Truck and Trailer Revival

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November 3, 2008

With the economy being what it is, we are seeing more and more RV owners choosing to hang on to their rigs and fix them up, rather than trading up for something new. Realistically, it just makes sense-because for the cost of a couple of payments, you can often make your rig as good as new-or even better in the case of a customer’s rig we have in our shop right now.

He owns an ’02 International 4700 medium duty truck towing an ’02 Travel Supreme triple-axle fifth wheel. The truck has over 115,000 miles on it, and recently returned from a trip to Alaska where it was driven over some pretty rough roads. The customer complained about a rattling noise, and that it was riding “heavy”. The rear air suspension was taking a long time to level out, and he indicated that he was having difficulty keeping the truck in its lane.

Well the original shocks had seen better days, and not being able to fit Road King shocks on this particular truck, we went with Koni shocks instead. This made a huge difference in the way the truck rode. Upon further inspection, we realized the cause of the leveling problem: The rear air suspension was not equipped with an air dryer, and the leveling valves and relay valves were loaded with moisture. This is a fairly common problem on trucks like these that have air suspension, but not air brakes; air brake trucks move enough air so that the manufacturer feels an air dryer is justified. Without an air dryer, the water tank must be drained at least every month or so to prevent water from collecting in the system and you’ve got to crawl under the truck to do it. So we replaced his compressor with a rebuilt one (there was evidence of oil in the ride height valves, too-caused by a compressor that’s going bad), installed new ride height valves and an air dryer to prevent moisture build-up in the future.

Wander is a common problem with straight-axle vehicles, and they often don’t return to a positive center. To combat this problem, we installed a Safe-T-Plus steering stabilizer. In case you’re not familiar with this product, the Safe-T-Plus is a hydraulically dampened,mechanically self-centering device that keeps the vehicle tracking straight. Because it’s self centering, it also greatly reduces rut tracking, where the tires follow grooves in the road. And finally, as I’ve discussed in previous posts, it can even improve mileage and reduce tire wear. How? The less you are working the steering wheel, the less resistance you are creating and the less scrub on the tires.

The owner is now thrilled with his truck, which rides smoother and tracks straighter than it did when it was new. In the next post, we’ll talk about some of the major improvements we made to the fifth wheel as well.

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  2. Ann

    Do you have any suggestions to improve handling on a 1991 Roadtrek Popular Class B camper van? It has 50k miles on it, and we are planning to replace the shock absorbers this season.

  3. Hello Gentleman,
    Thank you for the excellent comments. I must agree with you about the pull cable type of drain. I thought about that after I had already finished the post. I should have mentioned it. Good catch. This customer is interesting in making his truck better than new and is very happy having the dryer. It is not a bad idea to periodically drain the tank even with a dryer. You may be surprised to know that many of the motorhomes on the road do not have drain valves on them. I personally like to have both the drains and the dryers.
    There are some good buys to be made out there on new & used vehicles . However, whenever I buy a different vehicle I usually wind up spending quite a bit to get it where I want it. So before you buy you may want to find out what you could be looking at to set it up the way you like. A competent specialist (or other fellow RV’ers who have the same rig) may give you some ideas about the possible areas of concern to look for by doing an assessment of the vehicle before you buy. You might possibly also use this for further negotiations on the purchase price.

    Safer & Happier Driving , Robert

  4. John Shelton

    I wish to ‘pick a point’ concerning air dryers on air compressor equipped vehicles. There is a saying among mechanics in the truck trade that goes something like this: “You can drain your air tanks daily, and you will not have any air problems; or you can add a $500 air dryer and drain your air tanks daily, and you will not have any air problems.” Cable-pull air tank drains can be installed on air tanks that permit easy draining from outside the vehicle without having to crawl underneath to drain. Air dryers should not be expected to totally prevent any accumulation of moisture in a truck air system. They only REDUCE moisture accumulation and regular air tank draining is still a required maintenance item on air compressor equipped vehicles.

  5. Sid Burklund

    I agree with all that you said – but – lets not forget that the economy has given us the best discounting the industry has seen in years. While we are keeping our 2006 F-250 6L Turbo Diesel 35,000 Mi. even though the dealer is pitching some sweet deals our way if we move to a new rig.

    For our RV, we have been pulling a 32′ Komfort, fiver for the last three years and loved it very much. But – on kicking the tires on 2008 inventory on several lots around here and given the discounts being offered we decided to move to a larger fiver. We just closed on a new 2008 37′ Komfort and feel we got a great deal and did the right thing for us.

    So! I agree with all that you said but point out that there are some options to be had if you look around and take advantage of the deals being offered.

  6. I have a 2000 4700 with 84,000 miles, we love it and it rides very well with 5er behind it, also pull a Honda on dolly behind the 5er. I have made some changes to the air ride on back axle which makes it ride a little better when solo. MDT’s are great trucks for pulling large 5er’s for fulltime RVing.