Which Shaft is Broken

[drolston]

While cruising peacefully at 40 mph on a level stretch of road, Henry (my '41 coupe) failed to respond to a slight throttle movement. Engine would rev and clutch felt normal, but no go. Fortunately I was on a road with wide shoulders. No go in any gear, and the speedometer registered, so something broke back past the speedo gear.

Been there before, but it was always when doing some hot rod thing. This happened while just cruising. There was no clank or bang. I could hear a little rattle noise from the rear end. After getting home on a roll-back I popped the hubcaps and idled the engine in low gear. The shafts are locked tight to the hubs, so it is not a sheared key. Listened to both hubs with a bar to my ear and the rattle sound seems the same on both sides. Methinks drive shaft.

How do I tell for sure whether it is the drive shaft or an axle. Maybe pull the fill plug and see if the ring gear is turning with the engine in gear at idle?

Also, the rear end is original '41; will the axle be 16 or 18 tooth, and where might I find one? Same question for drive shaft. Can either be safely repaired by welding?

[gajeepguy]

It's probably an axle key. In my hot rodding days I kept them in the glovebox at all times....-RG

[JM 35 Sedan]

I'm thinking if the speedo is registering steady and varies with engine speed as you depress the accelerator, then something has failed behind the point where the speedo drive gear is located on the splined end of driveshaft. I'm thinking the driveshaft to pinion coupling, an axle shaft, or an axle key has failed. If it's not an axle key that sheared, then most likely that rear will need to come out.

[V8COOPMAN]

Originally Posted by drolston

After getting home on a roll-back I popped the hubcaps and idled the engine in low gear. The shafts are locked tight to the hubs, so it is not a sheared key.

Not Brokie!


DD

[Mart]

I had the same thing and it was an axle shaft.
Jack the rear end up and see if either of the rear wheels will pull outwards.

[ford38v8]

Sponsored Links (Register now to hide all advertisements)

It would be my opinion that it is a broken axle. To answer your questions about repair or replacement, an axle cannot be welded satisfactorily, but they are readily available and fairly easy to replace. Identification of the exact axle in your housing can only be made by counting the teeth, 16 or 18, can be replaced by either in compatible tooth count, or by the replacement of both axles together with spider gear in a set of the different tooth count. Compatible axle sets for your housing range from 1935 to 1941, the axle shafts themselves being 32.85" in length.

[alanwoodieman]

repaired on drive shaft that had stripped the splines in the coupler

[Brian]

yes, when the splines finally let go, there is no noise, if you break an axle or driveshaft, you invariably hear the snap!
And yes, I have stripped the splines, it does and can happen!

[JM 35 Sedan]

Originally Posted by drolston

While cruising peacefully at 40 mph on a level stretch of road, Henry (my '41 coupe) failed to respond to a slight throttle movement. Engine would rev and clutch felt normal, but no go. Fortunately I was on a road with wide shoulders. No go in any gear, and the speedometer registered, so something broke back past the speedo gear.

Been there before, but it was always when doing some hot rod thing. This happened while just cruising. There was no clank or bang. I could hear a little rattle noise from the rear end. After getting home on a roll-back I popped the hubcaps and idled the engine in low gear. The shafts are locked tight to the hubs, so it is not a sheared key. Listened to both hubs with a bar to my ear and the rattle sound seems the same on both sides. Methinks drive shaft.

How do I tell for sure whether it is the drive shaft or an axle. Maybe pull the fill plug and see if the ring gear is turning with the engine in gear at idle?

Also, the rear end is original '41; will the axle be 16 or 18 tooth, and where might I find one? Same question for drive shaft. Can either be safely repaired by welding?

After thinking about this a bit longer, before pulling the complete rear, the first thing I would suggest doing is pull those hub/drum assemblies and double check to make sure your problem is not a sheared axle key, and then if an axle is broken, you should be able to pull the broken end out of the axle housing. If by chance the problem is not a sheared key or a broken axle, then pulling the complete rear and torque tube for disassembly is in order.

[V8COOPMAN]

Originally Posted by JM 35 Sedan

After thinking about this a bit longer, before pulling the complete rear, the first thing I would suggest doing is pull those hub/drum assemblies and make sure your problem is not a sheared axle key, and then if an axle is broken, you should be able to pull the broken end out of the axle housing. If by chance the problem is not a sheared key or a broken axle, then pulling the complete rear and torque tube for disassembly is in order.

"After getting home on a roll-back I popped the hubcaps and idled the engine in low gear. The shafts are locked tight to the hubs, so it is not a sheared key."

He stated pretty clearly in his first post that it's NOT a sheared key! DD
.

[tubman]

Although it would be nice to know precisely where the problem is, it's all moot, since the rear end will have to come out and apart in any case.

[jimTN]

You do not have to pull the rear end to replace a axle, just the ring gear side housing.

[ford38v8]

Originally Posted by jimTN

You do not have to pull the rear end to replace a axle, just the ring gear side housing.

Winner, Winner, Chicken Dinner!

[tubman]

To each his own. I personally do not enjoy doing this job while lying under the car.

[Ford Freak]

Originally Posted by tubman

To each his own. I personally do not enjoy doing this job while lying under the car.

X2. I don't enjoy it either!

[Mart]

To be exact only the left hand housing needs to be removed. I did this job when I broke a shaft on my 41 pickup. I covered it in some videos.
Part 1: https://youtu.be/t0AfzS5OLYE
Part 2: https://youtu.be/i26ZSqwFIF0
Part 3: https://youtu.be/8ToEl7O01P0
Part 4: https://youtu.be/MOVxQP0aZhg

Mart.

[JM 35 Sedan]

Of course you do not need to remove the rear on an early Ford with a closed driveshaft to replace a broken axle, BUT you never know what else that failure could have damaged internally unless you pull the rear and completely dismantle it, and check everything.
Also, if the rear is original and never been apart, it's likely the seals, gaskets, bearings, etc., may need replacing.

[deuce_roadster]

My bet is an axle broken and you got lucky in that the hub/wheel couldn't move outward due to the brake shoes. When you idled the engine in gear was the Ebrake on? It would take a lot of abuse to strip the splines out of the coupling but it is over 80 years old. I have never heard of a main drive gear shearing off so does the speedo still work like suggested above? If the clutch disk came apart I would think it would be noisy but maybe not. Interested to see what this is.

[RalphM]

Agreed, it is really easy to remove the entire assy, and less painful to do it out from under the car!

[Bill OH]

If you are going to disassemble the differential to replace an axle or perhaps the coupling, I think I would strongly consider replacing the bearings, seals and gaskets, especially if the differential is original, and be done with it. And it might be a good time to use 3.54 gears. And those gears will mean changing the turtle??!!!
Sorry to learn of the problem!!!

[JM 35 Sedan]

Delete duplicate post

[ford38v8]

Originally Posted by Bill OH

If you are going to disassemble the differential to replace an axle or perhaps the coupling, I think I would strongly consider replacing the bearings, seals and gaskets, especially if the differential is original, and be done with it. And it might be a good time to use 3.54 gears. And those gears will mean changing the turtle??!!!
Sorry to learn of the problem!!!

Bill, you're talking about the difference between a three beer repair job and a complete third member rebuild.
On a side note, a tall gear ratio is not on everyone's to-do list.

[JM 35 Sedan]

Originally Posted by Bill OH

If you are going to disassemble the differential to replace an axle or perhaps the coupling, I think I would strongly consider replacing the bearings, seals and gaskets, especially if the differential is original, and be done with it. And it might be a good time to use 3.54 gears. And those gears will mean changing the turtle??!!!
Sorry to learn of the problem!!!

I'm betting he already has 3.78 rear gears in that '41, but agree that 3.54 would be better for highway cruising. Also, if changing to 3.54, I'd suggest running with 15 tooth input, 29 tooth cluster in transmission so 1st gear is not so bogged down on take off.

I absolutely love 3.54 rear and 15/29 transmission gears in my 35 fordor.

[Bill OH]

Ford38v8: My job would probably take 24 - 12oz beers - job last longer and more satisfaction????

[alanwoodieman]

let us know the outcome of the investigation, should be a case of good beer to make it interesting, how about it?

[drolston]

Sponsored Links (Register now to hide all advertisements)

Thanks for all the feedback.
Progress Report: It is an axle, not a drive shaft. Pulled the fill plug to see if the ring gear is turning, and yes it is. I did not have to go under with a flashlight to peek into the fill hole. When I got to the rear end, lubricant was pouring onto the garage floor from the ring gear picking it up the back side of the banjo. I hope I never have to do that test again, but if I do, I will use reverse instead of low gear. Doesn't much matter which axle, since they are both the same, but I will be pulling wheels and hubs later this week. That should tell the tale.

The job will be done with the rear end under the car. First, I do not have room in the garage for the rear end. Second, I have replaced several axles that way in the distant past with good success. Mart's videos were an enormous help in refreshing my memory on the details. Thanks Mart! Third, the rear end was completely rebuilt three years ago when Joe Smith Early V8 replaced the ring and pinion with 3.25 gears (which with 284 engine are great on the highway and no problem in town). So, no need for further refurbishment.

The strain and lifting is way over my limit either in or out of the car. I will enlist the services of a stout young lad to do the wrench bending, under my supervision.

So, does a stock, early model year '41 have the 18 tooth axle, or the 16 tooth?
No luck in finding either, so far. Any suggestions on sources?

[Bill OH]

Well, your limited to three beers!!! 3.25 gears and 286 ci is a nice combination. Best Wishes on the repair.

[V8COOPMAN]

.

We've had good luck getting axles and axle housing from the Early Ford Store in San Dimas, Ca. There's no telling whether Fred Wilner at Southside Obsolete (barnfind08) may have any NOS or good used. Send him a PM. Of course, remember that everybody is at Hershey this week.
DD

[ford38v8]

The tooth count changed from 18 to 16 for the 1939 model year. All else remained the same, so you may find either in your car, as they were interchangeable together with matching spider gear. When you determine which tooth count you have, you can replace that one axle only, or if you find a set of the other tooth count, you must change both axles as well as the matching spider gear.
As you have already replaced several axles in the past, perhaps your method of installation should be reviewed, as an incorrect method will surely put your axle at risk of breaking:


Examine the keyway of the replacement axle at the inner end of that slot, and reject any axle that shows even the smallest of cracks at that location.


With a flat file, remove any burrs that you see or feel on the axle taper.


Using grinding compound on the taper, install the drum loosely, and turn by hand to seat the taper to the drum. Remove and thouroughly clean all grinding compound.


Final assembly is dry, do not use any oil or grease of any sort. Tighten the axle nut to 200 ft lbs., which is comparable to using a breaker bar with a cheater, and standing on the cheater. It needs to be as tight as possible. Cotter key in the hole and you're done.

[ford38v8]

Originally Posted by Bill OH

Well, your limited to three beers!!! 3.25 gears and 286 ci is a nice combination. Best Wishes on the repair.

Bill, he's got a helper, so he'll need a sixpack.

[tubman]

If his helper is anything like mine, better get a couple of cases.

[drolston]

Originally Posted by ford38v8

The tooth count changed from 18 to 16 for the 1939 model year. All else remained the same, so you may find either in your car, as they were interchangeable together with matching spider gear. When you determine which tooth count you have, you can replace that one axle only, or if you find a set of the other tooth count, you must change both axles as well as the matching spider gear.
As you have already replaced several axles in the past, perhaps your method of installation should be reviewed, as an incorrect method will surely put your axle at risk of breaking:


Examine the keyway of the replacement axle at the inner end of that slot, and reject any axle that shows even the smallest of cracks at that location.


With a flat file, remove any burrs that you see or feel on the axle taper.


Using grinding compound on the taper, install the drum loosely, and turn by hand to seat the taper to the drum. Remove and thouroughly clean all grinding compound.


Final assembly is dry, do not use any oil or grease of any sort. Tighten the axle nut to 200 ft lbs., which is comparable to using a breaker bar with a cheater, and standing on the cheater. It needs to be as tight as possible. Cotter key in the hole and you're done.

Good info. Thanks.

[34fivewindow]

Originally Posted by drolston

Thanks for all the feedback.
Progress Report: It is an axle, not a drive shaft. Pulled the fill plug to see if the ring gear is turning, and yes it is. I did not have to go under with a flashlight to peek into the fill hole. When I got to the rear end, lubricant was pouring onto the garage floor from the ring gear picking it up the back side of the banjo. I hope I never have to do that test again, but if I do, I will use reverse instead of low gear. Doesn't much matter which axle, since they are both the same, but I will be pulling wheels and hubs later this week. That should tell the tale.

The job will be done with the rear end under the car. First, I do not have room in the garage for the rear end. Second, I have replaced several axles that way in the distant past with good success. Mart's videos were an enormous help in refreshing my memory on the details. Thanks Mart! Third, the rear end was completely rebuilt three years ago when Joe Smith Early V8 replaced the ring and pinion with 3.25 gears (which with 284 engine are great on the highway and no problem in town). So, no need for further refurbishment.

The strain and lifting is way over my limit either in or out of the car. I will enlist the services of a stout young lad to do the wrench bending, under my supervision.

So, does a stock, early model year '41 have the 18 tooth axle, or the 16 tooth?
No luck in finding either, so far. Any suggestions on sources?

Try All Ford, in California. they have NOS ford axles, i just installed two from them in a 40 rear end that belongs to a buddy.

[1952henry]

Originally Posted by V8COOPMAN

.

We've had good luck getting axles and axle housing from the Early Ford Store in San Dimas, Ca. There's no telling whether Fred Wilner at Southside Obsolete (barnfind08) may have any NOS or good used. Send him a PM. Of course, remember that everybody is at Hershey this week.
DD

I met Fred (BARNFIND08) at the Krinke auction a couple weeks ago. A stand up honest guy in my estimation.
Some bargains on parts, but not on cars or signs.

[V8COOPMAN]

Originally Posted by 34fivewindow

Try All Ford, in California. they have NOS ford axles, i just installed two from them in a 40 rear end that belongs to a buddy.

Yup, I'd say that they have a few axles to choose from. These guys are:

All Ford Parts
1600 Dell Ave, Suite A
Campbell , CA , 95008

Give us a Call
Toll-Free 800-532-1932
Local & Cell: 408-378-1935

[ford38v8]

Originally Posted by drolston

Good info. Thanks.

One detail I forgot to mention while inspecting the replacement axle: The keyway should be sharp, no roll-overs on the edges. The key itself should always be a new key of the proper length and end taper. This is a detail that under correct conditions, should never be required to drive the drum, just a redundant safety measure. The fact that most axle failures do occur at the keyway shows that in those cases, the drums had not been installed correctly.

[JM 35 Sedan]

Originally Posted by drolston

Thanks for all the feedback.
Progress Report: It is an axle, not a drive shaft. Pulled the fill plug to see if the ring gear is turning, and yes it is. I did not have to go under with a flashlight to peek into the fill hole. When I got to the rear end, lubricant was pouring onto the garage floor from the ring gear picking it up the back side of the banjo. I hope I never have to do that test again, but if I do, I will use reverse instead of low gear. Doesn't much matter which axle, since they are both the same, but I will be pulling wheels and hubs later this week. That should tell the tale.

The job will be done with the rear end under the car. First, I do not have room in the garage for the rear end. Second, I have replaced several axles that way in the distant past with good success. Mart's videos were an enormous help in refreshing my memory on the details. Thanks Mart! Third, the rear end was completely rebuilt three years ago when Joe Smith Early V8 replaced the ring and pinion with 3.25 gears (which with 284 engine are great on the highway and no problem in town). So, no need for further refurbishment.

The strain and lifting is way over my limit either in or out of the car. I will enlist the services of a stout young lad to do the wrench bending, under my supervision.

So, does a stock, early model year '41 have the 18 tooth axle, or the 16 tooth?
No luck in finding either, so far. Any suggestions on sources?

Drolston, any updates??

[drolston]

Axle is on the way from All Ford. Expensive, but good to work with.
Looking for a local mechanic to do the rolling-around-on-the-floor part.
More after the job gets under way.

[JM 35 Sedan]

Originally Posted by drolston

Axle is on the way from All Ford. Expensive, but good to work with.
Looking for a local mechanic to do the rolling-around-on-the-floor part.
More after the job gets under way.

Thank you, I think many of us here would benefit from seeing detailed pictures of exactly what failed, as well as knowing what actually caused this failure.

[danliveshere]

I stripped a 35 Ute rear axle last year and was surprised to see a very old welded axle. It had lasted a long time but I obviously didn’t reuse it again!

[1952henry]

There once was a blacksmith/welder/machinist in neighboring town from where I grew up who welded axle shafts. Course that was before the interweb experts said it couldn't be done. He welded a lot of Coop tractor shafts.