MG Car Repair: MG TD / TF Gear Box, replacement gears, followup question

Question
I bought your gearbox dvd & it is great.  A followup question concerns the brass syncro inserts. How can you tell if they are badly worn & need replacing. Any thickness spec ? UK source ? Simple "how to" replace ?

Answer
Hi Bill.  Thank you for your comments regarding my TD/TF Gearbox DVD.  

Turning to your question - the brass synchromesh inserts have several grooves machined into them.  So long as you can clearly see these grooves they will be OK.  If they have worn smooth, you have a problem because they are worn out. I am not aware of anyone who can supply replacements, although you can still buy replacement gears with new synchro rings already fitted.

They were originally a tight fit and just peened into place.  If you look carefully you may be able to make out some diamond-shaped dents where they were locked in place using a very small punch.  Sometimes they just come loose, in which case you can re-tighten them with a centre-punch.

If anybody out there knows where I can get replacements, please let me know!