Metal Fatugue of Stone Guard

Suncircles · 01-31-2009, 07:16 AM

I want to report a chassis problem which could have resulted in tire damage if I hadn’t noticed the problem. The propane tank is located on the curb side of my 2005 Journey 36G. The tank is just forward of the rear tires. Winnebago installed a stone guard plate between the rear tire and the propane tank for obvious reasons. This 11” X 18” powder coated plate is spot welded to an L bracket and bolted to the Freightliner chassis with three nuts and bolts.

Traveling down I-40 through Oklahoma two weeks ago, my DW heard a rattle she located in the area of the rear axle on the curbside. Upon inspection of the area in a truck stop parking lot, I found that the rattle was coming form this stone guard plate. Despite the fact that the plate was still firmly bolted through the L-bracket/plate interface to the chassis, the plate rattled back and forth. Removal of the plate showed that there were metal fatigue cracks running from both edges of the plate along the edge where the L bracket and the plate met. The cracks ran in from both edges about 4-5” and it is only a matter of time when the two cracks would join up, resulting in the plate falling off and, possibly, into the tires just behind them. I assume that the plate failure is due to high air turbulence in that area which was “working” the metal plate back and forth until it cracked due to metal fatigue.

Since it is a Winnebago modification of the chassis, this part is no longer covered by any warranty and I had to pay $50 plus and $10 for shipping to replace it with a duplicate plate. I asked Winnebago service if they had a technical fix for this apparent problem. The representative was not aware of this problem, but suggested that I install the new plate with additional support brackets. I am presently trying to figure out just how to engineer such bracket(s).

Have others noticed this problem? Does anyone have suggestions on how to keep the new plate from failing just like the old one did? My coach has only 12,000 miles on it. I would like to suggest that physical inspection be made of your coach, just in case you might be having the same problem.

Suncircles

MaverickBBD · 01-31-2009, 09:01 AM

Thank goodness your wife has good ears and you were able to track it down. I too would agree that the likely cause of the crack would be from either air turbulence and/or vibration BUT I was wondering if the plate and the bracket are dissimilar metals. Was there any sign of corrosion?

Suncircles · 01-31-2009, 10:04 AM

MaverickBBD:

Yes, vibration could also contribute, but I believe that air turbulence is the primary culprit. A design flaw for sure.

I believe the metals are similar. The cracks on both sides start on the edges just below the points where the two components meet and propagate up to the interface and then along the interface toward the center. I believe these start points result from a high stress line across the plate where the most flexing occurred while the plate was wagging in the wind.

As for rust, rust appears in the cracks (therefore the plate is iron-based), but because of the powder coating, there are no other rust spots on the plate or the L-bracket.

I believe everyone should check their stone guards.

MaverickBBD · 01-31-2009, 10:35 AM

I am definitely going to take a close look at mine today as I have the exact same coach. Will get back to you with what I find. Thanks for the heads up.

MrTransistor · 01-31-2009, 10:52 AM

Hello Suncircles,

We had this same problem on our 2002 Journey. At certain speeds the plate would vibrate like crazy. Problem solved with an additional bracing bracket before any cracks appeared. Too far in the past to remember the details of the bracket. Homemade and simple is all I can remember.

DonGee · 01-31-2009, 02:58 PM

Should you consider reporting to the NTSHA ? Seems to me this is a safety issue and should be on a recall.. I think it is past time for the manufactuers to accept responsibility for inferior workmanship or products under built to save a few pennies.

wagonmaster2 · 01-31-2009, 06:52 PM

My wife also picked up a noise she kept saying was coming from under the shower, which is directly over the LP tank. I had to re-do something about the Guard but its been too long ago to remember exactly what I ended up doing. I also had to add additional bracing to the Passenger-side rubber mud flaps to keep them from flapping the storage box just behind them, which made a terrible noise driving in a hard wind. I begin to wonder if Winnebago engineers have ever ridden in, driven, or camped in an RV. Kind of like some of our auto engineers.

Instead of trying to replace the Guard with another one of the same quality, take the old one off and take it to a good welding shop. They should be able to re-weld the cracks then add additional bracing to keep it from re-cracking. I have a welding shop who has made me a riser for my hitch receiver, a tow bar bracket for my Wrangler, and re-done one of my slide-out supports on the storage box. And they are always much better made than what I've seen in the RV stores or ordered as replacements.

Wagonmaster2
2004 Meridian 36G

theroc · 01-31-2009, 07:07 PM

The guard on mine seems secure right now.

However, I've had a question on whether it is normal for it to be so close to the tires. There is less than an inch clearance.

I wondered about this because I travel occasionally in the mountains in the west during the winter where in some states, chains are required to be carried. I've always wondered whether I should even buy them to carry because there is no way I could actually install them on my coach on the right side because of that guard. Even cable chains would be iffy.

I don't mean to hijack this thread but since we are on the subject of this guard, could somebody quickly tell me if it is supposed to be so close to the tires themselves?

I have a 34H '07 Meridian. Thanks.

tomsm · 02-01-2009, 09:10 AM

I had that problem practically from day one. There was a thread on here several years ago about the same thing. Someone mentioned an inelegant (his word, not mine) fix by tying a heavy piece of wire through one of the holes at the bottom of the plate, leading the wire forward, pulling the wire enough to bend the plate slightly forward and then tying it off in the LP compartment.

I'll also say it's not elegant, but it works so well that after doing it several years ago, I had totally forgotten about it...

smlranger · 02-01-2009, 09:21 AM

You folks have me curious. While we have an annoying squeak that seems to be coming from the wall near the front passenger seat, no rattles or vibrations from the rear. I will check on that plate...I've been under and all over the rig but just cannot seem to remember anything special in that area.

tomsm · 02-01-2009, 09:51 AM

It's a plate that separates the rear wheelwell and the LP compartment. Looks like it's intended to be a stone-shield for the LP tank. Maybe you're one of the lucky ones that doesn't have the flex or maybe the previous owner removed it...

theroc · 02-01-2009, 10:22 AM

It appears that most of you have a 36 footer. Anybody with an "old style" 34H have an answer to my question if this guard should be so close to the tires? ...less than an inch between the guard and the tires.

I'm assuming it's normal in a 34H because it seems solid as a rock right now. I guess I'm also assuming that it's further away from the tire in a 36 footer.

I'm hoping mine will stay "solid as a rock" for that seems better than my worrying about putting chains on the rig!

Do you guys think it would be a wise idea to remove it?

Thanks.

JC2 · 02-01-2009, 10:47 AM

On our rig, we have the metal guard flaps mounted in front of the rear duals at a distance of about 3-4 inches. Each of the compartments in front of these however are for storage. Our LP tank/compartment is to the rear of the pass side and has a heavyduty rubber flap mounted to the frame with heavy metal stripping as is the driver side. You might consider replacing the metal plate(s) with a heavyduty mudflap.

I would be concerned if your clearance is only 1 inch.

smlranger · 02-01-2009, 12:41 PM

Quote:

Originally posted by tomsm:
It's a plate that separates the rear wheelwell and the LP compartment. Looks like it's intended to be a stone-shield for the LP tank. Maybe you're one of the lucky ones that doesn't have the flex or maybe the previous owner removed it...

I just checked and I have no shield. From the LP compartment, I can look directly at the rear wheels. I can see where it looks like something was spot welded to a brace above and either fell off or was otherwise removed.

I guess the thinking was a rock caught between the duals could be thrown at the tank...not likely but possible.

theroc · 02-01-2009, 12:55 PM

Ok, so would it be the consensus that the guard could be removed and not cause a great deal of worry that the propane tank could get damaged by something thrown off the duals?

I'm tempted to take it off completely so I can run with chains in the event I absolutely had to. Right now, with less than an inch clearance, I wouldn't even attempt to put cable chains on the right side.

skigramp · 02-01-2009, 01:29 PM

This thread encouraged me to do some looking under my rig ... I discovered

a) the sound that we hear when driving into a wind quartering from the curb side is the rubber mud flap hitting the bottom of the storage bin behind it ... it is bothersome ... but it seems to be doing no damage

b) there is a metal shield between the rear dual and the LP tank compartment ... it is fairly close to the tires but shows no sign of ever touching the tire and no cracks

Tire chains on a motorhome? ... I am retired so I would park it and wait for the roads to clear

fun time · 02-01-2009, 02:09 PM

We have 2 Journeys and 3 Meridians in our park where we hare staying. Today I checked two 2006 36Ft. Meridians and both guards are 3-4 inches at least from the wheels and show no signs of movement or cracks. Tomorrow, I will check the Journeys to see if there is any difference and report back.

wagonmaster2 · 02-01-2009, 05:18 PM

skigramp - I too hated the sound of the mud flaps hitting the luggage box behind it in the wind which happened to me the first trip out west with a new coach. Thought something was flying apart. When I got home I took some metal strips about an inch wide and 1/8" thick and cut a couple for each flap about 12-15 inches long. Drilled a hole in one end of each and fastened it to the bolts through the outer ends of the flat letting it hang down the rear side of the flap. It just made a brace for the flap to flap against instead of the box. Sprayed them flat black before installing, they don't show, and 3 1/2 years and 30,000 miles later - no more noise.

Wagonmaster2
2004 Meridian

Hooligan · 02-01-2009, 05:52 PM

FWIW: The shield may not be just for rocks. My 1990 Class A had a blow out on the right rear tire, part of the tread or steel belt bent the angle iron and brace in front of the wheel well into the back of the propane tank, and damaged the side panel at the fwd edge of the wheel well. The tank was not damaged. The tire started thumping just before it blew and I was down to less that 40mph when it let go.

theroc · 02-01-2009, 07:26 PM

Oh wow, thanks Hooligan.

hmmm, yeah, I don't think I want to remove the guard now thinking about it. They must've put it there for a reasonable purpose.

I just can't understand why mine is so close to the tires.

fun time, if you see a 34H in your park, please report back as to how close the guard is to the tires. There used to be quite a few 34H owners here on the forum but maybe they've all sold and upgraded.

And skigramp, yeah, me too. I'm retired and just as soon wait it out but in the west some states require heavy vehicles to carry chains whether needed or not during the winter. I figure as long as I'm going out to buy them, they might as well fit just in case but like I say, with that guard there, there is no way I can put even cable chains on the right side.