2011Arms forum
Cracks discovered in IIIa arm sections during restoration and bearing replacement
15 years old. Gear and prices may have changed since.
What the thread found
- Cracks were found throughout the long sections of aged IIIa arms, particularly concentrated around areas where axles and bearings are located.
- A specialist suggested welding cracks as a viable repair method, though cosmetic results may be unsatisfactory.
- Machining replacement arm sections from scratch is a viable alternative to welding, though costly at approximately 1100 EUR for four sections without bearings.
- Having machined replacement sections created an opportunity to obtain technical drawings that could be reused for future repairs.
- The issue appears to be associated with the age of IIIa and Luna arm designs.
Depends on
- The observation comes from a single arm inspection during restoration work.
- No definitive cause for the cracking was established in the discussion.
- Welding feasibility and long-term reliability of welded repairs remained unconfirmed.
- The cost and time required (two months machining) may not be practical for all users.
- The discussion does not clarify whether the cracking is a widespread problem or isolated to specific units.