Looks like you have the Midland-Ross type w/ a V-band clamp, which is real easy to take apart. If you could get a new internal rubber diaphragm from Booster Dewey or such, postage shouldn't be too bad. There is also a smaller inlet valve that can go bad. I have seen on ebay. I expect that eventually somebody will start producing the internal parts to rebuild these. But must be cheap since you can buy a new booster/MC/brackets on ebay for $138.