Bleedin' brakes

[ColinChandler]

Hello everyone,
I've just fitted a remote servo to go with the disc brake set up I've got and obviously I need to bleed the brakes. Is it best to do it with the engine running so the servo is working as it would when driving or is it as easy to do it with the engine off? I've heard the merits of both ways. Any opinions are welcome. Cheers, Colin.

[bmcecosse]

Engine ON !

[ColinChandler]

Thanks for that. Regards Colin.

[Onne]

I have never seen the people at the garage where i work, bleed the brakes with the engine on! I din't do that with the golf either! What's the big advantage over the oldfashioned (?) engine off method? I like my silence, so I can shout 'press' and 'release' at my mate! but that is IMVHO

[salty_monk]

Engine off. I've never seen anyone do it with the engine on either.
The easiest way is with an ezibleed type kit & a spare cap that's drilled to take the tube.

[Onne]

that's what I thought anyway.

[Cam]

I've never done it with the engine on either, but I would be interested to see if it makes a difference. My MG B bled fine last time when I replaced the master cylinder seals and that has a servo.

[bigginger]

I've never bled brakes or seen them bled with the engine on either - which may explain my difficulties with the process. What is the reasoning behind the dogmatic yet enigmatic "Engine ON !"?
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[paulk]

Never left engine on but have used little brother to pump the pedal and thus saved myself all the effort

Paulk

edit 'Unless the engine on is just to power the servo and thus make the pedal pressing easier? if so using younger siblings is just as good'

[Cam]

Yep, I'd agree with that Paul! My little sister has assisted a lot in the past with the pedal pressing and so has my mum, dad and nan! In fact anyone who happens to be near my garage door when I need assistance!

[jonathon]

I cannot see a valid reason for 'engine on' the servo is part of the braking system and once each cylinder is bled its properties in regard to fluid capacity does not change. We have bled hundreds of servo assisted systems in the engine off mode with no ill effects. A road test to prove the system is always carried out . I'd be interested to hear why the the engine should be running though.

[bmcecosse]

Just to make sure you get the full stroke of the servo cylinder really - personally I would throw the servo away - hateful things !!

[bigginger]

Classical Practics this month (next month... ) says something along the lines of "If you can't get a solid pedal [on a servo system] try bleeding again with the engine on" BTW. No explanation of why though...

[Cam]

Pratical Classics eh? Well, [sarcasm]It MUST be right then! [/sarcasm]

[bigginger]

Ooooh, new html tags! I think it's written by the same people as the Haynes manuals...

[bmcecosse]

Was the PRATICAL an intentional 'slip' ??

[Cam]

Would I do such a thing?? I have to say that when I find myself stuck at a motorway services, such a magazine is a great source of entertainment!

[bmcecosse]

The 'Performance Classic' mag to which half the %&^$s from Pratical Classics absconded is even worse ! One bright idea the Editor had was to braze up the cracked main bearing caps on his V8 engine !! I ask you !! The rest of the 'advice' is equally 'helpfull'.