Master Cylinder

[florence]

This is very annoying and has never happened before. The master cylinder is leaking, I can't work out from where.  On a ride today I lost braking on the front.

Are these serviceable, i.e. using new rubbers, presuming they might be available?

I see there are replacement master cylinders available from Dave Silver.  Has anyone tried one?

All advice welcome.

SK

[Green1]

They are serviceable but hardly worth the effort as the kit costs as much as the new repro one from silvers.

Mick 

[florence]

is the repro one any good?

I am worried it might look a bit too shiny on my bike.  The original one has faded to a lovely gun metal grey.

oh dear, looking into this a bit more, the bit that's leaking the most is the seal from the lid of the reservoir and as my MS is at an angle it leaks from the top.  Does anyone know if the new sort seals at the top?, (unusual question I know)  Also, is it possible to buy the lid seal, I can't see any on the internet, all the kits just seem to have the piston seal.

[Trigger]

I would say, it would be better to service the one you have. The Chinese ones DSS are selling, let me say are £29 for a reason. The ones he was selling last year were a lot better than the stock he has now.

[florence]

thanks Trigger, I think you are right.  just seen, diaphragm genuine, £4 can't be bad! and repair kit £32.

Has anyone done it, is it a difficult job?

[Green1]

Iv not heard anything bad about them.I rebuilt mine because they were original
There not to hard to rebuild just a bit fiddly and lots of cursing involved when you do them for the first time.
As long as it goes back spotlessly clean it will work a treat.
I boiled mine on the hob with a dishwasher tab then gave it a half hearted polish it's now a satin silver. 

Now I know there Chinese I would steer clear.

Mick 

[florence]

Thanks Mick, I'll try it.  I don't think there is anywhere in my house that could be described as spotless, but I'll do my best.  Farmyard mechanics usually work OK for me.  I imagine the tricky bit will be getting the old piston out?

[Green1]

The worst bit is getting the circlip out I find a small pick works well just don't scratch the bore.

There's nowhere spotless in my house since owning an old bike.

Mick

[LesterPiglet]

Nothing wrong with the Silvers repro, just not as pretty a finish.

[florence]

after close inspection it seems the diaphragm has been trapped and is slightly deformed.  As a downside of having mad handlebars the fluid has leaked out at full right lock leaving it slightly too low and allowed air into the system.  Hopefully a new diaphragm will solve the problem.  I've never had this trouble before so I can only assume this is the problem.

(drum brakes would be so much better 

[Bryanj]

Drums are OK as long as you don't need to stop