Tektro brake bleed block size? The bleed kit for my Tekro HDC 330 hydraulic brakes did not come with a bleed block. I've seen a 15mm ring spanner mentioned as a suitable alternative, but would prefer to make/buy the correct tool. 

What size/thickness of block is needed?
This model of Tektro brake uses a Shimano M575/M505/M445 brake pad - so I ordered the Shimano bleed block for these brakes (p/n Y8FZ05000) which did the job.