Jump to content
Sign in to follow this  
John E Davies

Sacrificial zinc anodes on the frame ..... checking and replacing..

Recommended Posts

First, here is a tech bulletin offering basic info and instructions to inspect annually. No other useful info about actual replacement is included.

 

http://olivertraveltrailers.com/topic/tsb-understanding-galvanic-reaction/

 

How many zincs are there on an Elite II frame?

 

What are their exact locations?

 

What is the correct procedure for replacing them (surface prep especially)?

 

Are they in fact zinc, or some other metal such as aluminum?

 

What is the size and part number?

 

Would it be beneficial to add more to the frame? Or larger ones?

 

http://www.boatus.com/boattech/casey/sacrificial-zincs.asp

 

There are two reasons I am asking:

 

First, they should be inspected annually and replaced if eroded to 50% of their original size.

 

Second, I will be adding additional aluminum brackets to the frame and wish to add extra zincs on them. Two of the brackets are for mudflaps and they will be in a harsh location in terms of road spray and gravel rash..

 

Comments?

 

Would somebody with direct experience like to start a How To thread? Any and all comments are most welcome.

 

Thanks.

 

John Davies

 

Spokane WA


"Mouse":  2017 Legacy Elite II NARV (Not An RV) Two Beds, Hull Number 218, See my HOW TO threads: https://olivertraveltrailers.com/topic/john-e-davies-how-to-threads-and-tech-articles-links/

 

Tow Vehicle: 2013 Land Cruiser 200, 33" LT tires, airbags.

Share this post


Link to post
Share on other sites
John I found this on the web and as it is applicable to trailers thought it may be informative. The heavy aluminum frame of the Oliver and the contact points with the leaf springs brackets would seem the likely surface that would be in contact and have occasion to have an electrolyte ( water and winter salt) creating a circuit setting up some galvanic corrosion. These points of contact would also be subject to corrosion without electrolyte if not electrically isolated by use of fay surface type sealant . The bolt/bushing of the leafs contact is likely to be the non protected pathway in the frame. I’d like to know the placement of the zinc’s on the Oliver as well. My thinking on this is that the trailer is not submerged like a boat in an electrolyte as a constant state and therefore the rate of corrosion would be low and the zinc’s would have long life.  

Thanks for the article.

 

I hope nobody is submerging their Ollie into salt water, but winter deicing chemicals are JUST as bad in terms of potential corrosion, and the problem is that they are hygroscopic (never dry out) and it is often impossible to wash a trailer in freezing weather. This is one reason I won't even consider towing in the NW this time of year.

 

BTW I do intend to electrically isolate each aluminum mudflap bracket where it bolts to the steel subframe.

 

John Davies

 

Spokane WA


"Mouse":  2017 Legacy Elite II NARV (Not An RV) Two Beds, Hull Number 218, See my HOW TO threads: https://olivertraveltrailers.com/topic/john-e-davies-how-to-threads-and-tech-articles-links/

 

Tow Vehicle: 2013 Land Cruiser 200, 33" LT tires, airbags.

Share this post


Link to post
Share on other sites

When bolting something to your aluminum trailer, don't use stainless steel bolts.   I've had enough experience with this around boats. The aluminum corrodes severely and turns to dust, while the fasteners are fine.

 

Galvanized bolts work fine.  After about ten years or so, you may find the galvanizing is gone in some spots, but the aluminum should be mostly fine

 

I just replaced my coupler with a new 2 5/16" Bulldog coupler.  There was no sign of any corrosion where the steel was bolted to the aluminum or in the cad plated, grade 8 bolts.  Only about 2 1/2 years old, but no sign of a developing problem.  The coupler is an interesting place to look too.  There is a lot of force there.  So much in fact, that it had slightly elongated the holes on the old coupler where the grade 8 bolts went through.  It's also exposed to dew, rain, snow and road spray.

 

Also, I don't know the particular aluminum alloy that Oliver uses.  Some aluminum is much more inert or corrosion resistant than others.  Some aluminum corrodes quickly when exposed to salt water, for instance, and some is used for boat hulls that are left bare and used in the ocean.

 

I'm actually more concerned about the frame welds than I am about the frame's structural tubing.


John


"I only exaggerate enough to compensate for being taken with a grain of salt."


LE2 #92 (sold),   Black Series HQ19   

Share this post


Link to post
Share on other sites

While I agree that stainless bolts can be a problem, look under your Ollie and you will see that the body is bolted with stainless bolts through the frame rails.

 

If you use aluminum anti-seize compound on the fasteners, they should be fine. I agree that sticking them in there unprotected is possibly bad news. I wonder if the factory coats them?

 

OTH I have removed bare stainless bolts from a 13 year old aluminum trailer and found only a light white coating.

 

The best defense is keep the electrolytes away entirely.

 

John Davies

 

Spokane WA


"Mouse":  2017 Legacy Elite II NARV (Not An RV) Two Beds, Hull Number 218, See my HOW TO threads: https://olivertraveltrailers.com/topic/john-e-davies-how-to-threads-and-tech-articles-links/

 

Tow Vehicle: 2013 Land Cruiser 200, 33" LT tires, airbags.

Share this post


Link to post
Share on other sites

Looks like anodes on both sides of Ollie's steel Dexter axle shackle bracket. I need to clean, prime & paint Ollie's steel axle shackle brackets, too.

 

IMG_1112-L.jpg

 

IMG_1113-L.jpg

 

 


Bill

LE2 Tundra

 

Share this post


Link to post
Share on other sites

John,

 

Be careful using aluminum anti-seize on stainless fasteners.  Aluminum "anti-seize" turns into "seize"  as the aluminum in the grease reacts with the stainless (the very thing you are trying to prevent by isolating the stainless bolts from the aluminum frame).   It expands, turns to powder and locks the threads.  I think this also makes the stainless bolts more likely to gall, which means they will never come apart and will have to be cut off.  This is another lesson from being around a lot of boats.

 

Copper based, or nickel based anti-seize is better.  Even a good coating of Teflon pipe dope is better as it prevents water intrusion and lubricates the threads.  I have also used silicon caulk.   It works very well and also acts as a mild thread locker, if you need that function too.

  • Thanks 1

John


"I only exaggerate enough to compensate for being taken with a grain of salt."


LE2 #92 (sold),   Black Series HQ19   

Share this post


Link to post
Share on other sites

"Looks like anodes on both sides of Ollie’s steel Dexter axle shackle bracket. I need to clean, prime & paint Ollie’s steel axle shackle brackets, too."

 

 

 

Bill,

 

I've seen those too.  But I assumed they were simply alignment reference points for the suspension truck.  Are they zinc?


John


"I only exaggerate enough to compensate for being taken with a grain of salt."


LE2 #92 (sold),   Black Series HQ19   

Share this post


Link to post
Share on other sites

Bill,

 

Thanks for that!   Sure enough, and I did not see the one up on the tongue.  It will be fun to see what happens to them over time and If any corrosion shows up on the aluminum.


John


"I only exaggerate enough to compensate for being taken with a grain of salt."


LE2 #92 (sold),   Black Series HQ19   

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×
×
  • Create New...