Diaphram style pump?Make SURE the threads for the retainer screw in the center are good and holding, and that the two plates for the diaphram are good -- if the screw works loose (there is loctite in the kit to stick it in, please use it!) or the plates are rough, the diaphram will tear quickly.
Also, check the condition of the check valves and roller/cam -- I have a long story about the vacuum pump on my brother's 75 300D.
Peter
