Posted: Thu Jan 30, 2025 9:38 am Post subject: M38 Front Axle to Frame Bumper Replacement
First time posting but have been lurking for some time. Lots of great info and appreciate the opportunity.
I recently acquired a 1951 M38 (non runner) that I have begun a full motor pool restoration on. I am in the process of disassembling the vehicle and am noting components that need to be replaced or repaired. The four axle to frame bumpers are dry rotted and will need replacing. The rear pair will be simple enough. Access to the fasteners for the front pair may be more challenging. The parts diagram seems to show the bolts being threaded into the frame. If not, and nuts are used, how is access gained to the closed frame member without a specialized wrench? I have not been able to find this referenced in the manuals.
Thnx!
Joined: Oct 02, 2014 Posts: 2040 Location: South Carolina, Dorchester County
Posted: Thu Jan 30, 2025 1:41 pm Post subject:
Hi Hovering,
Welcome to the forum!
Yes, the front axle bumper hardware can be a challenge.
The 5/16-24 bolts don't thread into the frame --- they thread into weld nuts (listed in the M38 ORD9 on page 274).
Ideally you can remove the old bolts without breaking the weld nuts loose and clean up the threads using a thread chaser.
If the weld nuts break loose there's no way to replace them without cutting into the frame to gain access for welding.
I don't know of anybody who would go to that trouble, including an Army mechanic back in the day.
My opinion is they'd simply replace it with a hex nut.
(You're correct, the repair isn't referenced in the manuals)
If I remember correctly (one of mine was busted), it's a square weld nut.
You can replace it with a regular hex nut using patience and finagling it in place using mechanical fingers or a telescoping magnet.
Once you get the bolt started on the nut it'll usually thread up tight without need for a wrench on the nut.
If not, as you suspected, you may need to "customize" a wrench to fit into the nearest access port in the frame to cinch it down.
Good luck! _________________ Ron D.
1951 M38 Unknown Serial Number
1951 M100 Dunbar Kapple 01169903 dod 5-51
“The only good sports car that America ever made was the Jeep."
--- Enzo Ferrari
A liberal soaking in PB Blaster must’ve done the trick. Was able to remove all without breaking a single bolt or busting the front weld nuts. Found 74 years of caked grime underneath the dry rotted axle bumpers. One step closer to a restoration.
Thnx for the insight.
Joined: Oct 02, 2014 Posts: 2040 Location: South Carolina, Dorchester County
Posted: Sun Feb 02, 2025 4:19 pm Post subject:
Good to hear that, and thanks for the follow-up.
Too many leave us hanging...
Have you done anything to clean out that boxed-in part of the frame?
Mine was loaded with crud including mud-dauber wasp nest.
Got most of it out with long handled stiff brushes and compressed air.
Good luck! _________________ Ron D.
1951 M38 Unknown Serial Number
1951 M100 Dunbar Kapple 01169903 dod 5-51
“The only good sports car that America ever made was the Jeep."
--- Enzo Ferrari
Thought about using the paint stripper over the entire frame followed by a generous pressure washing. Should not only rinse away leftover chemical but flush the enclosed frame sections. Hope it will be sufficient.
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