Thread: Brake discs

As I mentioned in another post we purchased a 1991 RRC with Crook Brakes. So we changed the Master Cylinder, but these brakes are still crook.

So yesterday I got out the verniers & measured the Brake Discs. Our Workshop Manual, for an earlier RRC [1985?], said the rear disc should be a minimum of 12 mm. Our rears were 11 mm on the verniers, and as there is a lip on the disc so it is somewhere about 10 mm on the rear discs-- so JOY, we are about to swap & replace these rear discs.

Our Front Discs are 20 mm on the verniers, with no lip, and very little scoring apparently they were machined not that long ago. But as our Workshop Manual is for an earlier RR it does not cover us for our later Vented Discs.

This Manual does tell us that 13 mm is the minimum thickness for the front discs, presumably for the non-vented type of disc where we have the later Vented Discs on this 1991.

Could someone with a more up-to date Workshop Manual please tell me what is the minimum thickness for those Vented Discs?

Now back to the question of the rears. Will 1985 RR rear discs fit the 1991, as we do have a wreck of a 1985? If not how about a 1994 300TDI Discovery as we also have a Rolling Wreck of one of those. The 1985 Rollover would be much more convenient as it will be sent away for scap soon, while the Disco Rolling Wreck will be kept for a while as a parts car--we also have a Disco.

RRC/D1 and defender disc rotors are all the same. Apart from the vented/solid variation of course.

Going past the wear limit is a concern and needs attention, but it's not something that'll stop brakes working properly.