Starting to look at replacing my wheels and tires on my 76. The previous owner had installed a fake dually setup. I know they're horrendously unsafe, but I love how the truck looks with the additional tires in the back. I was considering pressing in longer ARP studs, but feel like I'm polishing a dangerous turd at that point.

What are my options for making this a reliable setup? If there are none, is there any way to do a true dually setup with some sort of a cheap axle swap from another truck?

 

Those are factory spacers. There’s nothing that will replace them, and you don’t want to.

They’re known as “foolies”. To carry the extra weight of the motorhome, they added a second wheel to the existing axle. Turns out this can cause the axle shafts to break. Because it’s a semi-float axle and the axle shafts carry all the weight. When they break the wheel and tire will detach from the vehicle itself with no warning. There was a national recall on this problem around 1985.

Stay with singles, or to be safe change the entire axle. You’re light enough to run with single tires in the back.

https://toyotamotorhome.org/forums/

This is the best source of technical information on Toyota motorhomes out there. There’s an entire section dedicated to the bad axle situation.

There are also several FB groups that deal with Chinook motorhomes (that’s what you have).

 

Probably safer to run a wider wheel and a fatty of a tire than foolies

 

Same problem. The extra width extending out from the hub puts the load to the outside of the bearing. Over time this causes metal fatigue on the shafts making them subject to failure.

Keep in mind the axle shafts on this rig have been run stressed like this for 47 years. New bearings with 0 offset wheels will help. Any damage done to the axle shafts over time is still there.

In addition, if he’s running the GO82 rear axle no replacement shafts are available. They are no longer made.

 

It’s a simple leaf-spring axle, you could certainly swap to a better axle from either a newer Toyota dually, or another axle of similar (desired) dimensions, of course you would need to do some significant research and measuring. To me the setup doesn’t look unsafe at all, as stated the load is extreme on the axle shafts, but other than that I see no real issue with it.

 

The setup is UNSAFE. This is why they had a federal recall on foolie axles. The axle by itself is plenty strong. Adding the extra tire put more stress over time on the axle shafts. Many cases of people driving down the highway and their rear foolie tires and wheels separate completely from the motorhomes. Not a good image to my mind. This defect didn’t become obvious until 1985 when the recall went into effect. All subsequent Toyota models starting in 1986 had a true full float axle.
There are replacement options out there. I installed a GM 14 bolt, 10.5 ring gear ff axle on my rig. Not cheap, but plenty strong.

 

Overloading the axles is unsafe, yes, but the setup itself seems fine to me.

 

Well you’re alone in your diagnosis. All the facts I’ve presented are easily verified by an online search. Or read the article below.

https://toyotamotorhome.org/forums/applications/core/interface/file/attachment.php?id=22558

You have no personal knowledge on this subject. Why do you feel the need to jump in?

 

I remember the King of Cheezy Automotive Products, JC Whitney, used to sell "dually conversion" kits exactly like this in their catalog....

I wonder why, besides to keep costs down, the conversion company that made the Chinooks didn't just use the dually axle used under the flatbed trucks...

 

I’m not arguing with you, but if you feel that way I’ll stay out of it, lol.

 

Toyota didn’t offer a full float dually in 1976. The GO82 3/4 ton axle was the strongest one available. All the commercial cab and chassis’s sold by Toyota came with the GO82 axle and single rear wheels.
The problem was not a Toyota issue, but the manufacturers who used the cab and chassis for things like motorhomes, flatbeds and anything using a second set of wheels to increase weight carrying capacity. The dually axle you saw under the flatbed trucks in 1976 was the same axle as the motorhome. Just like the motorhome it had an extra wheel added.

At the time nobody realized the adverse effect it would have on the axle shafts.

Toyota actually commissioned the Chinook. It was sold through Toyota dealerships.

 

My apologies for being unclear. I've seen flatbed Toyotas with 8 or 10 lug nut pattern dually wheels but I don't remember what year those flat beds trucks were. I guess I just assumed all Toyota flatbeds had true dualies....

As for OP's dilemma, would bolting on a steel, 5-lug to 10-lug adapter/spacer on the hub, thick enough to bolt on a pair of real dualie wheels work? This would then put the spacer behind the pair of (real dualie) wheels instead of between a pair of standard steelies. Seems that would be a little better than the current janky setup.

And if that would work, why wouldn't/didn't the company that Toyota commissioned build them that way?

 

There were companies (or maybe still are) that made conversation kits to change semi float axles to full float. They never caught on, and were very expensive to purchase.

Regarding Toyota. Somewhere around 1983/84 Toyota produced a true ff axle for use with dual tires. This was brought on by the axle failure of the foolies. They were originally sold to manufacturers for replacement axles. Later, Toyota incorporated them into cab and chassis’s used for motorhomes and any application requiring additional weight carrying capacity.

Starting in 1986 model year all Toyota motorhomes had this new axle. It is easily identified as having 6 lugs vs 5 like the foolie. It also had a protruding hub and used wheels 6x7.25 bolt pattern.

Toyota only commissioned the Chinook which was built mid to late 70’s. Everything else was private manufacturers. Toyota had no liability from the foolies, but wanted to continue selling their cab and chassis’s.

 

This would only make the problem worse.
I’ll try to explain what happened with the foolies.
With a semi float axle the weight is transferred to the axle shafts themselves. The further away from hub the wheels project put tremendous strain on the shafts. The GO82 axle is exceedingly strong when used as intended with single wheels and zero offset. The second wheel when added transferred this weight to the outside of the bearing. This constant flex over time caused the shafts to break apart. When this happens (usually with no warning) the entire wheel assembly including drum separates from the axle. Not a good thing. There were lesser issues with things like a flat bed truck because the weight was usually transitory, not constant like with a motorhome.
Remember, Toyota only commissioned the Chinook. Technically they would be liable for any chinook damages, but not sure how that all worked out.

 

Hmmmmm.... interesting.

I always thought the rear axles wouldn't have many (any?) issues since they're so simple. Never thought about axle shafts being a problem.

Learn something everyday...

 

The replacement axles are known as full float. All the weight is carried by the housing. The only thing the axle shafts do is turn the wheels.

Most large trucks use ff axles.

I did one better. My rig is light enough to run single wheels in the back. I installed a GM 14 bolt, 10 1/2” ring gear ff axle. Same setup used on 2500&3500 trucks.
No broken axles here.

 

I didn't need all that much convincing that the foolies are unsafe. I'm not planning on keeping them. But I would really like to keep the dually setup on the truck. I have a line on a 6 lug, 2WD full floating axle out of a 1991 Toyota 1 ton truck.

Anyone know how hard of a swap that is? If it's more or less a bolt-in job I'd pull the trigger on it, but I don't want to do a ton of fabricating to make it work.

 

Spring perch’s need to be adjusted to fit your frame rails. Other than that it’s a pretty straight forward installation.

I’ve never done it myself, but that’s what’s being said on Toyota motorhomes site. You should become a member. All your questions will be answered by folks that have done the swap.

Edit: you’ll need all 4 wheels that go with that axle. Very difficult to find them individually.

 

I’d guess the 91 axle is a few inches wider too, based on how the non-dually ones grew a few inches with every generation truck. Would that have clearance issues against the motorhome body?

 

That’s the same axle Toyota provided for replacement of the foolie axle. Everyone who’s done the swap has never mentioned a fitment issue with the wheel wells. Spring perch location is the only major fabrication needed.