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Chris - Roadmaster chassis

Chassis maintenance tips for spring

It doesn’t matter what type of RV you have, you have a chassis (or two) to think about for maintenance, and with a little forethought and planning, your RV will be ready and safe to use at a moment’s notice.

The chassis we refer to is the running gear of the RV — where the rubber meets the road. Now for those of you who have seasonal trailers set up permanently on a site, you don’t need to worry about this stuff so much. For you truck camper owners out there, your pickup truck is your chassis so this certainly applies to you.

The chassis includes the frame, suspension, hitches, powertrain, fuel systems, DOT lighting and the wheels and axles.

For clarity, I am breaking this into two sections: motorized and towable. Motorhome and truck camper owners have one chassis to deal with, whereas trailer owners have two; one on the RV and one on the tow vehicle.

Chris - Class A chassis

Motorhome chassis

This is a quick overview of motorized chassis service, and is not intended to replace the maintenance recommendations offered by your chassis manufacturer in the owner’s manual. Always follow those to ensure maximum reliability, safety and length of service for your equipment.

When you are driving a motorhome or hauling an RV, your powertrain is under a substantial load, and in many cases is operating at its maximum capacity. As such, following the manufacturer’s recommendations for heavy service loads is required.

Make sure you change your oil at least once a season, preferably before storage. Motor oil builds contaminants and acids as it is used, so if you’re only using your RV occasionally and don’t meet the requirements under mileage, use the time recommendation instead. Always try to store your RV with clean oil. Use a good quality oil and filter as recommended by the engine manufacturer. Don’t forget your fuel and air filters as well.

Make sure you have your transmission serviced per the manufacturer’s schedule. I say this because many motorhomes are equipped with Alison transmissions which have their own service requirements. Don’t skimp here either…remember you’re putting a constant heavy load on the transmission so take good care of it.

Keep your chassis lubricated. Some big coaches will have dozens of grease fittings that have to be kept greased. If moving parts aren’t kept lubricated, you’ll have dry parts rubbing against each other which inevitably leads to problems.

Brakes and bearings should be looked at annually at the minimum, even if the coach is stored for long periods. Brakes slides can corrode, calipers lock up, etc. with long term storage and moisture corrosion. Air brakes must be inspected annually to make sure the adjusters are operating properly, and all brakes should be inspected for wear.

Your tires are literally what keeps you on the road, and yet are the least thought about. We’ll do a whole article on tires next time, so stay tuned!

You folks with the diesels need to also think about your air system if you have one. Your coach will be equipped with an air dryer with a replaceable filter. Make sure you service this according to that manufacturer’s recommendation. Also you will need to test your coolant for DCA level, or Diesel Coolant Additive (also called SCA.) All diesels need additive to prevent cylinder wall damage from pin holes forming as a result of cavitation. DCA is available as a liquid additive, and is also in coolant filtration. Special test strips are available to check the coolant to maintain optimum DCA levels.

You should be checking your lighting before every trip to make sure everything is working as it should, but spring is a great time to so it as well.

If you have hitches and hitch/lighting and braking assemblies for trailers, towed cars, etc., go through them all carefully. Make sure everything is lubricated, the cables are in good condition, and that everything works as it’s supposed to. Touch up the paint to prevent rust from forming.

The frame of your chassis should be kept clean and as rust free as possible. Unfortunately the coatings (paint) on any frame aren’t the quality of the body paint, so rust can be an issue. Once cleaned and scraped, Rustoleum gloss black has always worked well for me to make the frame look great and stay that way.

Chris - Fifth wheel chassis_render

Towable chassis

The same emphasis on maintenance for motorized chassis must be put on trailer chassis, although there is technically less to deal with, it’s still very important.

A visual inspection of your hitch gear is extremely important before every trip to look for damage, but in the spring it’s wise to take a closer look. Clean your hitch equipment and remove any lubricants and look for damage. If you suspect something is wrong, contact your dealer or the hitch manufacturer for guidance.

Chris - Hitch systemAfter you have cleaned and inspected everything, touch up the paint as needed. Remember this isn’t just for looks (of course that’s important too) but it’s to keep rust from having its way with the hitch. Once the paint is dry, lubricate all the moving parts as recommended by the hitch manufacturer.

Fifth-wheel owners should look at the pin and pin box carefully for odd wear patterns on the pin, as an example. I highly recommend the pin lube plates, but add grease to the pin in addition to the lube plate.

Tow behind owners should make sure the locking assembly is free and moving well, the whole hitch assembly is bent or twisted in any way. Weight distributing hitches should also be checked for problems, paint toughed up, and the ball check for wear. Remember you must lubricate trailer hitch balls (unless they’re the lube free kind.) Otherwise it’s a huge amount of grinding pressure on that small point, and you will see accelerated wear on the ball or even ball failure.

There are a number of different kinds of trailer suspension systems out there. Some are maintenance free, some have no ‘maintenance’ but need to be watched for wear and some have zerk (grease) fittings. Your owner’s manual will have more information on your particular setup.

The most common towable RV suspension is the standard leaf spring suspension. Most of these have ungreased shackle bolts. The shackle attaches the spring to the frame or to the equalizer in the case of multiple axles. Wet or grease able shackle bolts reduce this kind of wear. If their non-serviceable (grease able) they should be removed after five years and inspected and/or replaced.

Brakes and bearings need attention regularly, and spring is the perfect time. Here’s the schedule:

  • Bearings should be repacked at 12 months or 12,000 miles, whichever occurs first. Bearing seals must be replaced and the bearings cleaned and inspected for discoloration and damage. I prefer to use a bearing packer to repack the bearings (a few bucks at Harbor Freight.)
  • Brakes should be inspected and adjusted:
    • Every 3,000 miles (unless they are self-adjusting brakes)
    • Annually
    • Or if decrease in braking efficiency is noticed

A sure sign of a problem on a trailer is odd tire wear. It can be caused by a simple misalignment of an axle, but can also be worn shackle bolts, loose hub, overloading or a bent axle. To prevent a tire blowout and all the resulting damage, have tire wear problems looked at immediately.

We’ll talk more about tires in the next installment.

The frame should be kept clean and as rust free as possible. Remove loose rust and then paint with a rust-preventive paint like Rusoleum gloss black. Lubricate all moving parts like jacks and steps.

Until next time, safe travels and Let’s GoRVing!

About Chris Dougherty

Christopher Dougherty, "The RV Medic", offers service advice and maintenance tips. Dougherty is a certified technician who has written for several other RV publications in the past. He also serves as a consultant to the RV Industry Association and other RV groups on service-related issues.

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