Trussed Toyota Rear Axle

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After bending my toyota axle in an accident, I had chronic, reoccuring wheel bearing issues.  It was time to build a new rearend, and while I was at it, it was time to beef things up a bit.

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A new rear axle housing was found and stripped of every mounting bracket and tab on it.  Once cleaned and checked for alignment to assure it was starting out straight, the first order of business was raising the fill plug higher to clear the new back brace.  I cut out the fill plug and welded in a piece to fill it..  I then ground the welds smooth so no one would ever know, cut a new hole higher up and welded in the old fill plug.  I also wanted to get rid of the drain plug as they have a nasty habit of pulling out when getting caught on a rock.  I was able to cut the weld around the plug and knock it out, then weld in a circle of steel where the plug was.  I went and plated over the whole bottom with some 3/16″ just for more protection.  In retrospect, I should have just shaved the bottom.

I put the axle on two jack stands sitting on a large solid steel beam.  Chains wrapped around the beam and the housing would help to pull the ends down.  A bottle jack in the middle would force the housing up and help it retain its straight shape during welding.  I have found this technique works well, but you have to be careful, too much pressure and you’ll warp the housing the wrong way, too little and its not enough to overcome the forces when welding.

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Some leftover 2x4x0.120 wall tubing was cut to fit for the back brace.  I cut templates to fit around the odd diff profiles in the housing and transferred that to the tubing.  Of course I still had to do quite a bit of grinding to get things to fit just right.  This process was repeated for the upper truss as well.

I had to cut some holes in the back brace to allow for u-bolts to run through.  I wasn’t going to be satisfied with just cutting holes in it however.  I sleeved the holes with some 1″ square tube to keep dirt and mud out.  I am not a fan of all the dimple died excess holes used in a lot designs.  Even in sunny California I feel those extra “lightening” holes tend to allow things to get filled up with mud, dirt and dust, and that creates extra weight and more importantly retains moisture which leads to corrosion.  I try to keep my designs away from retaining mud and dirt as much as possible.

The back brace was welded on first.  I took my time welding small 2″ long sections randomly.  Afterwards I released the pressure from the jack and checked it for straightness again.  There was some minor warping the I wound up fixing by heating and cooling.  The housing was rotated, reset and the upper truss welded on in a similar fashion.

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I had purchased a used Toyota e-locker and that got rebuilt with all new gears and 4.88 ring and pinion.  I had to modify the housing to fit the new diff by cutting a notch into the side, adding some material where the diff bolts up, and drilling for four new studs.

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After all the welding and grinding was done, the housing was thoroughly cleaned inside and out, then painted.  The diff was installed and the axles with backing plates reinstalled.  I wound up reusing my old backing plates and brakes as they were still in good condition, however new wheel bearings were used.

The axle has been on several wheeling trips and typical gets driven to the trails.  I have yet to have any issue with wheel bearings and the selectable locker is awesome on and off the street!

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