Centre crossmember replacement (and more chassis rail repairs)

Centre crossmember replacement (and more chassis rail repairs)

After a short break waiting for deliveries of new panels, and enjoying a bit of spring sunshine, I’m back into the garage, and equiped with (hopefully) all the remaining panels I’ll need to finish the job. Next task is to replace the rotten central crossmember. As seen in previous posts, both ends of the crossmember were rusted out and had been badly patched previously, so needed to be done properly this time.

I had bought Steelcraft repair sections for the ends a while back, as I was convinced that was all it needed, but obviously things were a lot worse than I thought, and the repair sections simply wouldn’t have repaired enough (as illustrated below). So complete new crossmember it was to be!

Removing what was left of the crossmember was pretty uneventful, after half an hour with a cutting disc and spot weld drill it was history.

Beneath the main crossmember itself there is this extra section bridging the tunnel gap. I assume it adds a little extra strength and helps to keep dirt from accumulating inside the crossmember. Curiously it’s not supplied as part of a new Heritage crossmember, so I attempted to keep it intact as I removed the main section, but it was a little bit too thin and corroded to be worth saving.

So I just made up a new one and welded it in.

With all the flanges cleaned up and drilled for plug welding where necessary, I clamped the new crossmember carefully in place and started welding it in. For now it was just the two ends that could be welded, which attach to the ‘castle section’ part of the sill on either side. I’m not welding it to the floors at this point, since I’ve now decided to also replace both floorpans (because I needed more jobs to do!).

I spot welded the middle section to the replacement bridging panel I made earlier.

Both chassis rails had suffered from rust where they met the crossmember to some extent. The nearside one was not too bad, apart from some surface rust it was just this flange which overlaps onto the crossmember which needed replacing.

The offside rail was much, much worse. The picture below shows the state of the inside of the crossmember in that area, with the rotten end of the chassis rail still attached to it. It was obviously beyond saving, so I just cut the whole lot off together.

And here’s the same section from the outside, along with the new piece I had painstakingly fabricated to replace it.

Repair section welded in and all ground back flush, this should put some much-needed strength back into the structure. Next jobs will be to remove the floorpan and footwell/pedal box on this same side, so it’s important to have completed this job first.

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