Ailing Robinair pump

[Gary Beasley]

My pump is not pulling as much vacuum as it was when I got it. I changed the oil a while back with the recommended brand and type. Its a Robinair 15101-B. Is there a repair I can do that will bring it back to par? I haven't been able to find any repair kits for it.
If this is a warning that the pump is on the way out whats a good replacement that's durable, performs as good, and won't break the bank?

 

[mredburn]

Has it shown any signs of leakage like loss of oil or damp spots around the housing. Its possible that a gasket or seal may be leaking. Have you removed the front housing at all?

 

[Gary Beasley]

I haven't removed the front housing, is there a gasket to worry about on it? It's pretty noisy until the vacuum loads it down some, seems to me the coupling is worn. There doesn't seem to be any leaks