Ever heard of Galvanic Corrosion? - Montana Owners Club

PAIC 01 · 10-24-2006, 05:18 PM

I purchased a 2006 Mountaineer 336RLT last March and I found the wrap-under side panels have rusted through at the mounting points. I have been advised today by the dealer, that Keystone will NOT cover the damage as it is climate related. The unit was delivered to the dealer in December of 2005, and I purchased it in March 2006. I took the unit home (250 miles) (dry roads and sunny day), and it was parked until we used it next in June 2006. (WHAT CLIMATE!)
Which brings this point from my research: Galvanic Corrosion is a result when two (2) dissimilar metal are joined together (ie: aluminium wrap-under and steel frame) with metal bolts,screws etc. When you add a power source (ie:battery negative cable attached to the steel frame) and when you add electrolyte (ie:water, condensation) the charge will go to the weaker metal (aluminium) and will eat at it until the panels fall down.
Please correct me if I am wrong, but my Monty is eating away as we speak and the company says it's the "CLIMATE".
One possible way to rectify this, is add a sacrificial anode (like I have on my boat). Another way, is to put plastic or rubber bushings between the panel and the frame as well as the panel and bolt head in order to stop the conductive energy.
Has anyone else encountered this phenomena on their unit? If so, has Keystone repaired it under warranty?
I was so anxious in purchasing a new Montana as I believed they were one of the best, but now I feel I've been fooled in thinking so.
I hope not, because I still love this 5th wheel, but not for too long, it's rusting away!!!!

Giddyup!

jpp

Ozz · 10-24-2006, 06:12 PM

Wow!
I heard about a small electric current being used somehow to reverse the effect, maybe our resident engineer-(Bow Tie) sorry, I do not remember your 'Handle'
Also, I would be suspect of a voltage leak somewhere into the frame, this deal smells like a rotten fish, I think the dealer is missing something here...........
Ozz

steves · 10-25-2006, 01:50 AM

Suggest you eliminate the dealer and communicate with Keystone yourself!

richfaa · 10-25-2006, 02:23 AM

Gm had that same problem in the mid 70's.It caused rear bumpers to fall off, as I recall Pontiac's and Buick's.We had a 77 Pontiac that the rear bumper fell off. There was a recall and GM repaired and replaced at no cost. I would pursue the matter with Team Montana.Someone will come up with a number..

PAIC 01 · 10-25-2006, 02:26 AM

I called the dealer this morning, and I guess it will be MY problem to deal with Keystone. The dealer will put fender washers over the holes. Too late, it's already been done! I can remember reading sometime ago about a current discharge through metal, that would cause corrosion, but can't remember the detail and/or the fix. I am told that ALL trailers have this type of corrosion. My old Laredo did not and it was towed to Alaska and back. Talk about CLIMATE!
Thank you guys and gals.

Giddyup!

jpp

Steve and Brenda · 10-25-2006, 02:32 AM

JP, you tagged it right on the nose concerning galvanic corrosion. Dissimilar metals are always a problem when considering what metals to use in certain applications. Thats why we use gold instead of copper in critical electrical connections to reduce the oxidization.

Sounds like you were the first owner of this new RV and stored it for the season so no aluminum rust should have occured. Don't take this wrong but there's some questions needing answered to isolate the problem. Was the battery disconnected in storage? How many times was the RV used during this season? Have you made any electrical modifications to the vehicle? Is the rust in a particular area or the entire skirting around the vehicle? How many times was the vehicle washed with fresh water?

Aluminum alloys, likely what is being used in the RV's frame and trim, has a negatively charged potential and the low carbon steel chassis has a less negative charge potential, or a positive potential charge in reference to the aluminum. The differences in potential are very slight, within .02 of each other so they're a good mate for each other UNLESS there's a good amount of current flowing through the two metals. You also need an electrolyte such as water to cause the corrosion. If you live in the northeast where they salt the roads in Winter you're in ground zero for providing the electrolyte. I've never looked at the issue but I'd assume there's still salt in the roads all year long making wet roads corrosive all year long. Also, humid sea air can make a good electrolyte.

Based on my experience on aircraft you have one of two problems - a repair was made before delivery and the fasteners used in the repair were not the correct metals causing a galvanic condition or you have a bad ground. Look at the rusting areas and compare the fasteners to a nonrusted area - are the the same? If not, Keystone is responsible for the repair.

I think the central ground in the RV has a problem so the current is finding alternate paths to ground and I'd suspect the DC ground is causing the problem over the AC ground because DC needs that constant path to ground. Take a multimeter and do an Ohms check testing the connection between the battery's negative terminal and anywhere on the steel frame except the bolt where its grounded to the frame. You should get a reading of 1-2 Ohms or less. If you have a higher reading you have a grounding problem and Keystone is responsible. I'm going to do the same this weekend on my new RV just because its easier to fix a grounding problem than a corrosion problem.

You can clean the battery's grounding terminal on the bulkhead, bet there's some rust or paint preventing a good ground. Disconnect the battery, unplug the RV and remove and wire brush all three grounding points (I'm using my RV as a model and there's three grounds in mine). You can also look for an improper installation of a lamp circuit. if you turn on all your lights, both AC and DC, and a light appears to be dimmer than the others that light is tied to an aluminum ground instead of a steel ground in the frame. That one would be harder to trace but it would explain the problem.

As for reversing the existing corrosion I think the damage is done and is not reversable.

richfaa · 10-25-2006, 03:07 AM

I would do a print screen on the explanation by Steve and use the information when talking to 'Team Montana"

LonnieB · 10-25-2006, 03:42 AM

Steve, that is excellent information. I told you engineers are necessary.

Ozz · 10-25-2006, 04:10 AM

Thanks, Steve. Good explanation, you put into words what I had floating around in my brain somewhere.

CRUZIN 2 · 10-25-2006, 04:15 AM

Steve

Great post, lots of good info. I printed it out and I will keep it with my Keystone papers. Thanks so much.

Larry

noneck · 10-25-2006, 02:33 PM

This is odd as I have a 2002 Monty that has no signs of this corrosion. Aluminum skirt wrapped under unit over plastic belly pan and secured with steel self tapping screws into the steel "I" beam structure. I am pretty sure there is no leakage current as that is likely to be detected by my home shore power which I have fed by a 30 amp GFCI. This did "catch" a ground current problem. When I first purchased my unit I had a neutral wire that was rubbed through in the Dometic A/C unit generating ground current and hence tripping my circuit breaker...really fun debugging that one!

Chuck

Ozz · 10-25-2006, 03:53 PM

Chuck, those tasks separate the men from the boys. Good job.
Ozz

Garin1 · 10-27-2006, 02:16 PM

JP, You and Steve are in the right swimming pool there. As an industrial electrician I have had to install multitudes of aluminum cable tray to steel supports and we always install fiberglass pads between the two metals for exactly that reason. The potential for current will cause galvanic corrosion. Now, that means you have to look for a voltage leak somewhere. Get a good electrician to check your unit. Don't go around putting fiberglass bushings everywhere

Montana_6480 · 11-02-2006, 12:37 PM

Steve
Thank You so much for the detailed info. Is it OK with you if I share your explanation with Keystone Warranty service person?
Right now, I am waiting on him to get back to me.
INFO: The unit was delivered to the dealer in November of 2005, I purchased it in March 2006. I towed the unit home (250 miles) and did not use it until June 2006. I put approximately 500 miles on this trailer during the summer and hit the occassional rain we have each year but it was never towed during the winter months as I bought it new in March. The day I took it home, there was no snow on the ground and the roads were dry. Looking under the unit the rust damage is located at all mounting points from the front to the axle. The rear portion of the unit is free of rust. Looking under the passenger side of the unit, I see where a rusting hole is and someone moved the screw to another location nearby, like it had rusted through the panel and they just moved the screw in a new drilled hole. I have taken pictures of this damage and hope Keystone will make it good.
Thanks again

jpp

old turbo · 11-03-2006, 08:35 AM

If the unit was delivered in December of 05 it could have been on some nasty salty roads from Indiana to the dealer.Remember the unit was towed to the dealer, it could have looked like a salt block when it got there. A power wash will remove the exterior salt. If it got a lot of salt under the unit and it was not cleaned on the bottom side very well this could also cause some of your problems. The dealer could have had the units cleand again for the spring sale season and more of the cosmetic salt would be removed but not the stuff in the nuts and bolts areas.

Montana_6480 · 11-04-2006, 08:20 AM

Got the word yesterday from Keystone, and they will NOT cover the damage. They believe it's due to climate condition. I went and checked the 12V system as suggested by Steve, and the ohm meter does not show a bad grounding system. While checking, I did find a loose ground cable,ie: the ground for the hydraulic pump. I am still looking around, but it's getting too cold to roll around on my back, so I'll wait until we go south to finish it up. I will be keeping a close watch on the rust and hope it does not spread and I probably will be putting rubber washers in between the affected metals over the winter. You can bet that the next Monty I buy will be inspected head to toe, top to bottom and inside and out BEFORE I take delivery. I guess we live and learn. I still love our Montana, but now wiffy is talking motorhome! hemmmmmm! I wonder if I can talk her into a 30'-40' diesel pusher? Any pros or cons?

Giddyup!

jpp

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