Hi all, thought I'd submit my Z3 roadster (98 2.8 55k mi) trunk floor/ diff mount fix. Did this entirely without welding. I basically bolted in two 1.25" steel angles in the trunk using .25" bolts above the diff mount beam, and also added in a custom bracket behind the diff mount to relieve the existing mount bracket, which I left in place as mine had not started cracking yet. The original tool tray still mounts in the trunk with just a little trimming.
Couple of things I noticed. On my car, the orig diff brkt was bent forward about .10" when bolted down, so I added in a .10" washer onto the 12mm bolt to relieve it of this extra stress. I also noticed that using the rear of the diff as a jacking point is not a good idea, I suggest using under the cross member just under the rear U joint. I first used the diff as a jack point when starting this project, but was dismayed as I saw the rear of the diff bend up almost an inch as I loaded it with the jack.
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Couple of things I noticed. On my car, the orig diff brkt was bent forward about .10" when bolted down, so I added in a .10" washer onto the 12mm bolt to relieve it of this extra stress. I also noticed that using the rear of the diff as a jacking point is not a good idea, I suggest using under the cross member just under the rear U joint. I first used the diff as a jack point when starting this project, but was dismayed as I saw the rear of the diff bend up almost an inch as I loaded it with the jack.
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