I've been involved in an off list discussion with David Wingett about his
Corvair rear axle replacement for the Triumph IRS rear axles. I'm interested
because I have first hand experiance with a rear axle failure - it is not a
feat that I want to repeat. The following is a summary of the conversion.
The standard qualifications apply wrt financial or personal interests.
I plan to purchse a set simply because it is much cheaper than a trip to the
hospital.
Hope this helps
Lee Janssen
First the cost: $1200.00 with your new or magnifluxed splined yoke
per par. They will NEVER fail!! The set I have on my race car I
bought 5 years ago. They were Custom made and cost an arm and a
leg. These are bolt on ready to race.
Modifications:
You must grind the trailing arm and break back plate, in 4 spots
for clearance for the larger u-joint yoke. I will supply a
template or drawing.
Details:
The billet cut 6061T Aluminum carrier hubs for a Corvair
axle/flange mount to the trailing arm the same as the stock
assembly. I weld up one of the 5 lug holes on the Corvair axle /
flange then re-drill 4 new holes at 4 1/2" on center (the early
Corvair axles had a 4 bolt pattern. I use the stronger later
model that has a 5 bolt pattern). The axle is magnifluxed then
turned on a lath to insure that the mounting face is flat. All the
bearing surfaces are polished. This makes disassembly for
inspection easier. All the parts are magnifluxed , painted then
assembled. The Corvair axle has a very large u-joint yoke that is
splined to fit on the axle. This yoke is machined to a smaller
size, to more closely match the hole in the trailing arm. This is
still too large and some grinding is necessary to allow it to pass
through the hole.
Replacement Parts availability:
The u-joint is a NAPA #319. I believe that it is a Chevy to Ford
conversion piece. With one set of bearing caps being smaller then
the other. The stock Triumph yoke (TRF# 142437) is then machined
to fit this smaller end. All the bearings and seals are readily
available at NAPA.
Studs:
I have installed 3" . 7/16x20 studs. If you would prefer I can
press in a stock set, or even 1/2x20 studs .
Disk Brakes
I assume your using drum breaks? I have made these to accept a
disk break mounting flange and hope to have a Wilwood conversion
set up by mid summer.
Problems associated with used axle yokes:
The yoke problems are: The obvious like an egg shaped hole or a
dent in the hole both from a past failure. The magniflux test
will pick up fractures in the u-joint area and the splined tail.
The hard one won't show up until we set it into the fixture to
machine it. We have found that the holes for the u-joint are not
always concentric to the center line of the shaft. We enlarge
this hole by a few thousandths so we have a very small amount to
fudge. But if we can't bring this into specs. I wont use it. This
is why I request a known good part and ask for extras.
David Wingett
9600 Reese Rd.
Clarkston, Mi. 48348
(248)625-9478
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