Busted Axle

My Ford 8n rear axle torque was 450 ft.lbs., I used a 3/4 in drive breaker bar and a 6ft. Pipe to tighten up that one.
 
Fatigue will kill them all eventually. One a crack gets started, it will propagate and fail at some point. You can inspect the break and sometimes see the dark area where it had been cracked for some time and then you can see the very clean spot where it finally failed.
 
V8COOPMAN said:
DO NOT use those zerks. Play like they don't exist, as many have found all that extra grease on their brake shoes. This was such a BAD idea that Ford finally removed the zerks from the housing ends by at least 1940, which MIGHT indicate that you actually have '38 or '39 axle BELLS. You did say that the Joe Smith guys re-did your rear end for you a while back. DO NOT use those zerks! Glad you're getting it back together. DD

.
Click to expand...

So, the answer is, yes; those zerks actually are supposed to get to the wheel bearings. I did pump some grease into them with the drums off and never saw any grease appear. So no harm done. I just used my fingers to put a good coating of chassis lube on the bearings, just before I put the hubs on. I will knock off the tips of those zerks to avoid any future insertion of too much lube.

I did lap the old drum to the new axle, using valve grinding compound. It looked like a perfect fit.

I put the axle nuts on with my battery impact wrench on the high setting until it stalled. Then I put as much weight as I could (without losing my balance) on the torque wrench; probably over 100 pounds on an 18" lever. Did not budge, so I think I am okay. Got lucky on alignment of the cotter pin holes!
 
I have put 2 or 3 pumps of the grease gun into the rear axle fittings on 3 different 38 Fords. Never had a problem. Moderation is the key.
 
richard crow said:
mike the housing race if it,s worn the axle will brake again from fatige
Click to expand...

I have not heard that advice before. The roller bearings in the hub are not a particularly tight fit onto the bearing surface on the axle housing, even when new. The axle itself floats within the axle housing and carries none of the weight of the car. It simply turns the drum. Stress on the axle comes from engine acceleration and engine braking, for which I have adjusted my driving habits to avoid having to ever do this axle job again.
 
I think he was referring to the ones with a lot of wear that allow the hub to move around more that it should. This starts to change where pressure is applied in the assembly. The axle is made to absorb torque but not so much for bending loads.
 
This is not meant to push his products, but my advice is to get a new, NOS axle from Fred @ Southside Obsolete. Not much more in price than finding a good used one.
 
tubman said:
He has those? I wouldn't have guessed there were any available anywhere!
Click to expand...

Yes, sir. Don't quote me, but I think I paid around $100 an axle when I installed two NOS ones when I rebuilt my rear. Shipping is another story, but like they say, where are you going to find another?

Well worth the piece of mind to me since tearing down a rear ranks up there as one of the biggest PITA jobs to do when it's in a car.
 
I got my NOS axle from All Ford Parts in Campbell CA. They are getting scarce and the price reflected that. But it was the correct fit and delivery was prompt.

Regarding potential axle stress due hub slack from excessive wear:
With the shoe fully retracted top and bottom, my drum was tight on its bearings. For the axle to pick up any vertical load the bearing surfaces would have to wear enough for the axle shaft to ride up and rub on the inside of the axle housing where the axle passes through the housing bearing area. That is at least 1/16 inch = a lot. That would probably cause brake problems, and cause a grinding sound. I have worked on a lot of worn out early Fords and never found the rear hubs loose on their bearings. I am sure it is possible, particularly if the bearings run dry.

Which brings up another question. If parked on a sideways slope and/or going around a long turn, does any of the differential lube find its way into the rear wheel bearings? Given that Ford deleted the rear axle zerks, I suspect the answer is "yes".
 
drolston said:
Regarding potential axle stress due hub slack from excessive wear:
For the axle to pick up any vertical load the bearing surfaces would have to wear enough for the axle shaft to ride up and rub on the inside of the axle housing where the axle passes through the housing bearing area. That is at least 1/16 inch = a lot. That would probably cause brake problems, and cause a grinding sound. I have worked on a lot of worn out early Fords and never found the rear hubs loose on their bearings. I am sure it is possible, particularly if the bearings run dry.
It is entirely possible and quite common. I have sleeved at least 100 early Ford axle hoiusings and rejected twice that number for sleeving because they were worn so bad the axle had chewed up the inside. The outside bearing surface was worn over 1/8 inch.
Click to expand...
Click to expand...
 
You must log in or register to reply here.
Back
Top