MK1 Petrol cap

Anyone know what the difference is between a mk1 f and the mk2 or tf petrol cap is?
The mk2 definitely doesn't sit well on a early car.
I have tried searching but haven't found any information on this. 

If one has been stripped & rebuild incorrectly, it won’t seat. I had this problem having stripped mine down. The spring clips had corroded to dust & the stainless pegs were dropping out.
I replaced the pegs with proper Allen headed screws (M5 IIRC) & made brass inserts to replace the clips, although you can buy the inserts off eBay.
M

Thanks for the reply AP.
What I don't understand is why the cap in the 1st photo fits perfectly on our TF but not on either of our MK1s 
I have seen your previous post about the inserts and I'm going to get some anodised Allen bolts to match.
If I can get it to fit properly. 

R40MGF wrote:

Thanks for the reply AP.
What I don't understand is why the cap in the 1st photo fits perfectly on our TF but not on either of our MK1s 
I have seen your previous post about the inserts and I'm going to get some anodised Allen bolts to match.
If I can get it to fit properly. 

The shape of the TF cap is different to early F. Seals on the TF cap sits higher and because of that TF cap sits proud when put it on early F. Change happened with VIN number YD522572.
From YD522573 new petrol cap is introduced for MG F and all MG TF cars.

That’s interesting, I was about to look up part numbers to verify, this saves me the bother.
Anyway, big dos & little dos, it’s a good idea to mark the bits if you are stripping one down.
Thanks for the information RL & R40’.

I wonder,
do you have a part number for the little clips?
I have a spare cap that needs one.
Thanks.

I don’t think they are available as a spare. Before I rebuilt my cap I used the cut end of a cable tie & a dob of contact adhesive; just enough to hold things in place, until a proper job could be done.
I put the reusable ones in a poly bag, I’m away at the moment but will have a look in one of my “desperation” boxes, when I’m home.
M

I had a bit of a rummage through the old spares that I have and found a MK1 cap.
Stripped it down and gave the ring a coat of paint. 
Thanks for the tip about the cable ties and glue..worked a treat 

Has anyone successfully taken the lock apart, to move the tumblers to another lock. The lock that came with my car, has the cap with the slot in missing, and it was being opened with a screwdriver.

I have stripped the lock down, and have it soaking in some citric acid, and the tumblers are slowly becoming free. I notice they all have small springs in them, which look easily lost.

I have another cap on the car, which uses a different key, but I would really like to have one key for all, without replacing all the locks.

If you have all of the original wafers then you can transfer them into the new petrol cap so that you can use your original key. 
It's been a while since I have done this but from what I recall, the petrol cap uses 2 less wafers than the rest of the locks on the car. 
 

I did it a couple of years ago following advise in this forum, most probably a How to??

There is a fuel cap modification known as the 'any key mod' that you can find reference to on here. It involves removing some of the wafers. This will still need the correct Rover size and type of key to sucessfully open the fuel cap but youve guessed it, the neighbour's Rover 45 key will now open it too.