quote:Originally posted by desert_detomaso:quote:Why has there been this shift towards these more positive types of seals ?
Because the stock style umbrella seals are made of rubber that dries out over the years, becomes brittle, falls apart and distributes little pieces of hard, dried rubber into the oil system, where they often manage to get past the oil pickup screen, which leads to jamming the oil pump rotor, which leads to a sheared oil pump drive shaft, which leads to a non-functioning distributor which leads to a dead Pantera sitting in the road.
But it is certainly your choice.
Yes this is true, but that is a function of the material used, not the way the seals work.
Umbrella seals made from a modern polymer material should not suffer the same fate as the old rubber ones that went hard and broke up as you described.
It is possible to make teflon umbrella seals.
I'm looking for the reason behind the shift in sealing style rather than seal material.