HZJ75 vs. HZJ78/79 axle housing strenght difference?

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B

Blade

10 Year 15 Year
Joined
Jun 29, 2010
Threads
34
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252
Location
Switzerland
I searched a long time here but couldn't find if the HZJ75 at least on the rear axle has a stronger axle housing and stronger 3rd member as the newer HZJ78/79.
I met now 2 overlanders with HZJ78 that had a BROKEN rear axle and one of them has original TOYOTA reinforcements welded to the rear housing to prevent from cracking again.
Anyone has more infos to the differences, also for the front axles?

Thank you!

Cheers from Sucre, Bolivia
 
My HZJ75 has a square front axle housing and round rear housing. The HZJ78 in front of us has a square rear housing with those reinforcing plates to prevent cracking of the housing as already happened.
By the way, he has 3tons, we 3.8tons!
It's the second HZJ78 i see that cracked the complete rear end! So made me worry with my 3.8tons we carry!
 
I have been advocating for some time that the factory Land Cruiser axle housings are not strong enough, and if you run a heaving truck (i.e. over 3,000kg's) or big tires (i.e. 37"+ tires), with Leaf Springs, then a bent or broken housing is more of an inevitablity, than a possibility.

The Leaf springs prevent any ability to gusset and reinforce the axle housing from the point where the u-bolts attach outwards to the wheel. When you bottom out the suspension on a big 'whoop' in the road, the torque on that housing bending around the bump stop is more than those housings can handle.

I've bent two Land Cruiser rear axle housings in that exact manner... heaving truck, overlanding equiped, bent rear axle housing. They were an FZJ80 and BJ74 Full Floater housings... not 78/79's, but my point stands...

Nowadays, I am upgrading to 14Bolt housings on heavy and/or big-tired trucks.
 
Good infos!
I made a picture of this reinforced HZJ78 reax axle housing. To me it looks the same as the front square axle housing my and his car have.
My rear axle housing is round!? so i would guess it's stronger than his rear/front square design since i have the square one on the front where you have less weight. Or am i wrong?

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