Rear axle shaft replacement

[Russell Reay]

I just discovered that the right rear axle shaft has been damaged--big chunk out of the pin groove, probably related to the fact that the hub is an early one with a ridge instead of a groove. A quick scan of the books re: rebuilding the differential suggests it is quite an involved process to be done very carefully. One quick question --can I replace the right shaft w/o complete dissassembly of the banjo, ie, can I remove and replace the shaft just by removing the right housing?

[john charlton]

No is the short answer . If it was the left axle the entire assembly can be removed from the axle with the banjo still attached to the right housing . The ring gear being on the left side wont allow it to be pulled out from the right side . This forum has multiple posts on what you do next so I wont repeat . Read the good books and good luck take your time .

John in Suffolk County England .

[katy]

The axle may not need to be replaced, lots of axles w/that type of damage have gone for many thousands of miles w/out a problem. Post a good picture of the damage.

[redmodelt]

Both type of hubs will interchange, so the type of hub used does not cause the damage. They both mount the same. The nice thing about have both the same style, only one puller is needed.

If you just want to drive in the town parade, get ice cream or go to local car show, you should be ok if just want to swap out an axle. I don't think I would recommend for going on long tours, but am sure it has been done more times then admitted!

[Russell Reay]

I didn't mean to suggest that the type of hub caused the damage, but that whatever caused the damage probably also damaged the hub, thus leading to hub replacement w/o regard to its provenance. Here is a photo of the damage. If this is not fatal, it would be good to postpone the rear end teardown until another time.

[bbrocksr]

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Originally Posted by Russell Reay

I just discovered that the right rear axle shaft has been damaged--big chunk out of the pin groove, probably related to the fact that the hub is an early one with a ridge instead of a groove. A quick scan of the books re: rebuilding the differential suggests it is quite an involved process to be done very carefully. One quick question --can I replace the right shaft w/o complete dissassembly of the banjo, ie, can I remove and replace the shaft just by removing the right housing?

It was caused by the axle nut not being tight enough to keep the hub wedged tight on the axle taper allowing the load on the axle key to damage the keyway.
When the nut is tightened properly the wedge on the taper is tight enough that there is no load on the key.
If the damage is not to bad / axle and hub not cracked or rough surfaces you could put it back together and torque it properly and it will work.

Otherwise pull both drums and the left axle housing and remove the differential carrier and axle assembly.
Bill

[Tom Endy]

It is possible to replace one or both axle shafts without removing the rear axle assembly from the car. The attached article explains how to do it. I have heard that this has been accomplished in a hotel parking lot during a Model A meet.

If it were me doing the job, I would just pull the entire rear axle assembly out of the car. The axle shafts could still be replaced with out a complete disassembly.

Tom Endy

[Jim Brierley]

The key is not the main item that holds the hub to the axle, it is the "clamping force" at the taper that locks it in, so just clean it up the best you can and tighten the bejesus out of the nut. If you take the rear apart, you then have to re-set the bearing preload and gear backlash, not a difficult job but also not for amateur's.

[Russell Reay]

FYI, the axle nut wasn't even finger tight when I removed it, and there was an axle shim in place, and the key is very sloppy in the keyway. Hoping to find a decent axle at NH swap meet on Sunday.

[Tom Endy]

Originally Posted by Russell Reay

I didn't mean to suggest that the type of hub caused the damage, but that whatever caused the damage probably also damaged the hub, thus leading to hub replacement w/o regard to its provenance. Here is a photo of the damage. If this is not fatal, it would be good to postpone the rear end teardown until another time.

I would not re-use that axle shaft. looking closely at the photo I think I see a crack starting at the far end of the key slot, on the left. This crack will work its way around the circumference of the shaft and the end of the axle will come off and so will the wheel.

Also the parking brake carrier is assembled incorrectly. The cotter pins should be inboard so they don't scrape on the brake drum.

Tom Endy

[Big hammer]

A wheel coming off wouldn't be good, you caught it just in time, listen to Tom Endy he has repaired more rear ends than he can count !

[katy]

Tighten the axle nut to 90 - 100 ft lbs.

[hardtimes]

Originally Posted by Jim Brierley

The key is not the main item that holds the hub to the axle, it is the "clamping force" at the taper that locks it in, so just clean it up the best you can and tighten the bejesus out of the nut. If you take the rear apart, you then have to re-set the bearing preload and gear backlash, not a difficult job but also not for amateur's.

Shade tree mechanic terminology : ‘bejesus’ tight = 100 ft lbs on rear axle nuts of model A differential !!!