Triumph Repair: vacuum, weber carbs, vacuum problem

Question
Howard,
I installed a set of weber carbs on my 73 tr6, all went well and it has tons of power. after several weeks i'm having a brake vacuum problem when i drive it.I lose all vacuum assist,if i down shift the vacuum assist works otherwise i have none.I can find no leaks and setting at idle in the drive way the brake pedal is solid. any idea's.

Answer
Hi Bob,

You didn't say if the Weber conversion came with it's own manifold or are they adapted to the standard manifold? Is there a vacuum reservoir on the car? (Several ball shaped cans made of plastic and made into one unit) Are these down draft Weber carbs or side draft Carbs?

If the Weber conversion came with it's own manifold, where does it provide vacuum at and is it the same size port as the old one?

If the car runs good then the engine is producing vacuum (except at full throttle where it produces the least vacuum but no less then 5 in hg)

Howard