Rob Gray :: ontheroad :: wothahellizat :: wot2 :: diaries :: issue-005


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.