Rear brake caliper bleed ??

[Dinger1962]

Morning foccers my rear brake was feeling a little spongey so decided to bleed it (simple enough i hear you mutter under your breath --Well here goes) one side bleeds nice and clean no probs  however the other side producing more air than Piers morgan with absolutely no sign of clearing --My thought was bleed nipple anyone come across this before an how did you resolve it --thanks for any input --20 minute job now into hour 2--

[robbo]

Had a similar problem when I changed the brake line on my thou. I took the caliper off and suspended it higher than the resevoir. If you've got access to a "hypodermic", you could try reverse bleeding, by introducing the fluid via the nipple and watching for bubbles in the resevoir. One other thought is air getting past the nipple threads. Possibly some ptfe tape wrapped around the nipple. One final suggestion, after you've bled it as best you can, leave it overnight with the pedal depressed, either with a heavy weight or by tying it down to something immovable. Good luck

[Dinger1962]

have aready trid ptfe tape to no avail and also tried back bleeding which is why am bit baffled tried bleeding while suspended as well --think ill get couple of new nips tomorrow and start again --thanks

[Fazerider]

I guess you’re trying to pump the air out. Just loosening the nipple will allow air in the cylinder to escape as it’s always under slight pressure from the reservoir. You might need to twist and turn the caliper slightly while tapping it with a screwdriver handle to help dislodge any small bubbles stuck inside.
The rear brake system is a bit of a pain to bleed because bubbles can also get caught in the master cylinder, slacken the banjo at the top to get rid of any air trapped there.

[Dinger1962]

thanks gonna go watch moto gp will try all options tomorrow after work --

[His Dudeness]

You could bleed it at the banjo bolts. Start at the master cylinder and work back. Hold pressure on the lever as you open the bolts. Then tighten them back down while still holding the lever

[Dinger1962]

Well chaps got to the bottom of the problem--it was a pinhole in the piston due to corrosion hope this helps anyone with similar problems--

[fazersharp]

Well chaps got to the bottom of the problem--it was a pinhole in the piston due to corrosion hope this helps anyone with similar problems--

So would it be acceptable to smear some ACF50 or - the - like down there during a caliper clean up and service.   

[Dinger1962]

new pistons will be getting some form of protection befor fitting and during each service from here on --

[darrsi]

Well chaps got to the bottom of the problem--it was a pinhole in the piston due to corrosion hope this helps anyone with similar problems--

So would it be acceptable to smear some ACF50 or - the - like down there during a caliper clean up and service.

Red Rubber Grease, which i mistakenly just bought a shiteload of, by accident from not knowing the weight per measure.

[Northern Biker]

https://www.wemoto.com/bikes/yamaha/fzs_600_fazer_sp/01/picture/stainless_steel_piston_and_seals_rear_caliper