Upgrading 5G 2.0 Brakes

89 UKDM BA4 4WS (resto job!) · Post by **wurlycorner** » Tue Mar 14, 2017 9:10 am

It's a pain that imgr doesn't do links to individual pics

Anyway, if the disc only goes on as far as in the first couple of pictures there, then the chamfer on the back isn't the problem and isn't going to make a difference. That's the bore size not matching up.
Annoyingly, although mtec list the bore size for the 4g rear disc (64mm) they don't list that dimension for the 5g 2.0 disc, so I can't say for sure whether or not they are meant to be the same.

Are you sure it's not just a bit of dirt/corrosion build up on the hub that's stopping the disc going on? I seem to recall having a similar problem on the rear of my 4g's when I changed the discs. Try a bit of Emery cloth to clean up around the centre boss of the hub and see if that sorts it.

Alternatively you could take them to a local Engineering company and ask them to turn the bore slightly larger (and the chamber on the rear, if needed)?

Jackson Bondy · Post by **Jackson Bondy** » Tue Mar 14, 2017 11:21 am

I know it's a right pain!
Hmm, I did consider that but it didn't look that way to me. I'll try giving the hubs a good clean and seeing if I can get the discs on again. I'll also measure the hub and chamber to see if it's stopping the disc going and let you know.