Unless you are talking about a big rig which can have air hoses to connect the brakes of trailers, most cars and light trucks have no air brake lines, the only place where usually air (vacuum) exists is between the engine in an ICE and the brake booster attached to the master brake cylinder. So technically not a brake line, though it is providing the power for the brakes. In an EV the lack of engine (intake vacuum) requires a vacuum pump and typically a reservoir, attached to the brake booster. As David indicated, one trick is to reverse the pump and create pressure (you can also use a tire pump but be careful not to put too high pressure in the lines) and use the flat tire patch trick of a bit of soapy water to allow detecting the leak by bubbles escaping. Some people have even advocated to do away with the vacuum altogether as it limits the amount of pressure and convert the brake booster to pump pressured air into the opposite side of the diaphragm so ambient pressure exists where there used to be vacuum and pressure exists where there used to be ambient air pressure, this allows a higher pressure so more force and longer working brakes with the same reservoir size, or a smaller booster.
Bending and flexing the hoses and listening to the typical hissing sound of air in a quiet environment is often the fastest way to detect leaks. However, leaks can be interior to pump, reservoir and booster as well. Success finding the culprit! Cor van de Water Chief Scientist Proxim Wireless office +1 408 383 7626 Skype: cor_van_de_water XoIP +31 87 784 1130 private: cvandewater.info http://www.proxim.com This email message (including any attachments) contains confidential and proprietary information of Proxim Wireless Corporation. If you received this message in error, please delete it and notify the sender. Any unauthorized use, disclosure, distribution, or copying of any part of this message is prohibited. -----Original Message----- From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of Sam Shepherd via EV Sent: Friday, October 28, 2016 10:41 AM To: Electric Vehicle Discussion List Subject: [EVDL] vacum leak Anyone have a tip on how to find a vac leak in the brake line? thanks -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20161028/f41b 1860/attachment.htm> _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org Read EVAngel's EV News at http://evdl.org/evln/ Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA) _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org Read EVAngel's EV News at http://evdl.org/evln/ Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
