It's an internal spring wire ring which lives in a annular groove in the splined section.

C6Dave wrote: ↑Sun Jun 30, 2024 3:24 pm When you look at the cap from below (tank side) in that hole in the middle there is a spring inside, so wonder if that is the vacuum release.

I'm pretty sure the spring acts on the floating 'ears' to set the clamping force of the cap.

Mine does the same (1991 non-cat). I used a smear of rubber-friendly grease on the sealing ring to make opening easier.

Is the thermostat the right way round in its housing?

I usually start with Rimmer Bros: https://rimmerbros.com/SubCategory--Rov ... s--m-28188

Unfortunately the usefulness of their site has declined over recent years. In your case, there don't seem to be the exploded
diagrams I usually expect to see.

The whole issue of the windscreen wipers needs further investigation, particularly WRT the problem of the securing nut / arm body hitting the bonnet edge when it is opened. Maybe you've hit the nail on the head with the inner hole wear you've noticed. My take is that, over time and under continuous...

Johnny 216GSi wrote: ↑Sat Jun 15, 2024 11:23 am They were either dipped once and left to cure, or they were sprayed once and that was it.

I'd discount dipping, as the rear surface is uncoated.

I've just looked up the OP's GSD471 - it is for a 216.

For the 214, GSD467 is shown in my list.

Reading across, but slipping a line, the following part is "NLA - Use GSD471", so maybe that's where the confusion has arisen.

There's a GSD467 on eBay's Italian site at the moment.

My eyes are tired, but YBD10062EVA looks to be for a 216 to me.

I think what the OP's friend wanted was Item 3 on here.

I think the 'worn track' Dorchester reports may be the slip rings. These are obtainable as
service parts, and are straightforward to replace if you can solder.