Update: July 2023 – Addition of the Oshkosh chassis drawing for readers
I’ve had the occasion to read a post or two on the RVing sites I frequent where they are asking for a drawing of the chassis. My chassis was an Oshkosh XC chassis from ’93-’94 and I got a lot of help from this drawing. I am sure that it was actually a Freightliner chassis, with mods by Oshkosh to turn it from a truck chassis to an RV chassis.
rotated
Repair to Windshield Washer – Oct. 2015
The windshield washer (ww) had stopped working 3-4 years ago and I missed it a great deal. In 2013, when I tried to find out what was wrong with it, and why it wasn’t pumping, I found a huge crack in the plastic reservoir. I took it out from under the hood, and the thing just crumbled into pieces. So I bought a universal tank from Amazon with a new pump, hose, connectors. Installed it, wired it up, and it doesn’t work. Darn. That was the day before I was to travel so I put it out of my head for a while. A couple weeks later, I look at it again, do some electrical measuring, and find that the BLACK wire is actually the hot wire. The yellow wire with red stripe must be the ground. Whaaaaa??? Which meant I had the motor wired backward initially.
Anyway, I wire it up right and it still doesn’t work. Crap. It was difficult doing any measuring alone, and I ran out of time, headed off on another journey. Figured I’d maybe burned up the pump motor by wiring it backwards the first time. Tried to figure it out 3-4 times after that to no avail. Two years and some weeks later, after missing being able to wash my windows while driving during that time, I have a guy help me with making electrical measurements and lo, we discover that the ground wire doesn’t go to ground! Damn. It’s disconnected somewhere up under the dash. Hmmm. Well, rather than pay the guy $20/hour to search for that, I just have him make up and install a jumper wire to ground. Tada!
WW now works great. The black wire on the left is the hot wire. We added the one on the right, and taped up the confusing yellow-red wire. Next time I’m under the dash, I’ll try to find the problem, find where that yellow-red wire is dangling, maybe reverse those wires so they make sense to the next owner of this rig.
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Inverter – Optional Equipment – 2011
While I was in Fairbanks, I’d occasionally visit the local thrift store. They had all sorts of neat stuff, including tools! Once bought a nice 3/8″ Li-Ion battery operated variable speed drill with two battery packs and a charger for $35.
A couple weeks later, they had a 800W Inverter made by Black & Decker. Also just $35. So I scooped it up. And a couple months later, I got around to installing it under the hood at the front of my RV. Doing so gave me the impetus to remove all the connectors from under that black plastic cover to the left of the inverter, clean them up, replace those that were badly corroded, etc. That’s a 12V source.
I also added a continous duty solenoid with an Off/On switch next to the driver’ seat. In order to make a clean installation, I sacrificed an old heavy duty extension cable I had laying around, cut the socket off and fed the cable through the bulkhead, then to a standard electrical outlet near the floor, which is attached to the center console in the driver’s cab.
It works great, I use it to power devices that don’t need more than 6 Amps. So I can’t make coffee with it but I can run a computer. And these days I use it to power my Android with the mapping app to guide me around the country while I’m driving. And to keep its battery charged.
Here’s the Off/On switch on the side panel next to the driver. It’s that small switch with the red LED above it:
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Tracking, wandering, and steering issues on the road…
If you have the listed problems, your first step should probably be to get your four corners weighed.
Once you have those numbers, there’s a couple things to do:
1) If one corner or side has more than the RV manufacturer’s recommended ‘differential’ in weight one side to the other, then you need to rearrange your things to try to balance the weight on that axle. (I believe this number is 1% of the RV’s total weight…for example, if the RV weighs 25,000 lbs, then the differential should be less than 250 lbs, don’t quote me though…check your manual). There are cases where the house manufacturer did a poor job getting this differential low in the design to begin with, and that’s when all those add on products for ‘stability’ might be needed.
2) Go to the tire manufacturer’s website and air up the tires to their specs for the weight you measured in step one. Advice I’ve seen on RV’ing forums about setting each tire to the pressure suggested for the weight at each corner is incorrect. Set the pressure to the highest weight setting across the AXLE. So all tires on that axle have the same pressure, based on the highest weight.
3) It would be best to get your weights with typical loading. So when you first buy the rig, try to weigh it with known fuel and tank amounts (typically full fuel, zero liquids). Record and keep that info with your documents. Than drive home and fill up all the compartments with the stuff you’ll need on a trip. Then reweigh. As you can imagine, the weight of this stuff is dynamic so you should weigh a couple times per year, recording the situation particulars. Don’t forget you’ll probably find a sweet spot for how much water you want to carry so you’ll want to weigh the rig with that amount in the tank.
Once you have your RV filled with your favorite stuff and weighed, test drive on a road where you can drive in the fast lane a few miles rather than just the truck lane. This avoids the slow lane ruts caused by 10’s of thousands of heavy trucks traveling that road. Rut tracking has often caused folks to think they need an alignment when actually, it’s a tire, tire pressure, or balance problem. Many shops will tell you to not bother with an alignment because they know how massive the undercarriage on these rigs is and that they seldom need alignment.
Once you get on the road with your RV filled with vacationing supplies, does it wander, wobble, become hard steering, shake the steering wheel, drift? Do the front tires wear funny? With your weight chart in hand, you’ll be better able to decide what, if anything, you should do to address the handling or tire wear issues. It could be as simple as giving up carrying a full tank of water.
Perhaps you have an alignment problem, but you should at least check these other simple things first and for that you need to get your four corner weights. Usually, you can do that on a weekend at a state weigh station. They often leave the equipment on even when they are closed. Many states will allow you to get weighed when they’re open too. Some aren’t designed for 4-corner weighing though.
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