At 07:02 AM 10/15/98 -0500, Ronald Olds wrote:
>I'm to the point of installing the front suspension back on the frame and
would like to know how tight to torque the bolts for the top and bottom
links and the nuts for the A-arm pivots.
Well for starters, the bolts for the top and bottom swivel links are fairly
high strength 1/2" bolts with fine threads and 3/4" hex nuts and
lockwashers. If you use a 1/2" drive socket with a ratchet handle about
10" long you can just about pull your arms off without torquing them too
tight, so give them a jolly good pull. They will accept well over 100
lb-ft of torque.
The nuts at the inner ends of the lower a-arms are a similar size, but they
don't have to be all that tight, so long as you use elastic stop nuts (self
locking nuts with nylon locking insert, commonly known as aircraft nuts),
or a castellated nut with a split pin to keep it from unscrewing.
The bolts in the lower a-arm assembly are 5/16" with 1/2" hex heads and hex
nuts (or a similar metric size for the TD). You can tighten these
adequately with a 3/8" drive ratchet wrench with a handle about 7" long.
With a 1/2" drive ratchet you could easily break the bolts by over tightening.
And now for a crash course in how to tighten bolts near the max without
breaking them. Get a hand full of short hex head bolts in assorted sizes,
1/4", 5/16" and 3/8", several of each with some hex nuts to match. Fine
threaded grade 5 fasteners would be the prefered models for this purpose,
since these (or similar metric or BSW sizes) are most commonly found on
MGs. Start with the smaller sizes and work your way up.
Put a bolt in a bench vice with the head down and the threaded end up, with
the head about flush with the top of the vice jaws, and tighten the vice.
Put a nut on the bolt and screw it down until it touches the head of the
bolt. If the threads of the bolt do not go all the way to the head, use a
nut one size larger for a spacer. Then select your choice of an implement
of destruction (BFW) and torque the sucker down by hand until you break the
bolt.
Repeat this process several times with different sizes of bolts and
wrenches until your arm knows by feel when the fastener starts to yield
before it breaks. Thereafter just remember to stop before you get there
and don't over tighten it. You will then have a calibrated arm that works
for torquing fasteners in all but a few critical applications (like use a
torque wrench for cylinder head and connecting rod bolts).
Barney Gaylord
1958 MGA with an attitude
PS
Try not to skin your knuckles while you're practicing.
BG
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