Sticking HS33 Lever

[Luke Dunstan]

Evening all. 
 

bought a brand new hs33 and did a water bleed, not used the bike since and it’s been sat inside for a few months. 
 

 Now when I squeeze the lever it sticks pretty much every time until you squeeze it a little again. 
 

is there a simple solution to to sort it, or will it need a full bleed with the proper oil? 
 

apologies if this has already been discussed a million times but I couldn’t find the answer when searching.

any help appreciated.

[Damon_Watson]

Yes mate, stretch the spring, oil the piston, gt85 the inner cylinder

[La Bourde]

It seems the piston expands when in contact with water for a long period. The info is from Adam from Tarty if I recall correclty.
There is not much to do I think.
 

[Alex Dark]

The pistons are hygroscopic, the nylon absorbs water. If you remove the seals, you can sand the of the piston down so it’s again smaller than the bore of the cylinder. If you get it to size with 120, then move up to about 600 it should work fine. 
 

You can test the fit in the bore whilst you’re doing it, it should drop to the bottom with little to no play in the bore. 

[AdamR28]

The piston will also "dry out" if you leave it somewhere warm, but of course will take water back in again over time. I think it swells to 106% size, from memory, so the long term fix is either a lathe or as Alex says above 👌