~ for the lower outer A arm bushings, is it necessary to hold the spring
~ compressed while that humungo bolt which holds the trunion ( one of my
~ favourite BritCar words) to the A arm is withdrawn? Can I place a jack
~ stand under the point where the damper attaches to the lower A arm, lower
~ the weight of the car onto it and trust that will hold the whole mess
~ together?
Having just done a TR4A with a spring compressor, I'd have to say I
would feel very nervous doing so without. The coolest spring compressor
is the one Chris has, which is a giant piece of threaded rod with
two nuts on one end and a plate on the other, held in place by a
nut and washer. The plate is drilled to slip over the shock mounting
nuts; very slick. It goes inside the spring rather than clamping to
the coils, so you don't have to worry about clearance against the
suspension members.
I wouldn't feel comfortable doing the Official MGB Trick, which
involves a jack under the lower A-arm, removing the top kingpin
nut, and then *slowly* lowering the jack; the difference is that
the kingpin on the B is longer than the free spring length, so
that the spring loses all tension before the kingpin drops out.
No fear of flying springs here.
Two things I learned last week about TR4A front ends that you
need to know:
1. The upper A arm is in two pieces, and they're not symmetrical.
The longer one goes in front so that the car has the right caster.
2. The forged spindle on which the upper A arm pivots is also not
symmetrical. You want to make sure that it is installed with the
pivot points mounted inboard of the centerline of the bolt holes,
not outboard. This ensures proper camber.
Likewise, Chris made me clean out all the suspension pieces with
a Dremel and a sanding drum, to make sure rust, dirt, and crud
are out of the way. I suspect this is most critical with his
urethane bushings -- dirt will cause them to wear away and then
you'll have just as much slop as the rubber ones -- but it's
probably not a good idea for rubber bushings either.
Oh, and as a special blessing, may you not find that a DIPPO
(that's Damned Idiot Pinhead Previous Owner) has decided
to plop a bead of weld on the bolt that holds the lower A-arm
mounting bracket to the frame; if you do, a die grinder, a
big hammer, and Snap-On's patented Flank Drive wrenches will
save the day. :-)
--Scott
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