My '62 Mk2 has developed a vacuum leak somewhere, leading to brake pedal push-back when stopped in gear after about 10 seconds. One opinion is that there is an internal leak in the brake booster (not the original. It’s the updated type.) Another is that the problem may be the vacuum line from the intake manifold. Vacuum tank seems OK. Does anyone have any other ideas I could pursue?
Do you have a Mity-Vac hand vacuum generator?
If not buy one!
You can bleed brakes and other hydraulics by yourself.
Yes, many of them have a gauge and maybe you could rig up a temporary T fitting and connect the Mity Vac and see what your vacuum readings actually are.
Check the one way valve on the vacuum tank, if inoperative a reserve cannot be obtained.
Are the pipes at the one way valve connected correctly?