Trailing Arms Cracked on Roadmaster

[Jim Stewart]

I had mine replaced preemptively. I did notice less porpoising after replacement. I would liken it to both dampening and rebound on shocks. The Source Arms are stronger and would appear to be less flexible. Dampening is how hard is the initial bounce and then rebound is how long does it take to stop bouncing up and down after the initial bounce.

Until I read your post, I did not stop to contemplate how one would notice, and do not know if it is possible to determine, if the difference in ride would be an indicator of impending failure. The only measurable factor I am aware of would be ride height. It would not change prior to failure unless it was cracked so bad that it drooped, that would be visible on simple inspection.

I suppose that poor shocks could be a contributing factor to failure, allowing more initial bounce and longer stabilization after the initial bounce which would place greater stress on the arms as they flex. In addition a single side failure would make it more stressful on the opposite side due to unequal rebound.

Sorry to ramble, the answer is, there is probably not a measurable indication prior to failure.

[Flagelpater]

I should have been more descriptive, sorry. I was thinking of a measurement between two points. Or a profile template. Something that would show a change. Maybe a rod or stick with marks on it that can be placed up against the arm. I do not think it will work other than directly on the arm. I agree ride hight shows up at the time of failure but probably is not discernible prior to total failure. When both of my arms failed the front end also went down to maintain alignment, the coach was Level.

[Jim Stewart]

I'm not an Engineer, not even really that bright! That being said, the arms break right at the joint with the mounting plate that is welded to the arm (see picture) I would assume that the angle may change slightly with the fatigue and flex prior to cracks or failure (maybe not).

You might be able to measure the angle/relationship and if it changed at all, it may be a warning sign. I doubt that it is possible to detect or measure that minor of a change, but all things are possible, the Health Care Plan did pass in the House of Representatives!

[jamorton]

So many bad things in life come as complete surprises. You have no warning before someone runs a red light and smashes into your vehicle. You may have no warning when some health crisis occurs and threatens your life. If you have an affected chassis and are reading this thread, YOU GOT A FREE WARNING! ! Be thankful that you can consider what you want to do with the information you have gotten. I would suggest that you not waste this info. I have lived through the failure of one of these arms, it was sudden and unexpected and radically affected the handling of my coach.

Regarding the cost... hmmmm These arms are used on coaches with a retail price on the order of $150K. My repair totaled $3,700. That is 2.5 percent roughly. Seems like a no-brainer to me. Of course, I had no choice - my trailing arms failed before I was aware they even existed. If my extended warranty company did not cover the repair, my rig was going to be parked a very long time - $3700 is a lot of money in this economy. As for the cost of the pre-emptive repair, I suggest that if you can possibly afford it, do it, your health and safety is most important, not to forget the likelyhood of additional damage if the thing fails when you are underway at speed.

As far as Source Engineering, and their price, the $1800 (marked up by my RV repair shop which is not a stocking dealer) seems entirely fair to me. In any case, the price is published and is not a "how much can you bear" situation.


Happy Trails !

[edsalzer]

Jmorton,

Well written. An ounce of prevention is worth a pound of cure. Always SAFETY FIRST.

Thank You

Ed

[Nonno]

New arms are installed!!

In preparation for winter, MH will be parked so I can't report on ride improvement until our trip to FL in Feb. However, I can report that even though the trip from the dealer to my house was only 20 mi, for the first time in months I didn't have to worry about the trailing arms failing.

Parts & Labor paid by extended warranty $2620.
Deductible & freight paid by me $424.

Special thanks to Ed & Jim for what you have done to alert me of the problem and the solution.

[Jim Stewart]

Nonno,

Like your end result price! I think you will find that the ride improves as well, especially the porpoising! Have a safe trip to my home Statex2.

[Nonno]

Jim, Ed & others with the new arms.

Anyone know if the accuracy of the ride height measurement is as critical with the new arms? Installation instructions state "When finished check the bag height, it should be 9.0" plus/minus .5" However, the rear measurement I got last year from Monaco was 8.5" and if I recall correctly some reported that as little as 1/16" made a big difference on ride quality with those OEM arms. Dealer told me mine are now 9"

[soberjoe]

This is an interesting question. I'm surprised we don't have some comments on this yet. Can you really feel a diffrence in the ride from a 1/2 inch change? Seems like it might be more in our head then our butt.

[Jim Stewart]

The point of measurement, eyesight and angle of the dangle could make it off by 1/16 of an inch. I doubt the 1/16 would make any difference.

[walt2137]

Originally Posted by Nonno

Jim, Ed & others with the new arms.

Anyone know if the accuracy of the ride height measurement is as critical with the new arms? Installation instructions state "When finished check the bag height, it should be 9.0" plus/minus .5" However, the rear measurement I got last year from Monaco was 8.5" and if I recall correctly some reported that as little as 1/16" made a big difference on ride quality with those OEM arms. Dealer told me mine are now 9"

Just remember that ride height increase will increases the drive shaft angle and that is not a good thing, If it was me I would stick with the 7" front and 8.5 " rear or maybe less but not more.
Monaco has had a drive shaft issue on some of the newer coaches.

[Myoung]

Originally Posted by soberjoe

I say thank God for free markets. They are going away with each passing day. I'm very thankful Source is there and they saw a need and made a product to meet that need. So far they are the only game in town so they can charge whatever they want. I have no problem with that and in fact I strongly support that. We are free to buy or not buy their product. I don't plan to buy their product, (reinforcing my arms w/more steel) but I sure say thank you to Source for making a choice possible.

If you were to contact Roadmaster they will refer you to Source & if you cantact Source, they would refer you to the dealer closest to you & will not sell them direct. I work for a repair facility in Eugene, Or. & have installed these kits on to a few coaches. Source or its authorized dealers is actually not the only place to get these upgrade kits eather, but not many people know this.

The following is a list of the affected models & year range:
2002-2004 Monaco Knight
2002-2009 Monaco Cayman
2002-2004 Holiday Rambler Ambassador
2002-2009 Holiday Rambler Neptune
2002-2006 Safari Cheetah
2002-2005 Safari Zanaibar/Sahara
All Years Safari Simba RD
All Years Beaver Baron
or any other coach with a Roadmaster 8 bag air ride system.

[Ultra RV Products]

Source Manufacturing's Arm's have liability insurance & are Patent pending, they are a proven, high quality product. Becareful of low quality non insured knock off's, that may give you trouble down the road!

[Nonno]

or any other coach with a Roadmaster 8 bag air ride system

4 Bag not 8 bag