| Wed
20 Jun 2007
I've spent all day working on...well you tell me.
Below is a photo depicting part of today's project.
What do you think it is?

Apart
from working on whatever it is, I've been freezing
my aaah, you-know-what off. According to the weather
report it's been the coldest June day in Queensland
for some time, actually the weatherman said EVER,
which means since records were started in 1770 or
whenever. It was -9 in Towoomba last night and in
the teens in nearby Brisbane today which, when combined
with the high winds, brought the temperature down
to about 2 in the middle of the day.
Now
I guess I won't get much sympathy from my northern-hemisphere
readers given the winters you have up there, but by
our standards 2 degree is about 30-35 degrees under
the money.
Thu
21 Jun
That's right, I bet you got it straight away. It's
a spare wheel lifting thingy which for reasons of
conciseness I'll call a cradle.

The loading procedure.
I've
added a winch to do the lifting and a small ledge
to sit the wheel on when it's at the correct height.
The winch is a worm drive version of the common boat
trailer winch, I chose a worm drive because it gives
more precise control than the usual cog/ratchet style,
and also it can go up or down without changing the
handle position or flipping latches or whatever.
The
ledge makes it easy to rotate the wheel to align the
bolt holes. Rotating the wheel with the tyre on cradle
is very difficult due to the friction, so I push the
wheel unto the ledge and lower the cradle a bit which
leaves the steel rim sitting on the steel ledge. There's
very little friction, so the wheel is easy to rotate.

The worm-drive winch.

The ledge used to rest the wheel on
for rotating to align the holes.
There's
also a small loop made of 8mm round bar welded to
the outside edge of the cradle. If I lay a tyre lever
on the ground with it's hooked end inserted into this
loop, then roll the wheel onto the lever and lift
the other end, the wheel slides into the cradle.
It's
easy to roll a wheel to a position next to the cradle,
but this rather neatly solved the problem of getting
a 150kg wheel to move sideways into
the cradle.

A tyre lever inserted into the loop.
All
in all the system seems to work well and it's pretty
low-tech, which is one of the things I am aiming for
with this motorhome. Low-tech means low-dollars and
low-maintenance.
Fri
22 Jun
It's shopping day so I lose a few hours going into
town. On my return I start removing all the brackets
on the chassis that are for the shock absorbers, winch
cable re-routing rollers, and bump stops.
I
will be making new shockie mounts for several reasons.
- The
position of the old mounts causes me to have three
heavy rollers mounted on the left hand side of
the chassis to route the winch cable around the
shock absorbers. By redesigning the shockie mounts
I can dispense with all these rollers.
- In
the case of the shockies on the rear axle the
shockie mount will be integrated into the body
mount.
- I've
realised that the shockies do not have enough
stroke to match the axle travel so in theory,
when crossing a ditch or something, we could find
the entire weight supposedly being handled by
the bump stops actually being born by the shockies.
This
takes the rest of the day, and in fact I don't finish
because the pins securing the lower half of two of
the shockies refuse to budge.
Sat
23 Jun
The shockies have a pin (actually just a large bolt)
connecting them to the axle. This pin goes through
a tab welded to the axle, then through a steel sleeve
(which protects the rubber bush) and back out through
another tab.
It
appears that the sleeve has fused to the pin, probably
with rust. Normally you would just bash it out, or
if that didn't work heat it with the oxy then bash
it out. But in this case I can't hit it directly with
the hammer because there's a brake cylinder in the
way, and I don't want to heat it because I'll ruin
the rubber.
NOTE:
Never directly hit the end of a bolt, always screw
a nut on the end to protect the thread.
I
come up with the following idea.

The recalcitrant pin and the method
of extending it.
I
screwed a nut onto the offending bolt but still could
not get access with the hammer, so I then screwed
another bolt onto the nut. This effectively extended
the bolt I am trying to move and gives me clear access
to whack it with a hammer.
In
fact I find that in this case using only one nut did
not give enough thread to each bolt and the whole
lot would come apart after a couple of belts, so I
weld two nuts together to form a larger coupling.
After
some time laying into this lot with a large sledge
hammer while trying not to hit the brake cylinder
I almost give up and am considering using the oxy
anyway and sacrificing the rubber. I decide to have
another go and this time think I detect the slightest
of movements. Another couple of belts and and it's
clear that the pin has moved just a smidgeon.
Soon
after the shockie is free. A five-minute job has taken
an hour or so.
Once
the shockie is out of the way I can start on a new
mount.

The main member of the new shockie
mount before bending. Note the uneven pattern for
the mounting holes, I'm using whatever holes are already
in place on the chassis.

And after bending.
It's
getting late and I really need to consult my design
before going any further so I call it a day.
Sun
24 Jun
Having decided that I'm doing the right thing with
the shockie mount I have to do another three, and
as it's much easier to work on this without wheels
in the way I remove them.
I
also have to remove the handbrake mechanism as it
shares some bolts with one of the mounts and is also
in the way.
This
gives me pretty clear access to all of the rear chassis,
and with all the old mounts and rollers gone I can
get a much better idea of what needs to be done.

The stripped rear part of the chassis.
The
poor truck will be in this state for some time, before
I put it back together I have four shockie mounts
and three body mounts to make, I also have to clean
up the old handbrake mount and linkages.
I've
done all the drilling and bending of the main members
for the shockie mounts and now have to trim them to
a better shape and add gussets.
Mon
25 Jun
I've finished two of the top shockie mounts, well
at least they look finished because I've done all
the time-consuming bits like what I call the "cosmetic
welding". Cosmetic welding is really just done
to fill in the gaps where two plates meet and, as
the name suggests, I do it to make the assembly look
professional.

A nearly-finished top shockie mount.
I'll
do some internal fillet welds next time I fire up
the big welder, these will be structural.
Have
I mentioned the bad weather? Using old-style measurements
we've been having two- or three-dog nights of late.
Luckily for me one of the resident dogs here (there's
now three, two big ugly Mastiff crosses and a normal-sized
Healer) has taken a shine to me.
Rex
will come into my "lounge room" at night
and lie on my feet which keeps them from freezing.
He's also taken to climbing up onto my lap, and while
he's a bit large for a lapdog, he certainly keeps
me warm.
He
even likes to help me with my tyyyyyyyyyyping, but
has a way to go with that particular skill set.
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