re:
"I also use a flat washer, as well as a lock washer, ..."
I gave this subject (fastening) a lot of thought and a bit of research and
decided to clamp my shocks with hardened flatwashers and threadlocked
bolts properly torqued. I have not had one come even close to loose on
perhaps 40K miles (re-tourqed every 20K miles or so due to other work on
the suspension).
>From Carroll Smith's definitive book "Nuts, Bolts and Fasteners Handbook"
(originally entitled "Screw to Win," I have heard):
"Neither the spring washer nor the wave washer do anything worth talking
about--other than to provide the user with a false sense of security."
--and--
"Once compressed, the spring washer is nothing but a flat washer. If,
for whatever reason, a bolt should loosen to the point where the spring
washer opens enough to become a spring, there was too little residual
stress in the assembled bolt for any sort of safety."
Anybody use lock washers under head bolts/nuts?
Smith does recommend star washers, in limited, small applications.
If you wanted to use the "belt and braces" approach you could drill the
heads of the bolts and properly safety wire two to each other. However, I
believe once these bolts have begun to work loose it's only a (relatively
short) amount of time before you have serious trouble ... the safety wire
only buys you a bit of time, perhaps for a warning.
I recommend the (late) Mr. Smith's book to anybody doing their own
work. The non-glamorous business of properly fastening things together
is quite possibly the most important and fundamental mechanical skill (I
know in aviation it's a religion).
Of course, everybody on the List has a set of quality torque wrenches--
preferably calibrated--right?
bs
********************************************
Bob Spidell San Jose, CA bspidell@comcast.net
'67 Austin-Healey 3000 '56 Austin-Healey 100M
********************************************
Subject: Re: Shock Curiosity
> Mark:
>
> I believe that the 'gold' colour on the shock bodies indicates that the
> shock is a 'factory' rebuild - from the days when the factory was still
> doing this. Same as the red colour on the gearboxes, which indicated a BMC
> rebuild. I know for sure that this was done in Canada, and I would think
> that it was likely system wide.
>
> The front shock bolts should be 1 inch (I just measured) - that is long
> enough to engage all of the threads in the mounting plate captive nuts, and
> won't foul the spring plate below. Alan's observations are good - I
> re-install using grade 8 shouldered bolts. I also use a flat washer, as
> well as a lock washer, and a bit of blue locktite on the threads. Success
> depends on the flat washer spreading the load on the shock flange - damage
> on the shock body will not allow a reliable grip, and the shock will loosen
> over time, not what we want!
>
> No question about it being a bit of a weak point in the design.
>
> Earl Kagna
> Victoria, B.C.
> BT7 tri-carb
> BJ8
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