34 replies to this topic

[AustinCooper1967]

Am interested to know if anyone is using/has used the gravity method to bleed mini brake systems.

 

I'm due too bleed 1981 mini HL dual line system soon.

 

1. appreciate will take longer then other methods but how long roughly should I allow to bleed a full system.

 

2. any tips or advice using this method would be appreciated

 

by the way I only came across the existence of this gravity bleeding after having a chat (while round a customers house) with a mobile mechnic who uses this method.

 

 

 

[samsfern]

Ive never believed in this method, and have always done it the traditional way, with someone pumping the pedal.

[sonikk4]

Gravity bleeding?? normally you will need to pump the brakes to expel any air bubbles from the system. This in turn will need two people to carry out. The other method is to use an easi bleed which will only require one person.

 

These are the two most common methods which seem to work well. I would be interested to see how a Gravity bleed would work successfully.

[tiger99]

Gravity bleeding can not and will not ever work unless the slope of all the pipework is downhill from end to end, so the air bubbles will rise to the high end. That is not the case on most cars.

[Fizpop]

I invested in a Gunson EZbleed, a pressurised bottle fed by the spare. I can honestly say it's a revelation - £20 well spent and I've done mine about 3 times with it now.

[Gr4h4m]

I love my ezibleed system

[AustinCooper1967]

thanks forr the replies. I'm going to be one man operation so the eezibleed seems the way ahead. 

 

what psi is recomended from the spare tyre when using eezibleed on the mini brake system 

 

thanks

[Gulfclubby]

You don't necessarily need a helper to bleed. A crowbar, board or similar to depress the pedal and lock it in place against the seat will work too.

[Captain Mainwaring]

^^^ I wonder why the Halfords one man bleeding kit containing these items never took off?

[Barman]

Thirded for EZ Bleed....

[maccers]

Once I left a few bleed nipples open while I was trying to bleed my whole system after replacing all pipes and hardware (servo, master cyl, calipers, rear units, ie all new), I think I got fed up and decided to leave it, hours later I noticed fluid dripping out so naturally closed the bleed nipples. As if by magic the whole system was perfect! Someone mentioned to me this is a "venturi" method I the word was? I wanted to ensure just by leaving them open it was safe to use, the pedal felt very good though. Still dont know to this day what actually happened, if it was a series of actions or just by the leaving the nipples open.

[tiger99]

AustinCooper1967, the Eezibleed comes with clear instructions, which tell you the mnaximum safe pressure. If you exceed it, the usual thing that happens is that the cap flies off the master cylinder, spraying fluid everywhere. Not only is it a paint stripper, as you will already know, but it is toxic and very dangerous to the eyes, so you really do not want that happening.

I had one come off once, within the rated pressure, because there are two very similar but not identical sizes of master cylinder cap in existence, so please take care.

From memory, but do check your instructions, I think the pressure is 20 psi.

Edit: With plastic reservoir master cylinders, such as most dual-circuit types, it may be worth securing the reservoir to the bidy with a tywrap or two, in case it tries to pop out of the two grommets that it sits in. Some designs of master cylinder have the reservoir adequately retained by a pin, but others just have the rubbers, which are not intended to deal with internal pressure.

Edited by tiger99, 05 June 2013 - 12:08 PM.

[SA MINI]

or try bleeding the brakes the other way round lol

Take a look at this video on YouTube:

[midridge2]

gravity bleeding is a method for getting rid of stubbon air in the system when bleeding does not work.
i have tried this a few year back when my mini would not get a good brake pedal after the whole system was renewed.
the car was facing down hill and the back end on axle stands, i connected a long pipe onto the n/s/r nipple and taped it up onto the rear screen and opened the nipple and left it over night.           brake was no better the next day.        i disconnected the pipe and left the car for a few weeks (with the nipple closed) and when i tried the pedal the brake pedal was fine,  i can only assume that it was still trapped air and letting it stand it came out from the master cylinder.

[Captain Mainwaring]

or try bleeding the brakes the other way round lol

Take a look at this video on YouTube:

 

And wreck the seals on the master cylinder on quite a number of cars.

 

Try it on a honda CRV, and because of the way the master cylinder lays - you'll blow the little pocket of crud that gathers at the blind end of the cylinder and wreck all the seals.

 

Old Wyatt Earp there didn't mention that if ya keep blowing that dawgawn firewater in and don't get off ya horse and take some out the master cylinder, then it'll piss all over the place when it over fills.