I am just about to start refurbishing the front brakes on my series 2 project car (calipers and mounting brackets). When I put them next to an old pair of xr3i calipers and brackets they look pretty similar in size and shape. I was wondering if there was a way of telling the difference between them.

 

Don't know but maybe the piston inside different diameter?

 

Stripped the rs turbo calipers down today so will strip the xr3i ones tomorrow and compare them properly. Thought they had to be different sizes with the rs turbo having different sized discs

 

The way to tell is by the shape of the cut out on the front of the caliper.

If it is a wide triangle shape its xr3i
narrow triangle is erst
parallel is cosworth 4x4

Then the way the brake line fits, or the back of the piston section.

 

Top info Jano.