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Early R107 front subframes (roughly 1972–80 territory) can crack in known stress areas. Check on a lift before you trust a pretty nose.
Related: rust check, buying guide.
Where and how to check
Inspect weld/stress regions on both sides with bright light and clean metal. Surface rust is not the same as a crack — but ignore neither.
Repair and cost
Proper repair/reinforcement needs fixtures and a shop that understands these frames. Cheap plate-and-paint over a living crack is a future failure. Price repairs into the purchase — or walk.
Common mistakes
Skipping cold and hot tests, trusting verbal history without invoices, replacing parts before measuring, and ignoring rust while chasing mechanical gremlins. Photos from another market or year are not a parts catalog.
When to stop DIY
Stop when you lack the gauge, puller, or safe support the job needs — or when the first repair did not change the symptom. Pay for diagnosis with someone who sees R107s regularly.
Practical takeaway
PPI undercarriage time is not optional on early cars.
Shop notes and paperwork
Keep invoices, pressure readings, part numbers, and dated photos of the area before and after work. The next owner — or future you — will ask what was actually done. Verbal “we took care of it” evaporates at sale time.
Safety and scope
Use jack stands on solid ground, relieve fuel/coolant pressure before opening systems, and disconnect the battery when the procedure calls for it. If a step needs a specialty tool you do not own, rent it or hire it — improvising with the wrong lever is how fasteners and fingers break.
Verify against the factory manual for your engine and chassis. No invented personal car details here — use your plates, invoices, and measured symptoms.
Shop notes and paperwork
Safety and scope
If this topic intersects fuel, rust, or safety systems, fix the safety and leak paths before cosmetic or convenience items. That order saves money twice.
