I've been watching this thread to see what was found. I'm glad it looks like a poor accident repair that has let water in in various places.
There's no evidence of any accident damage. No bent pans, no bent bits int he engine bay, no wonky panels. Just the water.
The damage underneath has been caused by the sliding bars on hydraulic lifts. The sill damage on the passenger side is a result of flying sticks and stones.
At the moment it's still letting water in a little - I obviously didn't get my finger of sealant far enough round into the corner that the edge of the door hides (poking my finger around there now that it's dry proves that). I'm waiting for a warm, dry day to put that right. I'll be bloody annoyed if it proves to be getting in somewhere else as well though...
From what I can work out, without physically removing the wing bolts, the water is meant to drain through there from the windscreen/pillar, past the door hinges. It's puddled and corroded enough to let water through into the sill whenever there is a continuous stream for a prolonged period. It then flows along inside the sill and comes out into the rear floorpan.
if you remove the rear seat and get a look at the metal underneath you often see small rust patches. pull the carpet up and check further forward and the rust patches continue. go to scrapyards and check out 156/147's that have had the carpet removed, even a 5 year old clean example will usually have rust patches splattered all over the floor pan.
I've got those, right enough. Mostly on welds. I'm going to treat them all before the carpets finally go back in.
There's probably more under the rubbery sealant/soundproof/'anti-rust' stuff that is on the inside of the pans too, but there's not much I can do about that
Anyhoo, one less problem to solve.
@HairyBlokeDude - nice trike. Don't suppose you ever took any of those things to Stormin' the Castle at Witton?