "shot", you'll need to replace them. There is a seal within the top plate that surrounds the piston rod. That seal must be doing its job. If not, replace it.
The piston rod must be smooth and free of pitting. If not, it too must be replaced.
There is a small gasket that seals the top of the canister assembly to the canister. That is almost always rotted away. A bit of silicone sealant works well in lieu of the gasket.
Moving on: ALL the lines, both rubber and steel must be leak free. Check all the connections. If you have a vacuum pump, plug one end of each line and apply vacuum to the opposite end. The vacuum should hold steady. If not, figure out where the leak(s) is and repair as necessary.
That's really about it. Not a difficult task but a bit time consuming to do properly.
On my restorations, I have always hidden a vacuum tank beneath the rear seat cushion. I install a check valve within the line. This "trick" has proven to provide a little extra "umph" when the top is in a near 90° open position.
Finally, make certain all pivot points of the top assembly are not worn. If they are worn (elongated) it will require perhaps more vacuum to overcome that mechanical disadvantage than the car can provide.
Hope this helps...
Mike Kubarth