FJ 40 Tub Aluminm vs. Steel (1 Viewer)

[MyTwoToys]

New to the forum and in the middle of my renovation. 1972 FJ-40. My cowling hood fenders etc... are all in good shape relatively speaking and will get blasted, touched up and painted. My tub is gone. I have been leaning towards an aluminum replacement but my body lead is telling me that where the two meet up Cowling to Tub, will be a problem. I am looking for some other folks experience.

Thanks.

 

[hindsight]

I went with a PACOL complete tub/firewall...I feel it was a good choice. Here is a bit of light reading.

https://forum.ih8mud.com/40-55-series-tech/447002-springtail-mpac-1977-fj40-build.html

Doc

 

[SouthBostonFJ40]

Where do you live? Is rust going to be a future concern? If so, go with aluminum. If your body guy can't line up the tub to the cowl, then find a new one who can. If you separate the old tub cleanly from the cowl, then it shouldn't be a problem.

 

[fhawk5]

Where do you live? Is rust going to be a future concern? If so, go with aluminum. If your body guy can't line up the tub to the cowl, then find a new one who can. If you separate the old tub cleanly from the cowl, then it shouldn't be a problem.

Agreed.. I suppose if the FJ40 was all aluminum to begin with, the threads on rust would be limited to the steel items attached to the unit.

 

[jmdaniel]

Where do you live? Is rust going to be a future concern? If so, go with aluminum. If your body guy can't line up the tub to the cowl, then find a new one who can. If you separate the old tub cleanly from the cowl, then it shouldn't be a problem.

Agreed.

 

[grant5127]

Aluminum...

my body lead is telling me that where the two meet up Cowling to Tub, will be a problem..

Over the years I've installed 8 and got #9 in the making.. never had a alignment problem or any other... send it to me and i"ll put it together for ya.....

 

[Huroneymoose]

If the aluminum tub, and steel fire wall are properly isolated, no problem. Auqualu has been pumpin' out tubs for years, decades even. Todd has a superior product, and exceptional customer service.

 

[green73]

Had a similar problem on my FJ40 years ago. I went with the aluminum tub. I had to get a little creative in the toe-board area as my cowl was worse off than I thought. I isolated the steel/aluminum contact areas with aircraft grade sealants/adhesives and thin sheets of teflon. All OE bolt holes at the base of the cowl mated perfectly to the Aqualu tub as well. Another area that takes some figuring out with the Aqualu is the trans tunnel. It is square vs. the curved OE design. The bolt pattern at the firewall is the same though. Some like it, some do not. If you aren't in it for a "numbers matching" resto, you have to balance the cost/use/looks equation that works for you.

For what it's worth I have beat the crap out of my Aqualu tub and it is holding together very well. The only "issue" I have had is my own fault. I trimmed the rockers down a bit, and with sliders bolted directly to the rocker the passenger side has needed to be re-braced. ALL of the Aqualu welds and brace points however are not bent/buckled /cracked or otherwise damaged.

Good luck, and take pics of your work.

 

[MyTwoToys]

Thanks. I actually live in the Southern Maine area. I am planning on using this for an off road toy. Thanks for the feedback.

 

[fieldsken1]

If its just off road why not fiberglass

 

[MyTwoToys]

Lining up the two items is not the issue. He is telling me that the metals will oxidize and rot out very quickly especially in the Northeast. Did you isolate the aluminum from the steel or just bolt them up?

Thanks.

 

[green73]

Like stated. I used aircraft grade sealant combined with teflon sheet for all the steel/aluminum contact areas. No galvanic corrosion whatsoever, in the several years since I put the aluminum tub on. You could use a good quality rubber and some of the newer automotive sealants just the same. Keep in mind all your body mounts, roll bar mounts, etc... when isolating the steel from the aluminum. Hopefully this helps your decision.

Now you are probably also hearing how tough it is to paint aluminum too. A good self etching primer after a good scuffing of the bare aluminum should be done before painting it.

 

[Henry James the 47th]

Like stated. I used aircraft grade sealant combined with teflon sheet for all the steel/aluminum contact areas. No galvanic corrosion whatsoever, in the several years since I put the aluminum tub on. You could use a good quality rubber and some of the newer automotive sealants just the same. Keep in mind all your body mounts, roll bar mounts, etc... when isolating the steel from the aluminum. Hopefully this helps your decision.

Now you are probably also hearing how tough it is to paint aluminum too. A good self etching primer after a good scuffing of the bare aluminum should be done before painting it.

From your description I think you did all the right things in terms of taking precautions, however you are in CA and he is in ME, which are radically different environments in terms of corrosion-inducing chemicals and their use. Trying to draw conclusions from the vehicles life in CA and extending it to anywhere in the northeast is a bit dubious. I'm from the west coast myself, and I had aluminum 1/4 spacers on my rear hubs of my truck which virtually welded themselves to the hub after a couple of years here, necessitating a cold chisel divorce ceremony. They would have been fine back on the west coast for many years I'm sure.

 

[donny paradise]

. There is one common myth about aluminum body tubs: Where aluminum and steel meet, electrolysis will occur and weaken the metals. It is scientifically true that electrolysis will occur between different metals, but it's only a significant factor in marine construction where the metals are immersed in water over a long period of time. These conditions simply don't occur on a vehicle. The fact is, it's not going to happen in a motor vehicle with an aluminum body. Think about the ways aluminum and steel have been successfully used together for many years. Most aircraft, for example, combine aluminum and steel. In automobiles, the legendary Shelby AC Cobra has an aluminum body and a steel chassis. Chevrolet's new Corvette, the new Audi A8 (see AutoWeek Sept. 2, 2002 issue), the new 2003 Jaguar XJ8 sports an all aluminum body (see AutoWeek Dec. 23, 2002 issue), and even the noble Bentleys and Rolls Royces of today, (see AutoWeek April 21, 2003 for the new Aluminum Rolls Royce Phantom), and yesteryear, have been crafted of aluminum and steel in happy combination. The Ferrari Modena 360, Acura NXS, and Aston Martin Vanquish all use aluminum to enhance vehicle performance. The auto industry is becoming "bullish" on aluminunm and it's use for body parts. In summary, don't worry about electrolysis. It occurs, but so slowly and minutely that it's almost like watching the wind erode the Great Pyramids.

2. You may also hear that aluminum doesn't hold paint well. That's another myth. Properly prepped and primed, an aluminum body can be painted in the color of your choice, and the finish will wear as well as if it were painted on steel. If you're doing your own painting, consult your paint manufacturer (DuPont, PPG, Martin Senour, Sikkens, House of Kolor, etc.) for proper prep and finish-coat techniques. [For further information about steel versus aluminum, see "Aluminum: Know the Facts," printed by the Aluminum Association, 900 19th Street NW, Washington DC, 20006.

3. The last somewhat odd myth is that aluminum is not a natural grounding metal. This is WRONG. According to my 7th grade science class, aluminum is a very good ground and often used to ground many objects. We often use the aluminum body to ground accessories such as stereos, CB radios, and not to mention the vehicle's wiring harness


Quoted from a reliable source

 

[bikersmurf]

I stopped by and checked out the Aqualu factory 20 years ago, and have seen the quality of their work many times since. If I had the money I'd buy one... And replace my motor with an aluminum v8 also.

The aluminum tubs are much thicker than factory so they weigh about the same amount.

 

[kcustom73]

I went with an Aqualu tub a few years ago. Before I joined the steel cowl and the aluminum body I made sure to prime (with a proper primer for both materials) and paint both mating surfaces. Then used the supplied silicone adhesive (generously applied) before bolthing everything together. I don't see any issue with both materials being used together if they are prepared well.

 

[green73]

From your description I think you did all the right things in terms of taking precautions, however you are in CA and he is in ME, which are radically different environments in terms of corrosion-inducing chemicals and their use. Trying to draw conclusions from the vehicles life in CA and extending it to anywhere in the northeast is a bit dubious. I'm from the west coast myself, and I had aluminum 1/4 spacers on my rear hubs of my truck which virtually welded themselves to the hub after a couple of years here, necessitating a cold chisel divorce ceremony. They would have been fine back on the west coast for many years I'm sure.

True that I NOW live in the High Desert of California, which is very kind to steel. But I did not always live out here. I did this while living on the east coast in Virginia. Hampton/Norfolk area. So for a time corrosion/rust was a very real issue for me. Don't rush to judgement please. I have lived in many different environments in this great country, Mississippi, Florida, Alaska, Virginia, and now California, and well know how a permanent life for a vehicle in each effects care and life expectancy. I was speaking out of actual experience not speculation.

 

[jmdaniel]

3. The last somewhat odd myth is that aluminum is not a natural grounding metal. This is WRONG. According to my 7th grade science class, aluminum is a very good ground and often used to ground many objects. We often use the aluminum body to ground accessories such as stereos, CB radios, and not to mention the vehicle's wiring harness.

Agreed. Although fiberglass ladders are heavy, they are much preferred over their aluminum counterparts, with this being one of the reasons.

A 12 year old paint job on an Aqualu tub. I think its holding up....

 

[singletrackjunkie]

If its just off road why not fiberglass

I agree. I have a Gozzard tub and it is very well built, probably stronger than the steel tub. Check out http://www.gozzardcomposites.com/

 

[MyTwoToys]

Looks sharp. Thanks for the input. I will continue to research all options. Happy Cruising.