dodge guy wrote:
Speaking of miles. I’m looking at some DP’s 02-07 with 89-130k miles. I know what to expect from the F53 (V-10) chassis. But why should I look for as fat as the chassis goes for diesels. I would like to have a Cummins as that is what I know. Anything as far as the air brakes and air bags to look for? What is the life expectancy of the air bags. Any type of wear or maintainance I should look out for!
dodge guy,
Looking at used diesel motorhomes is just like looking at any other used car/truck/boat etc. They're just bigger. Some are treated nicely and look the part. And some represent the old cliche, "rode hard and put away wet". Although you've state you'd like to maybe end up with a Cummins powered unit, don't discount the CAT equipped ones. If you do, you'll maybe loosing out on some great floor plans and also maybe some great deals.
Yes, CAT pulled out of the over-the-road engine making a few years ago but, there's still a zillion CAT service centers all over the place. CAT parts are still abundant. There are thousands and thousands of CAT powered motorhomes, over the road trucks, cement trucks, fire trucks, delivery trucks and more still out running around every day. This is your choice.
As for what to look for on a chassis, well, like any used vehicle, check for rust, possible damage, broken body to chassis supports (seen that on a few), and a good going over. Diesel coaches for the most part, are air brake equipped. And with that comes air systems. DOT and other regulatory agencies have set up parameters for air systems to operate in.
That is, normal air pressure for most given air controlled systems will be right close to 120-130 psi, tops. An air system, if in good shape, will start off at 0 psi and, at high idle, (around 1000 rpm) should hit the cut out at about 1.5 to 2 minutes, plus or minus a bit. Your "Low air warning buzzer" should die off at very close to 60 psi and above. Your emergency brakes are normally scheduled to auto-apply at or near 30-45 psi, give or take.
There will be an air compressor, a governor, an air dryer, various air lines and valves and of course, air tanks. I could go on but, you can learn all you need about it on line and from other folks on here. As for air bags, well, in most air "sprung" coaches, you'll have four air bags, one at each corner. Some have more. The regulators for the air bags are what's called "ride height sensors". Those control just how much air is placed into the air bags so the coach has a specific ride height.
They also handle the loading of the coach. The more you load into the coach, the heavier it is. And the more it will want to lower itself due to the more weight. BUt, the ride height sensors will see that and, act accordingly and apply more air to the bags, to bring it back to standard height. And, consequently, if you lighten the coach load, they will see that too and let out what's needed to keep the coach at its intended ride height.
How long do they last? That's a $64,000 question. Ours are 15 years old and still working flawlessly and the coach has 88,000 miles on it.
Now, here's a semi-controversial topic. Rear vs side radiator. I could type for pages on this but suffice to say, a side radiator is a bit better for those that do their own maintenance due to the fact that the rear of the coach is a bit more open for access to the engine. Whereas, rear radiator coaches do provide for hindered access for obvious reasons. There are quite a few of us on here that have rear radiator coaches and we do our own work. It's not all that bad. I've had my radiator and CAC (Charge Air Cooler, aka Turbo air cooler) out a couple of times and done maintenance. No biggie. You'll get lots of opinions on this.
The brakes on diesel coaches for the most part are air controlled. And, they're a lot bigger than any gas rig. They normally last a whole lot longer than their counterpart gas rig brakes. One of th reasons is because many, many diesel coaches are equipped with one or the other of two auxiliary braking devices. The first is what's called a "Jake" brake. The true real name is a "compression" brake. Jake is from the name Jacobs who, purchased the rights to it decades ago. That kind of auxiliary braking system is normally on larger coaches with larger diesel engines. And, it quite often has various stages of operation and or selection. Depending on the selection panel in the coach, it can be weak, middle of the road or, I'M STOPPING YOU RIGHT NOW!
The second type of auxiliary braking system is what's called an Exhaust Brake. Those are merely a valve installed in the exhaust tubing close to the engine. Close the valve, and no exhaust is allowed to leave and, guess what, that backs up the engines ability to breath and, you begin to slow down because of it. Those are either ON or OFF. There's no level of selection on those.
There's others too like variable vane turbos that are a form of brakes too but, I'm not very familiar with those.
But, in short, with the proper use of those auxiliary braking system, your service brakes will live a long happy life. Our brake are currently about 5/8" to 3/4" of an inch thick, at 88,000 miles. I seriously expect them to go easily to 150,000 miles.
Anyway, there's lots more to offer here but, that's a start. If you find a coach, give it a good inspection, top to bottom, front to back, side to side. Hopefully you'll get some good maintenance records to help with your decision but, if not, it's not the end of the world. We didn't and our coach is just fine. Good luck and happy hunting. There's lots of them out there.
Scott
