[TR] Rear Hub Bearing Replacement

[Michael Porter]

On 1/17/2018 11:11 AM, Jack Mc wrote:
> Some people (including me) believe they were all broken the day they cut the key way in the shaft - it just takes 40 to 50 years for them to finish breaking. 2 of the above 3 owners were extremely lucky in that they broke at low speed while accelerating, felt something wrong and brought the car to a safe stop before the wheel/hub assembly left the car.  In the 3rd case ...well ...that happened during a race - the wheel/hub/brake assembly left the car, the flailing half shaft beat the trailing arm into many pieces, but the car hit a tire wall before it could finish turning over. You might not be so lucky, so please skip option 1 and go straight to option 2 or 3.

Maybe worth mentioning here that companies doing marine shafting deal 
with these sorts of problems all the time, mostly because they are 
working with much longer shafts, where torsional stresses are quite a 
bit higher and there's lots of wrapping and unwrapping of the shafting, 
which greatly increases the flexing in the shaft and fatigue in the 
driven end.  Attention to the keyways (eliminating sharp edges, thus 
reducing stress risers), radiusing the corners of the keyways and 
chamfering the key edges to fit, and then lapping the shaft and hub 
together so that the bulk of the torque is taken up in the mating 
surface area and not the key and keyway make the shaft last much, much 
longer.  These are not the sort of things that are done on a production 
basis, but can be done by some diligent and patient handwork along with 
a little machining.

All that said, the money spent to upgrade to CV joints is probably worth 
the investment.  If splined shafts and u-joints were superior, the 
industry would never have moved to CVs in the first place.

If one simply cannot afford the additional expense, massaging the 
existing hubs and stub axles (after they pass crack detection tests) as 
above can help.  There's little that can be done with the axle splines 
except for making sure they're free of burrs and cracks and 
irregularities, that they don't show abnormal wear, and that the boots 
are good and that there's plenty of a suitable lubricant (on that issue, 
today, I'd opt for a fully synthetic wheel bearing grease, which doesn't 
dry out and clot up like older greases).


Cheers.

-- 


Michael Porter
Roswell, NM


Never let anyone drive you crazy when you know it's within walking distance....