R80ST master cylinder leak

[donkeydoo]

Have had front brake reinstalled and bleed for a few weeks now and have just noticed a darn leak , was being tight at the time and did not renew the piston. It has had new reservoir and o ring and all been cleaned.

Just wanted to check with the more knowledgeable folk if there is anywhere else the leak could be from other than the piston.

Cheers

 

[scooter paul]

If it’s not coming from the hose joint then the most likely place is the piston.

 

[scarf100gs]

Just stripped mine down, found a pool of fluid in the hand guard been dripping over winter. The cylinder looked clean with a slight bit of corrosion at the top near the circlip, polished this off with fine wire wool, bought a new piston from motorworks but still a small ammount of fluid leaking. Will give it another go but for the time and cost wish I had bought a new Master cylinder.
Cost of piston kit £50, cost of new master £170 so I have probably wasted the £50+postage and lots of time/brake fluid, beer and saved nowt! The choice is yours.

 

[Kenny]

As above, these old airheads need many parts to be renewed.....often false economy with the age of these bikes to try for a quick fix. I'd bite the bullet and fit a new complete master cylinder.

 

[donkeydoo]

Cheers all for the advice.

 

[Nin]

As above, these old airheads need many parts to be renewed.....often false economy with the age of these bikes to try for a quick fix. I'd bite the bullet and fit a new complete master cylinder.

That. Then you know it will last another 50 years.


Sent from my iPhone using Tapatalk Pro

 

[Hoff]

Where do you get a new master cylinder from?
When I did mine a few months ago I could find any available.
It would be good to know!

 

[scarf100gs]

Here you go:
https://www.motorworks.co.uk/parts/brakes/master-cylinders-reservoirs.html?condition=166