Never seen this before...

[koda2000]

So this afternoon I was going to pick up my 4 year old grandson at preschool. I was driving my '01 ST, which has been my daily driver for a while now. I was about 1 mile from my house, doing maybe 30 MPH when I heard a strange noise and the truck started shaking violently. at first I thought I was getting a flat, then the right rear of the truck dropped and I saw my tire (with the brake drum and axle attached) rolling across the road and into the woods. Luckily no one was coming from the other direction and there was an entrance to a development to my right and I was able to roll to a stop out of the way. Obviously the axle had broken (too bad the '01 ST doesn't come with rear disc brakes. If it did the axle couldn't have come out). After 30 mins of searching I located the tire and axle for examination. What I see is that the button on the inside end of the axle (where the "C" clip holds the axle inside the spider gear) is broken off allowing the axle to side out. I've never seen this happen before except at the drag strip. There was no warning and I'm quite gentle with my old vehicles. The heaviest thing I ever tow is my small flat-bed trailer with a round-bail of hay once a month and that's about a 2.5 mile trip at 30 MPH.

A guess I can count myself very lucky that this happened so close to home and a low speed. If it happened at highway speeds with other vehicles around (and if my grandson was in the truck) the results could have been very bad. It cost me $75 to have it towed home, but I can submit that to my insurance company.

Arrrggg! Something else to fix. Oh well, it's not like I don't have something else to drive. Anyone ever have this happen to them?

 

[CDW6212R]

Good luck there, I'm glad no one got hurt. Someone was looking over you.

I had a 9" axle break on my first car, the family car we got in 1972. I had been driving to work, 70mph not long before I got off the highway. On the offramp I felt the RR drop, and grind. I turned right gently at the bottom, where it was 1/4 mile from the Ford dealer I was working at. That was a drum car of course, and the car was down on the tire. It took a couple of hours of hunting later to get an axle, for $75. After it happened I knew why, for many years the RR bearing would go out every couple of years, ever since a trip we took to MN. The bearing went not far from where my grandparents lived, and my grandfather was a mechanic. The bearing race was very scoured and clearly not perfectly true after the repair. That's why the bearings wouldn't last all that long, and eventually it killed the axle.

So even though it's not the exact same thing, I would very carefully inspect that rear end housing, you want to know how true the bearing "race" surface is, versus the housing(the hole in the carrier where the axle goes). If that isn't really true, maybe the axle was putting extra pressure on the C-clip end. I doubt it though, just look things over there super carefully. Does that make sense, it's hard to describe?

I've read about high end shops cutting the housing tube welds loose from the center section, and placed in a jig to make them true, to reweld them. The pictures I have seen show a straight bar/pipe(a straight edge), run through the rear end housing with the carrier in place. If that bar isn't equally spaced out at the housing end, then the housing tube is not true. I doubt that is a common thing to check out, but that would be my one concern. A random bad axle is so rare that I wouldn't worry about that again. I have a new pair to install here which ran a little over $200, with bearings as a kit.

 

[koda2000]

The rear end was a used 4:10 out of a 2000 Explorer. The donor Explorer was not in an accident and looked pretty well cared for. When I got the axle I had to switch it over from disc to drum brakes, so I had the diff apart to remove the axles, switch the backing plates and replace the axle seals. The axle parts seemed to all be in very good condition. The oil was clean, the axles and gears looked like new really. There was no sign of a problem until the axle broke.

This has me a bit scared of the drum brakes now. If it had discs the caliper would have prevented the axle from coming out. I don't know what to do with this rear diff. I guess I'll take it apart soon and see what's going on inside of it. It may be easier to get another used diff, this time with disc brakes, although I'm pretty sure I'll need to change the master cylinder and maybe the proportioning valve. I'll check RockAuto's on-line parts catalog to see if the master cylinder part numbers are different. I assume they would be.

I've been driving for almost 55 years and I've have covered many 100,000's of miles and never had something this catastrophic happen before. I can't even ever recall having to call a tow truck before. It's amazing how many of my breakdowns have occurred in my driveway, or have allowed me to limp home. Still, it could have been much worse.

The Ford 9" diff doesn't use the "C" clips to retain the axle. Much better design.

 

[CDW6212R]

The disc brakes would help hold the axle in, but only a little better. Any hard turns away from the bad side would eventually have let the axle get out. My 9" axle broke right at the outer location where the bearing began. In those the bearing is pressed onto the axle, with it broken outboard of that, it fell right out.

What happened with your axle is worrisome, especially if the rear is otherwise thought to be unhurt from say an accident.

For using the disc brakes, I have read many times that it's an easy swap. I don't know what others do about the MC, if anything. I'm fairly sure the Ranger MC uses a different piston, for less brake pressure. But you care about the balance of the front to the back.

I learned of the MC difference because I'm eventually expecting to need the Ranger part, if my next custom brakes produce too much force(5.44sqin versus stock 5.05sqin).

Hopefully you can inspect that rear and it either looks flawless and you guess the axle was a lemon, or something shows clearly and you have something to work on.

 

[koda2000]

The disc brakes would help hold the axle in, but only a little better. Any hard turns away from the bad side would eventually have let the axle get out. My 9" axle broke right at the outer location where the bearing began. In those the bearing is pressed onto the axle, with it broken outboard of that, it fell right out.

What happened with your axle is worrisome, especially if the rear is otherwise thought to be unhurt from say an accident.

For using the disc brakes, I have read many times that it's an easy swap. I don't know what others do about the MC, if anything. I'm fairly sure the Ranger MC uses a different piston, for less brake pressure. But you care about the balance of the front to the back.

I learned of the MC difference because I'm eventually expecting to need the Ranger part, if my next custom brakes produce too much force(5.44sqin versus stock 5.05sqin).

Hopefully you can inspect that rear and it either looks flawless and you guess the axle was a lemon, or something shows clearly and you have something to work on.

I'm expecting the diff itself to be fine. The axle tip that broke off should be with the "C" clip still in the spider gear, against the pin. I'll find out once I feel like taking it apart. If it's toast I have a line on another one for $200 complete.

 

[jmvb]

Phil: Sorry ear that, but I'm glad that you and your grandson have come back home safe and sound.

 

[Robman]

Glad you're ok Koda. This happened to my step father on his '96 Dodge 2500 Cummins, he had work done to the rear end. Drove it home on the highway and the axle walked out when he was pulled into his very long laneway.

 

[koda2000]

Phil: Sorry ear that, but I'm glad that you and your grandson have come back home safe and sound.

Thanks Jose (and Robman)

 

[lobo411]

I have a deal with my cars: I do my best to take care of them, and they take care of me. The moment they fail to keep up their end of the bargain, they get crushed into a tie tack at the local scrapper.

 

[koda2000]

Yeah I'm a bit pissed-off at this truck. After all I've done for it in the past year, this is how it thanks me...

 

[lobo411]

Tie tack time!

 

[96eb96]

glad to hear you and your grandson are ok.
I recently had a torsion bar snap - not a fun thing. I also realize that that could happen even when not driving, so going under a car or even putting your hand on top of a tire for any reason without support is a no-no.

I'm not 100% sure disc brakes can hold a wheel at speed. I've seen wheels come off from failed bearings even with discs.

I wonder if the axle could be bent out of shape by lifting it by the differential housing?

 

[MAS Tequila]

I had a spindle break on a Chevy pick up at 65 mph on I75 southbound with a 30' camper in tow.

The only thing that kept the wheel from going into right field was the disc brake.

Now that wasn't even a minor pucker factor event until after pulling over to see what was wrong.

I could tell something was 'off' but it didn't feel catastrophic.

After seeing what it was the feeling WAS a definite OH **** moment.

Koda, it sounds like it's time to put a disc brake axle back in there.

I'm glad your luck was good.

MT

 

[koda2000]

glad to hear you and your grandson are ok.
I recently had a torsion bar snap - not a fun thing. I also realize that that could happen even when not driving, so going under a car or even putting your hand on top of a tire for any reason without support is a no-no.

I'm not 100% sure disc brakes can hold a wheel at speed. I've seen wheels come off from failed bearings even with discs.

I wonder if the axle could be bent out of shape by lifting it by the differential housing?

Ford does say to not lift from the center of the diff housing, but from the axle perch instead. I must admit if I want both wheels of the ground I do jack from the center. I've done this all my life (I've seen tire places do it too). Without one of those jigs the axle shops use IDK how you could check this. A laser maybe?

 

[jmvb]

Yeah I'm a bit pissed-off at this truck. After all I've done for it in the past year, this is how it thanks me...

I has been in the same boat... (actually, I am)

 

[koda2000]

Master Cylinders:
I just did a little research on the RockAuto on-line catalog. To my surprise it shows the same master cylinder for the '01 rear disc brake Explorer and the '01 disc/drum brake Sport Trac. I don't know about the proportioning valves though. I didn't see one listed for the regular Explorer.

I'm surprised because in the hot rod world, the disc/drum and disc/disc master cylinders are always different.

 

[CDW6212R]

The proportioning valve is often in the ABS assembly now, so the MC is only about the line pressure it makes, the piston size I guess.

 

[MAS Tequila]

I have a bar attachment on one of my floor jacks, none are high enough without it, that lifts from under the axles or leaf springs or LCAs or just about any place you want.

But not from under the diff.

But like everyone else I lifted from under the diff for years without any issues.

MT

 

[koda2000]

Update:
So I received my Dorman replacement rear axle yesterday afternoon. I comes with a new axle bearing, axle seal, new lug studs and nuts. I'd read in the customer reviews that there was an issue with the lug studs supplied, but I assumed they were too short. Turns out the studs don't even fit the stupid axle (they are so small they fall right through the holes and the nuts are the wrong type - you gotta love Dorman's QC!). So I reused my old studs and lug nuts.

Everything is back together and I'm just waiting for the RTV to cure before refilling the diff with oil. I'm really a bit concerned about this hole issue and worried it may happen again because I don't know what caused the original axle to break. I guess I'll just drive the truck locally and keep an eye on it, but as I'd driven several thousand miles on the old axle (including a 150 mile 70 MPH highway trip last fall) I just don't know that I'll ever trust it again.

 

[shucker1]

I'm really a bit concerned about this hole issue and worried it may happen again because I don't know what caused the original axle to break.

What I see is that the button on the inside end of the axle (where the "C" clip holds the axle inside the spider gear) is broken off allowing the axle to side out.

First glad to hear that you had no injuries besides a quick "WTF Moment".

A) Am I correct in saying that there should be about .002 clearance between the cross shaft in the carrier and the axle tip where it slides through the side gear to allow for thermal growth? Would not enough room would force that shaft out and make the C Clip act like a small milling tool.

B) Does anyone make a C Clip eliminator kit for these rear ends?