Bleeding rear brake, no can do!

[Decoke Dave]

         Recently fitted a new rear tyre to my old faithful Gen1, now the rear brake pedal goes right down after getting on the bike and riding it, even after bleeding the brake.   Question is have I turned over the seals in my rear master cylinder by forcing the disc between the pads and possibly forcing the piston back as can happen with other braking systems?   If so can I strip the cylinder and simply correct the seals or do I need a new set?  Or any suggestions?     I have bled many bike brakes before but never had this issue.  Many Thanks!

[Gnasher]

Highly unlikely, I've certainly never seen 'seals turned over' as you call it.  Most likely there an issue with the pads, not being seated correctly since the wheel was removed to fit a new tyre.  Assuming there was no problems with the rear brake before the wheel was removed?

Check you've got a pad each side of the disc and that they're parallel to the disc each side.  With the above checked and confirmed check the fluid level in the master cylinder, it should be between the upper/lower marks. 

[unfazed]

Like Gnasher< I have never heard of anyone turning the seals in any fazer. I have seen it in in cars, particularly Vauxhalls.

Something is sticking, and most likely the piston/s is/are returning but pads are not which means next time you apply the brake it will go down to the end.

Corroded Slide pins is a common reason. Pull the caliper and remove the pins and pads and clean them up. Clean the caliper. Check the pistons are clean.
Apply a little red rubber grease to the pistons and light coat of ceramic high temperature grease to the backs of the pads and pins and re assemble

 

[Decoke Dave]

  As there are two Vauxhalls in my family I heard about this issue from other owners, other makes as well, but been lucky enough not to be caught out!  Good to hear that it is basically unheard of on a Fazer.  I will have another go at it.  Many Thanks

[PieEater]

Don't forget there are two bleed nipples on the rear caliper and you'll need to bleed through both if you think air has gotten into the system.

[Decoke Dave]

NOW SORTED!   Bent disc!!!!!! After trying to get the bead broken on my rear tyre, nightmare!  I decided to take it to a tyre dealer to have it removed. After gouging the alloy wheel they said they would repair and paint it, leave the tyre off I said and l would fit it myself for obvious reasons!  It returned with the now bent!!!! Disc removed after repair and paint, a very average job at best! Fitted the tyre and disc then the brake issue appeared! Turns out I could not remove the original tyre due to some detrimental injected shit like a tyre weld puncture repair type stuff which caused a combination of corrosion to the wheel inner, a white hard powdery stuff and black really sticky tar type stuff! P.S. It was not a motorcycle tyre dealer that did this! YOU HAVE BEEN WARNED!  P.s. This place was run and staffed by morons!

[Gaz66]

Surprising how many morons are employed to fit tyres, most of em have no knowledge of bike tyres & rims & discs & how easy they're damaged.
Hardest bit is breaking the bead without a bead breaker, 2 G-clamps & 2 pieces of wood never fail.


I've probly fitted thousands of tyres in the last 40yrs working in dealerships, many of em being bike tyres, I've stopped no end of muppets fuckin a discs or mounting a rim on tyre machine incorrectly.
Boils my piss how someone can't do such a simple task.
Hence made a rod for my own back & became the designated bike tyre specialist   


I won't ever let anyone remove or fit or balance my bike tyres, my OCD inner chimp won't let me.