It is rarely worthwhile to clean the column end frits, just trying is often going to cause the problem described -- the columns are very often packed under very high pressures, so removing the end caps will cause media to ooze out. Even if it doesn't, the reassembled column is never the same -- a (scientist with a wrench) ≠ (a column manufacturing line) -- and column function may suffer.
First, the OP should try to isolate the problem. Can the system run for a long time without a column, just running clean eluent? If not, it may need internal repair, or inline filter replacement. The same for other system components; injector, autosampler, and detector. A new column should last many thousands of injections ... if its not abused by running under conditions that are outside of its specifications. Or even just barely with specifications. But a brand new column connected to a clean system full of filtered eluent should run eluent blanks indefinitely.