Cause of grabbing brakes

[Dave Mann]

I have a friend with a 1931 boat tailed tourer which he has used as everyday transport since the 1950s. He relined the brakes in the summer and soon after when he brakes the brakes grab there is no gentle braking. So he relined the brakes again with linings from another of our cherished suppliers, these have now developed the same problem and with winter approaching and possible icy roads he needs to find an answer. His car has coupled brakes and 1.25" brake shoes and drums. I've gone through the usual loose brake shoe pivots, broken brake shoe springs, oval drums, worn king pin bushes and or shackles. Help, have any of you got any ideas as to the cause.