'Back in the day' . . . in the late 70's while rebuilding my S2, I discovered one trailing arm had its forward mounting boss cut down, presumably so as to get it closer to the chassis.
Long story short, after much measuring, geometry and gymnastics, I wasn't able to attain any semblance of correct rear alignment / toe-in. Upon checking the trailing arm, it turned out to have been manufactured incorrectly. That is to say, the angle formed by the bolted tabs that locate the upright was wrong.
With some trepidation, I resolved to cut 'n' shut the outer tab so as to increase the toe angle. If that went wrong, the worst that could happen would be finding another trailing arm in pre-internet days in the antipodes.
It turned out that the 1/8" thickness of the cutting disk was about right! . . or quite a fair chunk, depending on how you look at it. I welded it up and was then able to establish the correct toe setting.
My take-aways are:
1. This must have come from the factory like that - the arm was otherwise undamaged.
2. The PO must never have attained even remotely correct rear toe-in.
3. I didn't drive the car much prior to the rebuild and had put down the squirrely rear end to 'they all do that, sir' or the discovery that someone had used a section of galvanised water pipe as a rear axle bearing spacer . . and we all know where that leads.
4. Lotus saw fit to provide a drawing of the trailing arm in the workshop manual, so kudos to Colin for that.
On a more related note to the thread subject, I've toyed with the idea of inserting two M8 Rivnuts into the centreline of the chassis underneath.
Using removable stand-offs, this should permit attaching ally or steel hollow sections across the car as a basis to establish and maintain repeatable suspension geometry. I reckon it'd be quicker to bolt that on instead of doing the usual classical ballet with jack stands and string.
