[DeTomaso] halfshaft bolts

JDeRyke at aol.com JDeRyke at aol.com
Wed Dec 28 02:43:40 EST 2011


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


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