[DeTomaso] stock halfshaft u joint

[JDeRyke at aol.com]

In a message dated 4/21/13 5:57:47 PM, justingreisberg at hotmail.com writes:

> what fails when the shafts fail?  What part actually breaks?
> 

In the ones seen at PPC, the holes in the u-joint holders were reamed out 
oversize, probably from a prior u-joint failing, which first siezes, then 
begins moving in the normally press-fit holes. Being mild steel, it doesn't 
take long for the hardened steel cap to ream out the softer holder. Once that 
happens, the holder is junk.... and there are no individual replacement 
parts. A few had hairline cracks and may be weldable, but would need precision 
machining afterward to reestablish the normal press-fit.

In a few halfshafts used in cars with very high powered engines or that 
engaged in drag racing, the splines inside the halves actually twist, binding 
up the normally smooth sliding action. Again, the damage is irreparable and 
in most cases the halves have selectively worn together so replacing half the 
halfshaft assembly does not work. 

If a u-joint fails at speed, one end of the halfshaft breaks free & the 
splined halves extend. The 10-lb assembly spins wildly around striking whatever 
it can reach. If the inner u-joint fails (driven by the wheel),  the shaft 
will beat up the aluminum ZF case. Besides breaking the ZF cases (which can 
usually be TIG-welded if completely disassembled, the halfshaft usually 
bends. If the outer u-joint fails, one cannot get the clutch in quickly enough 
to keep the free end from vastly enlarging the hole thru the inner fender and 
ripping up rear brake lines and associated suspension parts. FWIW- J DeRyke