Subject: LRO: Re: corrosion issues/shipfitters disease/sil

From: "C. Marin Faure" <[email-masked]>
Date: Tue, 15 May 2001 01:47:37 -0700

Date: Mon, 30 Apr 2001 10:51:00 -0700
From: SJH <[email-masked]>
Subject: LRO: corrosion issues/shipfitters disease/sil

>I recently pulled and refurbished the intermediate floor in my 109SW and
found some semi-serious corrosion at the extreme outboard ends of the
rearmost support flange for this floor panel.  The floor panel is held in
place by large screws which screw into steel clips attached to the
support flange.  The area around the hole where the clip is located on
the flange is heavily corroded/nonexistent.

Have been on vacation, so only read your post today.  You may have already
come up with solutions but:

You could try welding or screwing in patches to cover the missing or weak
parts of the support flange, which you could then redrill for the steel
clips.

>I want to stay away from steel fasteners
in this location which I guess is susceptible to corrosion because of
mud/moisture from the rear wheel, or the lack of grease/oil thrown in the
area (no similar extent corrosion on the front intermediate floor support
flange).

I wouldn't worry too much about using steel fasteners.  I've owned my SIII
for twenty-eight years, and I've not had any serious rust problems with the
fasteners the factory used, despite their being the cheapest grade crap
that the company could buy at the time.  It's STAINLESS steel fasteners I'd
advise you to stay away from.  Coating the steel fasteners you put in with
LPS-3 (not -1 or -2) will help ward off rust, and there are other products
you can use for this purpose, too.  I use LPS-3  once a year on the
fasteners and springs on our boat trailer, and it's been pretty much
rust-free for over 15 years despite regular dippings in salt water.

>I'd also like to hear from folks on using plastic discs under
washers in contact with aluminum, as well as plastic between the tub and
the frame mounting tabs?

Big waste of time unless you can figure out how to insulate the fastener
itself from the metal it's holding together.  As I explained in another
post, any conductive connection between two pieces of dissimilar metals
carries the potential for electrolysis and its associated corrosion.  So
you not only have to insulate the parts themselves from each other, but the
barrel, head, and threads of all the fasteners as well.

The crummy steel used in Series Land Rovers, the cheap fasteners, the tinny
washers, and the aluminum alloy skin are not all that far apart on the
Galvanic chart.  So the potential for electrolysis on the "stock"
components of a Series is not all that great.  Where you could get into
trouble is if you start using stainless steel on the vehicle, particularly
for fasteners that are going to be in conductive contact with the aluminum
alloy skin.  Your biggest problem will be rust, depending on how you use
your vehicle and the environment where you live.  Priming and painting
installed fasteners and/or coating them with LPS-3 or some other adhesive
protectant is your best defense against rust.  Makng sure there are drain
holes in the bottoms of door structures and so forth helps, too.

As I recall, you live in Oregon.  I don't believe they use salt on the
roads down there, and unless you drive a lot on the beaches, I don't think
a humid, salt-air environment is going to be a factor for you.  So giving
the new steel fasteners you install in your floor a good painting and/or
coating of LPS-3, etc. should protect your repair for many, many years.

And if you do what I do, and put off replacing a leaking front crank seal
for decades, the oil blown back under the vehicle at speed will prevent
rust from forming on ANYTHING, even if you live in a hot, humid, salty
environment out in the middle of the Pacific.

________________________
C. Marin Faure
  (original owner)
  1973 Land Rover Series III-88
  1991 Range Rover Vogue SE
   Seattle, WA