Peaklander Posted September 16, 2017 Share Posted September 16, 2017 21 hours ago, ballcock said: They look simple Although I don't understand why a vacuum system works any better than a pressure system as long as the fluid travels fast enough to carry any air with it and you don't allow any back in. The difference is that pushing liquid through spaces doesn't necessarily push all bubbles of trapped air too but sucking liquid will also suck the air from those spaces. Quote Link to comment Share on other sites More sharing options...
Cynic-al Posted September 20, 2017 Share Posted September 20, 2017 I've only ever used pressure systems, does a vacuum system make it harder to find leaks? A pressure system dribbles out but is a vacuum system more likely to suck air in than allow fluid to leak out? Quote Link to comment Share on other sites More sharing options...
HoSS Posted September 21, 2017 Share Posted September 21, 2017 18 hours ago, Cynic-al said: I've only ever used pressure systems, does a vacuum system make it harder to find leaks? A pressure system dribbles out but is a vacuum system more likely to suck air in than allow fluid to leak out? Probably, but you find the leaks soon enough when you pump the brakes. Quote Link to comment Share on other sites More sharing options...
Cynic-al Posted September 21, 2017 Share Posted September 21, 2017 True, but by then you've disconnected all the kit and put everything back together Quote Link to comment Share on other sites More sharing options...
Troll Hunter Posted September 26, 2017 Share Posted September 26, 2017 I believe that the vacuum system works better than the pressurised type because as the system is under vacuum any air bubbles will expand, aiding both separation by gravity and by the flow of fluid sweeping the bubble along. In the pressurised system air bubbles will be smaller diameter and thus less likely to be swept along by the fluid flow. Mike Quote Link to comment Share on other sites More sharing options...
landroversforever Posted September 26, 2017 Share Posted September 26, 2017 A vacuum system is going to work well because by definition you've got some level of vacuum in there IE no air. If there's no air, there's no bubbles! Quote Link to comment Share on other sites More sharing options...
daveturnbull Posted October 2, 2017 Share Posted October 2, 2017 I've recently bought a Sealey VS020 which seems to do the job, if you have a compressor. Couple of provisos tho. Before you start, take the bleed nipple out and put copper grease on the threads. Miss this out and it's rubbish. It doesn't come with an airline connector so I had to pinch one off another tool. It gets though a surprising amount of air. Quote Link to comment Share on other sites More sharing options...
Maverik Posted October 26, 2017 Share Posted October 26, 2017 I've thought about this and have a cheap vacuum system myself, couldn't get it to work as it sucked air past the bleed nipple threads. Which got me thinking further, if you have a leak anywhere then vacuum will just draw air into the system, at least with pressure it pishes out. regarding flow and moving fluid, aggressive pumping usually sorts it out for me. Quote Link to comment Share on other sites More sharing options...
qwakers Posted October 29, 2017 Share Posted October 29, 2017 for the sucking air past the bleed nipple threads issue i use ptfe tape. lasts several bleeding sessions and is very cheap and effective. Quote Link to comment Share on other sites More sharing options...
missingsid Posted October 30, 2017 Share Posted October 30, 2017 Good info here as I have a hand vacumn system read for bleeding and wondered about nipple leak (ooh err). Quote Link to comment Share on other sites More sharing options...
Maverik Posted October 31, 2017 Share Posted October 31, 2017 I got fed up of trying and faffing with nipples, so I just use one of these, the one way valve perishes a bit over time but I've used them for years and they're simple and generally do the job. https://www.amazon.co.uk/Vizibleed-One-Brake-Clutch-Bleeding/dp/B008AHUF46 Quote Link to comment Share on other sites More sharing options...
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