Copper "grease" on bolts

[TedW]

And, since stainless is further away from aluminum on the galvanic series, the aluminum will tend to corrode more quickly than if a steel bolt were used.

This may be technically correct, but my real-world experience doesn't bear this out.

My truck was 21 years old when I go it in '91. It spent its life in Maine, and had all the usual aluminum corrosion: where the steering box cover rubbed against the inner wing, where the tail lights were grounded on the tub, etc etc etc. Every nut/bolt seemed to be rusted into one piece. Ugh.

I proceeded to replace all the fasteners with stainless, and in the following 20 odd-years have seen no evidence of aluminium corrosion with stainless fasteners. And this is while living within sight of the ocean - we have salt air, salt water, salt snow, salt on the roads in winter, salt everything. People's cars can rot just sitting in the driveway here.

So I guess I'm going to continue to schlep to Ace Hardware for stainless. Just my $.02.

[jac04]

True, but I've minimized the area that will be corroded.

Again, not really. Please don't take this the wrong way, but you don't fully understand galvanic corrosion. The physical electrical connection between the metals is not where you see the galvanic corrosion. It is the surfaces of the metal that are exposed to the electrolytic solution.

Anyhow, I guess I'm getting a little too technical on the subject, so I'll just drop it.

[TedW]

Anyhow, I guess I'm getting a little too technical on the subject, so I'll just drop it.

IMO this subject should be ongoing. It seems that we are all trying to do something that the elves at Solihull went after half-heartedly: stopping rust.

Yes, the body is aluminum, but that was an accident of history, and as we have discussed here, comes with its own set of problems.

Yes, some parts are galvanized (thankfully), but many more are not - like the bulkhead and the frame (which IIRC was galvy on early protos and dropped for cost reasons).

And it seems that the designers went out of their way to make a truck that has the maximum number of dirt traps and critical areas / wiring that get sandblasted from daily use.

We are all trying to keep our beloved 40+YO beasts on the road while not dissolving before our eyes. Let's keep sharing what we have learned.

[Terrys]

Galling in stainless isn't really a problem if you use a different type of stainless for the nuts and bolts. For example, use a 316 stainless nut AND bolt, and it'll probably jam up during tightening, but use a 316 stainless bolt and a 304 stainless nut and you'll be all set.

Mark, Not to put too fine a point on it, but the only difference between 304 and 316 is Moly(bdenum) and they both have the same physical properties (Yield, UTS, E2" and RA) and will gall equally.
Mongoswede, 300 series stainless is far from brittle; it's quite soft, with a much higher elongation than carbon and low alloy steels. Brittlness, a lay term for ductility, Elongation and reduction of area is measured both by pulling tensile bars, and Charpy V Notch testing. 300 series test bars pull like taffy, and when heat treated (quenched and solution annealed)for maximum corrosion resistance, and has max UTS in the 65,000 psi range, and yield strengths of around 35,ooo psi, very low compared to low alloy carbon steel, but much higher ductility. Grade 8 fasteners are made from Low Alloy carbon steels with yield strengths of 85,000 min yield, and 105,000 min UTS (Ultimate Tensile Strength) They are lower in Ductility than 300 series stainless steels, but because their strengths (Y & UTS) are so high, are not effected unless over stressed.
The above useless trivia is garnered from 30 years producing Carbon, Low Alloy and Stainless Steels, with full chemical and physical testing labs.
My major customers, GD Electric Boat, GE Power Generation, and Dresser Rand were pretty particlar about the quality of our castings. (up to 15 tons)

[albersj51]

I agree, this is a good conversation. I am very new to Rovers and have been thinking about ways to reduce the corrosive effects of differing metals, so I am learning a lot here. Thanks for all of the technical data!

J

Again, not really. Please don't take this the wrong way, but you don't fully understand galvanic corrosion. The physical electrical connection between the metals is not where you see the galvanic corrosion. It is the surfaces of the metal that are exposed to the electrolytic solution.

Anyhow, I guess I'm getting a little too technical on the subject, so I'll just drop it.

[printjunky]

I agree with both of Ted's last posts. My real world, unscientific observation, in an uncontrolled environment (for what that's worth) is that stainless through the Birmabright is not as insidious as regular steel. Though, of course I can't see down to the molecular level. Could be going all to white powder somewhere under the surface.

Ted's next post aligns with my own Rover ethic as well. Finally (after having and losing two other series III Rovers [check my other posts for that story]), I have (though am not driving yet) my dream car back in my driveway. (I also consider myself lucky that my dream car isn't a Ferrari 250 Dino - though if you're offering ...)

Since I bought my first Series Rover in about '90, I've called them the ultimate recyclables. I expect/hope I'll never buy another car (though I also have a low miles Miata if I need to get up to highway speeds quickly).

So bring on the corrosion-beating, rot-reducing, gall-ungalling, life extending (mine and the Rovers) hints, tips and tricks!

[mongoswede]

Mongoswede, 300 series stainless is far from brittle; it's quite soft, with a much higher elongation than carbon and low alloy steels. Brittlness, a lay term for ductility, Elongation and reduction of area is measured both by pulling tensile bars, and Charpy V Notch testing. 300 series test bars pull like taffy, and when heat treated (quenched and solution annealed)for maximum corrosion resistance, and has max UTS in the 65,000 psi range, and yield strengths of around 35,ooo psi, very low compared to low alloy carbon steel, but much higher ductility.

Yep, Just reviewed my material data and realized I was wrong. For some reason I had it in my head that it was brittle...not sure why. I work with A286 (660 stainless) all day...amongst other materials so i should have known better.

[109 Pretender]

Carroll Smith has a great book on fastener do's and don'ts although it's geared more for racers. A lot of good points have been brought out in this thread and anti-seize is very good for fasteners that you intend/expect to remove again - especially if those fasteners will be exposed to road grime and moisture like suspension bolts. I'd personally never recommend s/s for any stressed connections that are critical like suspension bolts. Absolutely true that reduced friction will affect torque so compensate as necessary or install as manual indicates. (If you use ARP rod bolts they will come with special lube and a much higher torque setting because they have calculated for the reduced friction imparted by the lube). Personally, I used s/s for all little screws like the window seals because they work better in that application. I also like the looks of s/s for body fasteners because they won't surface corrode and are largely exposed - but it's not original and that can be an important consideration for some folks.

Let's not forget that our vehicles usually had a hard life, were seldom washed and maybe even covered in decades worth of mud - in other words, the worst case scenerio for electrolysis to start. And yet, by and large the vehicles survived. Now that the vehicles are in the hands of caring owners I expect all our Rover's to have another 40 years or so left in them because we try to do correct repairs, keep 'em reasonably clean, and we are aware of the problematic issues of alum./steel combos. Just keeping things clean, insulating w/paint and nylon washers where possible, and vigilant watch for corrosion potential will provide more dividends than just about anything else. Remember, electrolysis requires more than dissimiliar metal contact - it requires a moisture conductor with ionic content. Dirt, mud, etc along with water provides the vehicle for the conduction process to begin.
So give the old girl a bath now and then and pay attention to the areas that collect the grime!

Cheers!

[amcordo]

Again, not really. Please don't take this the wrong way, but you don't fully understand galvanic corrosion. The physical electrical connection between the metals is not where you see the galvanic corrosion. It is the surfaces of the metal that are exposed to the electrolytic solution.

Anyhow, I guess I'm getting a little too technical on the subject, so I'll just drop it.

True about not understanding the physics and chemistry behind the corrosion - but I feel like maybe you haven't tried it much on your rover(s)... You can tell me it'll turn to dust all you want and I'll tell you this:

I'm just going off real-world experience now. As I said earlier, the nylon washers and SS hardware the PO put on ten years ago haven't caused any aluminum to turn to dust, so it is what it is. Just wanted to share my experience with everyone so that they'd have an option if they wanted to move my route towards a rust-resistant rover (YAY SS and Galvanized steel!)

[printjunky]

Quick aside on insulating washers, in recording studios, we use nylon 'shoulder washers' (washer with a bushing attached, basically) when hanging gear in racks, to ensure, or at least maximize electrical isolation, so as to eliminate the hum from various grounding issues. If it's not going to hum, it's not going to go galvanic. (Though I suppose it would while (if) the electrolyte bridges any gap between the parts.) As previously stated, I would consider this anti-galvanic overkill. But there might be some extreme Rover owners out there to whom no length is going too far. (is that the Gentle Sarcasm Smilie?)

[Terrys]

Land Rover may have figured it was a good way to save money, but it never made much sense to me why they never ran a ground wire through the chassis harness to the rear of the truck, relying instead on the body being the return leg for all the rear lights. The closest point to the lights, where the aluminum tub meets the steel frame, is the 5 tabs along the top of the rear crossmember. Ever notice how those 5 spots are always eaten up? Ever notice when you take one of the rear light bases off the truck that it's frequently corroded around the screw holes. Coincidence?
Galvanic action is greatly increased in the presence of electrical currents, so running a wire, oh, say a piece of 12ga. wire, from the point where the NEG battery cable attaches to the frame, through the chassis, same route the chassis harness takes, to the rear, and to each individual lamp base, may greatly reduce the tub corrosion. I think that might be a little easier than trying to electrically insulate every fastener (and the 2 parts the fastener is fastening).
I'm sure all of you who have been around boats have noticed the heavy green 8 ga wire that goes to every through-hull fitting, terminating at the engine. Long common practice on boats is to use sacrificial zink annodes on the rudders and prop shafts.

[printjunky]

(In the pro audio world again) Similar to 'star-grounding" a guitar amp.

[jac04]

... but I feel like maybe you haven't tried it much on your rover(s)... You can tell me it'll turn to dust all you want...

Sorry, Tony. I never said the aluminum was going to turn to dust. In response to someone pointing out that galvanic corrosion will still occurr with stainless fasteners on aluminum, you stated "Already accounted for. That's why I use nylon washers on either side of my normal washers." You seemed to be stating that you were using the nylon washers because you knew about galvanic corrosion and were actually trying to do something to stop it. I was simply pointing out a key flaw in your reasoning.

Now, all the Rovers I have restored have utilized a lot of stainless hardware with no attempt to isolate it from the aluminum. I actually drove one of the vehicles I mechanically restored (a 69 SWB) through a few Maine winters with absolutely no signs of galvanic corrosion issues. The vehicle even had very thin original paint, so the aluminum wasn't well protected. However, the vehicle had a galvanized chassis which was left bare. Because zinc is more active than aluminum, the zinc on the chassis becomes the sacrificial anode.

I know you are "rust proofing" your vehicle by galvanizing a bunch of stuff, which is great. I know you are not galvanizing the chassis. Have you thought about installing sacrificial zinc anodes on the chassis?

[PeterK]

Joining in late,

I went all out on a 109 I built several years back.
Absoloutly every steel part was galvanized.
Axles POR-15
Every fastener practical was stainless
Every connection loaded with copper grease
Tub, seatbox, floors, footwells Rhino Lined
Loads of aluminium rivet nuts, with SS machine screws
All body rivits replaced with SS machine screws and SS nylocks.

What I learned.

Any connection where a galvanized part was present, there was no corrosion whatsoever with SS.

A connection between two aluminium parts with a SS fastener started to show signs of corrosian after several years, paint blistering, white dust.

There are very few such connections but it was universal.

Envioronment is daily driven work truck in coastal Nova Scotia, LOTS of salt year round.

Now I use cheap hot dipped galvanized nuts and bolts in many locations.
SS where it seems appropriate.
Genuine aluminium rivets

Cheers

Peter Knowles

[JackIIA]

here's a neat little website that i think helps to put the different anodic/cathodic stuff in relative perspective. i leave it to the engineers to understand the details (seems like every rover owner on the site with the exception of me is either an EE or an ME - seriously. no poets out there?).

but what's kind of cool is the hierarchy of sacrificial metals relative to one another.

http://www.eaa1000.av.org/technicl/corrosion/galvanic.htm