Z1OwnersClub GB

Have had problems with front brake caliper piston seal leaking. Replaced seal as piston seemed fine (stainless steel). Still leaked so ended up fitting new piston and another new seal, it still leaks, only a weep but enough to fail MOT, can't be the seal to piston so can only think that fluid is leaking around the back of the seal. Is it possible to use some sort of bonding/sealing agent to fix the seal into the caliper to prevent leaking around it? If so what should I use? Anyone had similar experience?

Hi john, have you ensured that the groove that the seal sits in is really clean?and are you fiiting dry or using brake fluid or red rubber grease on assembly?

clean it up then dust it with talcum powder - that should help poin point where the fluid is coming from

Fitting with v light smear of red grease, groove is really clean so can't understand it, I must be going wrong somewhere?
Is it better to fit dry (sure makes the job more difficult getting the piston in) Should I try light smear of brake fluid on the seal before assembly. The leak is very slow, drip on floor noticed after winter lay up of approx 5 months, when in use it doesn't seem to manifest itself (or maybe because I clean the bike after every ride I'm wiping any tiny traces away?)
It's bugging me

I know this doesn't help but mine does the same thing but only on the right hand side. changed seal, strip and cleaned but still leaks driving me mad as well!

IF You look at some seals they are not flat on the surface that seals onto the pistons but are slightly shamfered! try rotating seal 180 degrees! Try It, hope it works Paul J...