The 'four leaves' are now supposed to be OK, but early ones were weak. I don't know when they changed. I do know where mine is banging. Where the spring passes under the rear wooden bulkhead from the front shackle, as it emerges into the rear axle space, there's about two inches clearance, maybe a bit less, when the car is jacked up. But when the weight is on the wheels this is much less of gap, and both sides show witness marks where the spring is hitting the wood, both on the wood, and on the spring.
At least I've found the source of the banging. It doesn't do this very much but it's like having a man with a hammer under my seat.
