BJ42 bent front axle housing? Please check my logic. (1 Viewer)

[beejay42]

This is an Australian 1982 BJ42 with stock front discs. I have had it 10 years.
I had a front left (passenger side) disc wear badly on the back from a sticking caliper and not catching it in time, and an overdue knuckle rebuild, so launched into a full front end rebuild. New discs both sides, both caliper rebuild, both knuckle rebuild.
The short right (driver) side axle slid out as expected once the flats where lined up.
The long left (passenger) side axle was stuck fast. It took a hell of a lot of work to get it out, prying the CV from the top king pin bearing hole and pulling, to the point where the CV join separated. I managed to get the rest out with some more prying and once it finally cam out the splines on the diff-side of the axle were damaged/worn/mangled.

I assumed that this 'wear' was the cause of the binding, and I had the worry that the corresponding female splines in the diff would also be damaged/worn. A knuckle rebuild was long overdue as the left side had obvious oil/grease mixing spewing the combination on the back of the left front wheel.
anyway...
I ordered a new long left side axle and CV.
Tried to install today- it had to get (dead blow) hammered in, and bound up immediately.
I assumed the diff female axle splines where also knackered and took out the diff, as I had a good used one waiting on the shelf.
When the used diff came out both side female axle splines looked fine and the same as each other, and the new axle slid in and out of the old and the newer diff equally well.
I wasn't going to put the old diff back on, so I put the newer diff on.
Slid the new axle into the newer diff and it bound up again.
Tried to remove it and the (new) CV separated again.
At this point, and after a lot more thought, I could see that the axle was pushing very hard up against the internal knuckle oil soil, so much so that it had damaged/bent the oil seal towards the front of the vehicle and left a visible 3-4mm gap between the axle and the rear side of the oil seal (where oil will freely flow).

At this point I went through the possibilities and did the logic and assumed that as the machined mating surface between the diff and the axle housing was true and bolted up firm, and as the right short side axle was perfectly centred and non-binding, and that two diffs and two axles had produced exactly the same results, that the only thing I could thing to explain this was that the axle housing itself on the left side was bent to the rear of the vehicle which made the axle press into the forward side of the internal oil seal, and that this was the cause of the binding (and probably the oil/grease leak on this side).

I removed the left axle again, which this time required me to loosen the diff completely off. I needed to back the diff off about 12mm before the left hand axle and CV would slide in and out of the knuckle without binding as it should.

Does my logic stand up?
I don't believe I could have bent the axle housing myself- I haven't had an accident and I haven't 4-wheeled it in any situations where this could have happened.
I suspect that if the axle housing being bent is the cause of this, that It came to me like this when I bought it.

Although I have had this truck for 10 years, all I have done previously to the front end to this depth is change wheel bearings and that didn't require the removal of the axle, so I may have missed the fact that the axle wasn't sliding in and out freely like it should have.

At this point I am putting the front end back together as I desperately need to get it back on the road as it is my work truck, is full of tools and towing a trailer and I need to finish a job just around the corner.
I do want to fix this though.
I will of course see how it feels once it is back together, but I figure that if 10 years (at least) of use like this only resulted in some worn axle splines and some puked oil/grease mix, then it should at least be safe to temporarily drive it until I can figure out what is going on and replace required parts.


Obviously, going out and buying and replacing an appropriate axle housing is a tonne of work, and I can't seem to figure out any easy way to measure the 'straightness' of this axle housing, other than using the diff and axle geometry themselves....

Thanks for any advice.
I have a few photos I could try to upload but I don't think they will tell much more than my words can,
Cheers,

 

[65swb45]

It sounds like you have done a very thorough investigation and come up with the most likely problem. The good news is that you don’t need axleshafts to drive the truck, so you could and probably should put it back together without them while you’re hunting up a new housing.

 

[beejay42]

Thanks for the reply 65swb45.
I hadn't thought of leaving the axleshafts out. I've already put most of the troublesome left side back together and was planning on putting the right side together today. If it feels suspicious then I will go back in and pull the shafts out. That of course means pulling the diff back off a bit to get the left side axle to release....

Would anyone else be able to check the logic for my diagnosis- sorry for long post I had to lay the detail out.
Thanks again,

 

[nogo]

I have a BJ housing stripped down at the moment, I'll try to take some measurements.

 

[nogo]

Did your front-end show any evidence of tire wear caused by toe-in or negative camber?

 

[beejay42]

Hi nogo, I've just bought new tyres but didn't notice any evidence of negative camber wear or toe in wear on the old ones- technically as the axle housing seems to be bent bent back it would cause 'toe-out' would it not? Could the toe-in-out adjustment have made up for it enough to hide it?
I did ponder trying to take measurements and determine straightness, but it all seems a bit hard. I feel that using two different axles and to different diffs and that the diff flange surfaces mate up true, with the axle being so far out of line at the knuckle can mean only one thing...


This morning I rang around and all the local/Melbourne wreckers don't have anything to suit.

I then called around a few diff places that were recommended to me to see about getting mine 'adjusted'/repaired
One place said he would do it with a big press, the other said he would do it with heat. 3rd guy, a 4x4 specialist, said he actually had an axle housing in stock (still on a car being wrecked) and I could have it for $250, which seems fair enough and is probably cheaper than repair costs. His labour rates for swapping it over also seem fair, and would be required for a repair anyway, so I am just going to book it in and hand it over in a couple of weeks once I knock off the job I have to finish.

I don't even have a flat place to work on this car at my house, let alone somewhere undercover, so doing this front end rebuild and diff swap with the car up on blocks on my steep driveway seriously sucked- I don't dare try to do a full axle housing swap, it is just not worth my time or suffering and I have no one to help me muscle the heavy stuff around.

I also got it all back together today and took it for a test drive, new rotors, new pads, new king pin bearings, knuckles rebuilt, calipers rebuilt... Only put a little oil in the diff so it hopefully doesn't flood the knuckle with the squashed oil seal. Feels just fine. I will try to completely avoid using 4wd until I get the axle housing swapped as I left both shafts in.

Thanks for the advice.