I was asked by a few friends over the years,, what do I look for when buying a used RV,,,Motor home, trailers. (which includes bumper pulls and 5th wheels).
I first look at over-all structure. Looking for damage, especially water damage.
I walk around the outside looking at the siding , and looking underneath at the under carriage. This will include, holding tanks (if equipped).
I will check the tank drain valves for easy movement and any leakage.
I look at the wheels,tires axles and springs. I don't get discouraged if the tires are junk,,,, tires are easily replaceable.
I will grab each wheel and give it a shake back and forth,, this will give me a moderate indication if the bearings are loose. ( If the wheel has play in it,, the bearings are loose and havent been checked or serviced in awhile).
After I have done my outside walk around, I enter the RV. Looking at the door latch and hinging. Paying special attention to the flooring just inside the door.
Checking for soft flooring as I step in. I then walk from front to back feeling the flooring as I look at the ceiling for apparent water damage. I look especially close around the roof vents and a/c unit area,(if so equipped). I look at the lower framing of the windows,(water tends to puddle on lower sections of the windows if there is a water leak). I check the mechanical handles of the window cranks to see if they work. I open lower cabinets,especially the kitchen cabinet and look for previous leaks or potential problems with plumbing,, water lines, drain pipes etc.
I will step into the shower and feel the flooring under neath, feeling for soft spots, and to see if I can actually turn around as if I am taking a shower.
If the shower has a sliding hard curtain or door, I look at the tracking for previous leaking under the rails. I look around and behind the toilet for leaking connections or evidence of previous plumbing problems. ( checking for a soft floor around base of toilet.). While I am in the bathroom, I check the walls by feeling for soft spots. (most people don't realize that while showering, 99% of the people don't open the top vent to let the steam and moisture escape,, leaving the walls to absorb the steam and moisture.)
If the trailer is NOT plugged in to check appliances, you are pretty much at the mercy of the sellers word for it. At this point, visually look at each power receptacle and pop the covers off the ceiling lights and look for evidence of water damage inside the outlet. If it has an onboard battery, check the connections and what ever wire that is visable. If there is an converter under the cabinet,, look at the wiring, both the 110.V and 12 V. If there is a breaker box,, inspect the breakers for damage or burns.
If at all possible,, take a second look on a rainy day... this is the perfect time to check for water leaks.. a plus is, during this time, if you can visually check the roof from the outside, look for heavy puddling,, I call them roof lakes.
This will indicate roof sagging or a soft roof.
Before finishing up a quick check over, DON"T forget to check the hitch coupling. Check bumper pulls tongue and ball hitch assembly. Does the hitch lock securely, and safety latch engage?. Are safety chains properly attached to tongue frame?. Is the wiring plug intact?.
On 5th wheels,, is the king pin in good shape, with no flat spots on the upper portion of the pin?. Is the Butt plate on the bottom of the pin not rounded off.? If it has a pin extension, (90%) of 5th wheels do). Check the mounting hardware and bolts for stress cracks and rusted bolts. Check hitch mounting frame area for stress fractures or weakened areas. Is the wiring plug intact?. Does it have a break away switch installed and intact?
On both trailer types,, does the lifting cranks work properly,, up and down?
If an electric was installed,, does it have a manual over ride?
On Motor homes,, all the above is relavent. But with a motor home, you have an engine and transmission and rear axle to be concerned about.
Listen to the engine,, check for excessive exhaust smoke.. check how it holds up under acceleration,, feeling if the transmission shifts accordingly and smooth. (don't forget to check reverse). Visually inspect engine compartment for rodent damage of tell tale signs of overheating,,, rusty residue along fender wells and engine.If you are not mechanically enclined have a friend or a certified mechanic look over the mechanicals of the RV.
The idea of buying a used RV over new, is the cost. If the unit needs repair, take into concideration of how much you want to invest into rebuilding/ repairing. What you can or cannot repair yourself.
You will never actually get back everything you invest into your RV. It is a labor of love.
And, remember when your buying USED,, It's NOT going to be everything brand new and flaw free. Its especially true when buying a vintage trailer to restore. Its the fun of bringing a classic back to life and feeling good about doing the whole process yourself. Then standing back and saying ,I DID THAT. With blisters on your hands and sweat on your brow, You took something that was old and made it new with life again.
This is just a rough pre check to looking at purchasing a used RV.. There are tons of info in the forums that can and will help you along.
Happy camping and remember the memories.