[DeTomaso] halfshaft bolts

[B. Seib]

Thanks for trying to help Jack
Actually 11 mm is smaller than 7/16"
Barry
  -----Original Message-----
  From: JDeRyke at aol.com [mailto:JDeRyke at aol.com]
  Sent: Wednesday, December 28, 2011 1:44 AM
  To: oldwheel at shaw.ca; detomaso at realbig.com
  Subject: Re: [DeTomaso] halfshaft bolts


  Barry, check the heads of the bolts you have with large shanks- they may
be metric marked 'BGM'. I went thru this some years ago (reported in the Feb
'04 POCA Newsletter) and what I thought happened at the time was, all
Mangustas and many early Panteras got 11x 1.5mm, 33mm long METRIC bolts with
matching elastic stop-nuts. No grade was specified. When Ford took control
and the Pantera went into full production in mid- '71, they apparently
changed to the almost identical 7/16-20 SAE bolt with elastic stop-nuts-
also with no grade specified. And the threads are so similar that BOTH the
11mm and the 7/16-20 SAE will untighten using  a 5/8" SAE end wrench, and
will both screw together using the other type's unmarked nut- sometimes,
with your fingers. So there's very likely some mixing and matching going on
out there....
  One thing I did NOT do at the time was check the unthreaded shank
diameters. I assume the production Panteras all got stub axles & halfshafts
drilled for possibly smaller-shank SAE bolts. If you have a friend locally
with a Mangusta that's unmolested, try measuring one of his halfshaft bolt
shanks. If they are the 'big' shank bolts, you can TRY ordering 11mm
Mangusta halfshaft bolts from Wilkinson or others, but I suspect that
short-unthreaded-shank 11mm bolts are going to be very difficult to locate.
  Remember also, you do NOT need gr-8 (or the comparable gr-10.9 metric):
those are very strong in tensile but not so much in shear- which not exactly
whats needed in this application. Gr-5 (or the comparable gr 8.8 metric) are
much tougher in shear and work better as halfshaft bolts.
  At the time I thought I'd settled the metric vs SAE halfshaft bolt thing,
but apparently even after 32 years I can still learn something about these
beasts- J Deryke