Old Residue behind Driver Dashboard (renewing car bodywork)

[Bourne]

It looks like seam sealant or stonechip treatment. Possibly factory applied but it could have been done by a previous owner if they happened to have the remains of an aerosol left over from coating the sills or inside the wheelarches etc..
I cant see anything here for concern, its not going to flake off and expose the underlying metal to surface corrosion. If you'd like to improve the appearance you could smooth it by rubbing it down with some 150 grade wet and dry, then a finer grade and spray over it with black or body colour.

Chris: Thanks for this. The extra detail (sanding levels) is always useful. Saves me some trial and error at the very least, and from potential disaster!

The cream coloured section looks more concerning if it's filler that's not been smoothed.

That one is down to camera exposure thank goodness. The car paintwork was originally Harvest Gold and the original paint survives in various recesses. On camera it tends to comes out as Beige (which is also what the old MoT certificates used to record the paintwork as before a previous owner went for Racing Green).

Hi David,
My first MGB GT (1971) had a similar appearance with several areas covered with what I assumed was a sound proofing / rust prevention coating. Does yours have the same appearance in the battery wells? Mine also had both wells finished in the same way and even the underside of the battery cover lid! I'm pretty sure it's what yours has. - Possibly Zeibart rust proofing when new?

best Neal

Neal: Thanks, The battery well appearance is close, but not the same. Then again that may be down to exposure to the elements over time? I’m working away from the car until the weekend, but I’ve dug out an old photo of the battery area that shows the rustproofing there, (image below).

Going through the car’s history, I can’t find any references to underseal being added (although admittedly there are gaps in the car history). The original 1974 University Motors sales receipt lists “Full Protection” (for £45) as one of the additions requested by the first owner when he bought the car. If so, this might then be, along with the body shell and the occasional flake of Harvest Gold / Beige paint, one of the only original features left on the car!

Thanks everyone for the suggestions and feedback. I will let you know what happens when I eventually tackle it.

David

Edits: For autocorrect induced crimes against grammar and spelling