1977 Z1000 Rear Master Cylinder O Ring

[Speedie]

Hello all
I am looking at refurbishing the rear brake cylinder on my Z1000 A1. I found a couple of good videos (American) on you tube, one where the chap replaces the square section O-ring between the main body and the plastic reservoir. Would anyone have any links for the O-ring in the UK? I've had a search around but no luck. I know the normal piston and seals kit is available from Zpower, but obviously doesn't include the O-ring I'm after

Philippe very helpfully posted these sizes back in 2019.

When it's leaking between the plastic cup and the alloy body you can replace the O-ring. It's easy to remove the cup, only two screws hold it there. The O-ring has an external diameter of 52 mm and is square. The height is 2,85 mm, the width is 2,35 mm.
I think you can find that O-ring in the UK somewhere

One a separate note, were these original cylinders reasonably ok for actual stopping power or could I consider a more modern replacement? Am thinking something like the rear cylinder on my 93 750 zephyr, which does a great job. But then again am I expecting too much from the 1977 brake caliper itself?

Thanks
Paul

[Kev1R]

Rear brake on my A2 (& previously owned Z1R) will overwhelm the rear tyre if used over enthusiastically.
A 70's Z1000 on modern tyres and brake pads with braided brake lines and properly bled brake system is miles better than it would have been when new & I have no complaints with mine.
Hope this helps

[Speedie]

Thanks Kev, much appreciated.

That's good to know. I also feel I could lock up the back wheel on the Zephyr as well. Quite surprising when generally these days you hear how average modern rear brakes are considered.

Rear brake on my A2 (& previously owned Z1R) will overwhelm the rear tyre if used over enthusiastically.
A 70's Z1000 on modern tyres and brake pads with braided brake lines and properly bled brake system is miles better than it would have been when new & I have no complaints with mine