#I too have experienced problem brakes on a series 2a.
I don't like to dwell on it but I can remember the sense of despair at my efforts to establish efficient brakes, my wife ended up with the legs of a champion cyclist, no matter what we did, vacuum etc. was all to no avail.#
For me at least, a remote servo was the answer, you take the pipe from the MC in one end and the pipe to the brakes in the other, and a vacuum pipe to the manifold. There is a bleed nipple fitted and that's it, talk about a sense of relief.....!
The gear I'm talking about is termed a " Remote Brake Booster/Servo" and are made by PBR.
My unit has the details:-#
PATEN BRAKE REPLACEMENTS, VH40-1, Model 2.
The main problem is finding somewhere to mount it, I ended up making a bracket, mounted off the chassis on the manifold side of the engine bay.#
I don't know if that model is still current but they have one listed on EBay, with the designation VH-44 At varying prices, the cheapest being $175 post paid which I would think, do the job.
If you email PBR and quote the above details, I feel sure they could offer you the correct alternative.
I did the job myself without an probs.
Anyway guys, hope all this helps, talk soon,
Norm.