Anderzander Posted July 16, 2021 Share Posted July 16, 2021 Vacuum bled my brakes - and one corner just produces an endless supply of bubbles, pedal won’t come good, but there are no visible leaks. How is that happening ? I had refurbished the wheel cylinder, new bleed nipple, ran a hone through it, but I’m guessing air is getting in from either the pistons, bleed nipple, or pipe ? - so I’m going to replace the cylinder. But I don’t really understand what’s happening. Quote Link to comment Share on other sites More sharing options...
Stellaghost Posted July 16, 2021 Share Posted July 16, 2021 Were the cylinder pistons pushed right home, I've had air trapped before when they hav'nt been right in regards Stephen Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted July 16, 2021 Share Posted July 16, 2021 Bleed nipple too loose and letting air in via the threads? Quote Link to comment Share on other sites More sharing options...
reb78 Posted July 16, 2021 Share Posted July 16, 2021 51 minutes ago, Bowie69 said: Bleed nipple too loose and letting air in via the threads? I've done this too. Quote Link to comment Share on other sites More sharing options...
Anderzander Posted July 16, 2021 Author Share Posted July 16, 2021 Thing is it’s only happening on one corner and I’m doing it in a consistent manner - so if it is through the thread I’d assume it’s wear in the cylinder. Quote Link to comment Share on other sites More sharing options...
smallfry Posted July 16, 2021 Share Posted July 16, 2021 First, try some PTFE tape on the bleed nipple thread. Not too much, a couple of turns. Then try bleeding again. 1 1 Quote Link to comment Share on other sites More sharing options...
miketomcat Posted July 17, 2021 Share Posted July 17, 2021 Try bleeding using the pedal rather than vacuum. The vacuum might be pulling air past the piston seal where as pressure behind the seal will push it harder against the bore. Mike 1 Quote Link to comment Share on other sites More sharing options...
Arjan Posted July 17, 2021 Share Posted July 17, 2021 I have both a vacuum and a pressure bleeder and find for the brakes the pressure bleder much easier and effective than the vacuum one. For clutch the vacuum one seemt to be better - apart from not having a good fitting cap for the TWR reservoir...... Manually bleeding the system may help you to achieve a good pedal. Quote Link to comment Share on other sites More sharing options...
paime Posted July 17, 2021 Share Posted July 17, 2021 I used one of those cheap £5 one way valves when I recently did mine and it was fantastic. Just had to keep the reservoir topped up and the rest was easy. Worth a shot as you're not introducing any artificial pressure or vacuum into the system. Quote Link to comment Share on other sites More sharing options...
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