[Healeys] Rear Half Shafts

Fred Crowley fredcrowley at teamhealeytexas.com
Fri Nov 12 20:36:36 MST 2010


Folks,

Does anyone have some rear half shafts for a 3000 that they would be willing
to sell?

This past weekend, at the season ending race at Texas World Speedway, I broke
the right rear half shaft on my 62b Healey race car. While I had a spare,
Ibm looking for a couple more as backup. This is the second axle Ibve
broken on the car in the past 10 years. Must be that cheap British metallurgy.
They only lasted 42 to 48 years with a lot of racing on them. I am mindful of
that old axiom that once the part is replaced, and you have a spare, it will
never break again. If you donbt have a spare after replacing it, it is
almost a sure thing that it will break again, and there will be no other
Healeys around to steal one off of.

Both half shafts have broken broke right at the radius to the flange. Of
course Ibm putting a lot of stress on these axles that they were never
designed for. Number 1 is the race tires available today are much stickier
than back in the day. Secondly, they werenbt designed to be raced over a
period of 20 years. One of the advantages of the rear half shafts on a big
Healey, is that when an axle breaks, you donbt loose the wheel. The axle
flange fits over the studs on the bearing hub, and when the brake drum and
splined hub are bolted on, the bolts hold everything together. The only
problem of a broken rear half shaft is that no power is transmitted to the
associated wheel.

A relatively simple test to check the axles is the bpingb test. With the
axle out of the car and held vertically by the axle shaft towards the splined
hub, use a wrench (doesnbt have to be a whitworth!) and strike it against
the edge of the flange. If the axle gives off a high pitched resonant
bpingb (much like a tuning fork), then this is a good indication that the
axle is most likely OK. If it gives off a sound that is flat, then the axle
most likely has a stress crack b donbt use it. This test is almost as good
as magnafluxing. Since the rear axle on a big Healey is pretty straightforward
to remove, it is not a bad idea to periodically test.

I would also strongly recommend checking the front stub axles on the 3000. The
stock units are notorious for developing stress cracks right at the radius
(especially on stock units after all the years of use). If the front axle
breaks, itbs going to damage the car, and will certainly require a change of
underwear for the driver. I installed Denis Welchbs competition stub axles
on my race car many years ago (much stronger and better metal than the stock
units), and check them yearly just to be sure.

Cheers,

Fred Crowley
Team Healey Texas


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