Topic: K7 vs pre-K7 Front brake differences

[Erny]

Hi all,

does anybody know what are differences between pre-K7 and k7 hydraulic front brake?
Obviously there are some minor differences in master cylinder (even not understand what is exact difference), then I see differences in brake caliper..

Are key rubber parts compatible? Or I need to look for specific parts for K7?

[beemerbum]

Check out the youtube video Hack-a Week with Dino where he rebuilds a master cylinder having bought '77 parts rather than 69-76 rebuild kit

[seanbarney41]

The caliper uses different brake pads...the 2 styles are not inter-changeable.  K7/K8 caliper is the same as 75-76 750f

[Don R]

Seabarney is correct, The late calipers also have a bigger piston and a centered bleeder/ inlet fitting. That makes them easier to use on dual disc conversions.

[Erny]

Thanks, this is important info for me. Some ehops seems messing this up as they offer the same parts for pre-K7 and K7. I need to be careful.

[scottly]

Early calipers had a 38mm piston, while the 75-76F 77-78K had a 42.8mm (actually, it's 1 11/16 inch) piston. The late style pads have a "D" shape, which covers less of the rotor surface. All 750s except the 77-78F used a 14mm master cylinder, although there are differences in the rebuild kits. Also, the K8 MC had an integral brake light switch, instead of the hydraulic switch used on all other models.