Pressure testing rear brakes

[mgcjag]

Hi All.....Just rebuilding the IRS...Ideally I would like to pressure test the brakes (new pipework/pistons/seals) etc....before installing......Dont really want to install & find I have brake fluid leaking....A friend uses a dry gas to leak test air conditioning units & has offered my its use.....Any ideas of what pressure the braking system uses.....Thanks..Steve

[christopher storey]

I do not know the actual operating pressure , which of course varies with pedal pressure, but you can be sure that it is at a very minimum several 100s of pounds /sq.in and more likely several 1000 lbs/sq.in. or to put it in metric terms soething between say 40 and 400 bar . It is very difficult to reproduce these pressures with gas as opposed to liquid because it is just too compressible. However, if a cylinder is going to leak , it will do so at quite low pressures, so provided you have either a very sensitive ear ( to hear gas escaping ) or a sniffing device, it may well work

[Heuer]

Applying vacuum might be a better way of doing things. Have a look at the Mityvac range - hand operated with a gauge. Any leak will quickly reveal itself with the needle dropping. As a bonus you can use the Mityvac to bleed the brakes with consummate ease: http://tinyurl.com/3a86wxc

[mgcjag]

Thanks Guys....The gas used is dry nitrogen so you get a visual sign similar to white smoke if any leaks...the cylinder has its own pressure regulator so Ill start at a low pressure as suggested.....& see how it goes . Thanks Steve