New one on me

[Hartlyboy]

This experience was about a rear axle clamp on a '68 656 diesel. My brother was discing when he suddenly heard a loud bang from the left rear wheel hub. When he stopped to investigate he found the forward bolts on both axle clamps had blown off. Upon closer examination it was seen that the axle keyway was out of alignment and we figure the cast key in the lower clamp had wedged against the clamp and axle producing enough force to break the bolts.

After removing the wheel it was apparent the key cast into the lower clamp had indeed popped out of the axle key and wedged hard into the clamp. The clamps , which each had one broken bolt were eventually removed from the hub and an examination shows they should probably be replaced since that cast in square key was now rounded and it would probably slip out of the axle keyway again under load. Now, the question I ask you old timers [no slight, I'm 84] is what is the "right" clamp part to look for?

Searching parts lists and other internet sources, it looks like I'm looking for a 355440R2 IH part but... some of them seem to have the cast key and some are smooth inside with the vendor using the same number. If the rest of the clamp diameter and bolt sizes fit , do we really need the keyed lower clamp? My 560 seems to use a smooth clamp { but it has been a while since I've had the wheels off it}. Might have something to do with the spin and adjust feature on some rims but other than that, I'm not sure I'd want the axle 'welded' to the wheel with a cast key.

What's the best guess of what I should look for?

 

[Mrfred54]

If you have 38 inch wheels,according to caseIH web site you need clamp 389539R1 and bolts 375463R1

 

[560Dennis]

I don’t think welding the axle or cap is a very good option. That will change the metal grain structure of axle and cap making it weak and unusable. .

 

[560Dennis]

I see the cap key is tapered like the 560 for ease of sliding wheels along axle for wheel spacing .

 

[Hartlyboy]

I don’t think welding the axle or cap is a very good option. That will change the metal grain structure of axle and cap making it weak and unusable. .

You're right. I used a poor choice of words. I meant to lock in or fix the wheel to the axle using a key built into the clamp.

My 560 which has adjustable rims has a keyway in the axle but seems to have an actual separate key fitting into the slots in the clamp and the axle . Hopefully the key would shear if over stressed and not bust the clamp. Found a new one for the 656 using the reference from MrFred [thank you , sir] and it is about $400 just for the clamp. Found used ones far cheaper [60-100 dollar range] and will go that way.

Thanks for your responses...

 

[560Dennis]

You're right. I used a poor choice of words. I meant to lock in or fix the wheel to the axle using a key built into the clamp.

My 560 which has adjustable rims has a keyway in the axle but seems to have an actual separate key fitting into the slots in the clamp and the axle . Hopefully the key would shear if over stressed and not bust the clamp. Found a new one for the 656 using the reference from MrFred [thank you , sir] and it is about $400 just for the clamp. Found used ones far cheaper [60-100 dollar range] and will go that way.

Thanks for your responses...

Good for you , finding good a used one.
Suggest cleaning key way , free of rust ,dirt paint so it slides on some fresh grease.
You ll get it take your time .
I would not also use old bolts get grade 8 and use 4 fluted clean out tap in all the treads to ensure the accurate torque .
I don’t know what the 656 is . Look it up for best torque numbers .