Tub Choices, FJ-40, Pros and Cons
by Jeff Zepp
I researched aluminum (aqualu) and fiberglass (gozzard) extensively before deciding to go with replacement panels from CCOT. We are talking about a substantial investment here, both in time and money, so I did my homework.
Contrary to popular opinion, aluminum has substantial corrosion issues due to it being a dissimilar metal from the steel the rest of the Cruiser is made of, including fasteners. Any place the aluminum touches steel must be electrically isolated or else corrosion will form due to galvanic electrolysis.
And you have to heliarc any patch panels or repairs, you can't just use a regular stick welder. Think of all the items that are bolted on to the tub, from seats, rear heater, marker lights, all the stuff on the dash, you'd be amazed at the number of items that are bolted to the tub. The isolators (shoulder washers, etc.) wear out over time. Where I live, there are a lot of old Land Rover Defenders with aluminum bodies that are rotting out from the fasteners alone. Ihey all have to be electrically isolated, and then a separate ground wire must be run for each electrical item, the tub can not be used as a ground return or else you again have dissimilar metals in electrical contact.
Fiberglass has the same separate wire ground return issues, plus once it has been tweaked is a real pain to repair. Have you ever seen a Corvette that has been in a fender bender? Slide into a tree on the trail and your nice new tub is hosed. With steel you just tweak it back out when you get home. My buddy did exactly that last weekend with his 2000 4runner, looks as good as new now.
With steel, corrosion can ONLY take place when the steel is exposed to oxygen, either from air or water. Properly sealed and protected from oxygen, steel can not oxidize. The paints and coatings available today are far more advanced than what was available when our cruisers were manufactured 20 or more years ago.
Complete tubs require less labor (on the surface) for installation, but in the long run I don't think aluminum or fiberglass are worth it. One alternative is to find a rust free tub from someone who blew his motor and needs the cash fast for something else. But they are fairly rare and only come around every once in a while.
When I'm done restoring my '76 I plan to drive my cruiser for another quarter century and quarter million miles.