As many know the problem with pre 80's 40 frames cracking due to excessive flexing ( cold rivets) and lack of proper support on the cantilever spring mount.
This Arizona rig is cancer free and freshly sand blasted making it much easier to repair the crack and improve the spring mount design.
The crack was only on the inside lower flange of the boxed section. No crack noted to the main frame, however both drivers and passenger side were cracked.
The cracks where interrupted by the factory rivet notch.
It's clear from this angle the OEM low profile gusset does little in supporting the cantilever design. My 82 (5 years newer) has a OEM gusset that carries to the top of the frame.
Using some cardboard, two templates were made to translate the pattern onto 1/4" material . Im providing the measurements for anyone interested.
The iron worker notcher made quick work of the profile features.
Five photo limit...
This Arizona rig is cancer free and freshly sand blasted making it much easier to repair the crack and improve the spring mount design.
The crack was only on the inside lower flange of the boxed section. No crack noted to the main frame, however both drivers and passenger side were cracked.
The cracks where interrupted by the factory rivet notch.
It's clear from this angle the OEM low profile gusset does little in supporting the cantilever design. My 82 (5 years newer) has a OEM gusset that carries to the top of the frame.
Using some cardboard, two templates were made to translate the pattern onto 1/4" material . Im providing the measurements for anyone interested.
The iron worker notcher made quick work of the profile features.
Five photo limit...
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