<VV> LM Front brakes pull

[Gary & Susan Lowell]

Help!
Last year my Stock - nothing fancy brake systemed 65 Corsa  
Convertible pulled right on sudden braking. Wouldn't pull as much if  
I applied brakes slowly. Wouldn't pull at all (hard or soft braking)  
some of the time.
Had front cylinders rebuilt, & a brake job on the front. That seemed  
to greatly lessen but not eliminate the problem. On more rare  
occasions, I would get a slight pull to the right.
Over the winter I replaced both flex brake lines and that improved  
the problem (no pulling) for a while but  now I get a very severe and  
intermittent pull to the LEFT on hard braking.
Today I bled the brakes, replacing the DOT 3 with DOT 5 with no  
change in the severe pull left situation.
The car shows about 50,000 miles mostly spent in the south with  
virtually no rust showing underneath.
I hesitate to just continue throwing parts at it without some sort of  
plan, so, I am looking for any suggestions you guys may have.
Thanks
Gary