Brake problem - thought I'd share this.

[Itineo]

http://forums.sohc4.net/index.php/topic,183397.msg2288457.html#new
Here's a thread I posted on a few years ago with a seeming intractable problem with the front brake on my bike. Thought it may help someone on this side of the pond.  After getting the MC and caliper refubished in 2020 the lever was soggy despite anything I did. Mechanic said he did all he could but no success.  I spent a lot of time and some money on it before finding a solution in the place I least expected. I don't know the sequence of events that led to the mismatch of thelever and MC piston, but it would have been the last thing I would have logically thought of.

[McCabe-Thiele (Ted)]

Interesting as my 400 & 500 both seemed to have a lot of movement in the brake lever before contacting the master cylinder.
As I'm not a Concourse man I fitted a new DS master cylinder - sorted with almost no free play in the system.

[Mike_Berkshire]

That’s good to know Ted as I have the same DS replacement waiting in my ‘new parts box’.

Having never worked on hydraulic brakes before I will be having my first adventure with this in the next week or so. I’m hoping I can refurbish/rebuild the old caliper with new piston and seal once I get the old piston out which I am intending to use the grease gun removal trick with.