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[Diamond Black Geezer]

Hmmm, anyone correct me, but I have a feeling the idea if to find some wet grass / empty car park after it's rained, wherever, and activate the ABS (ie: brake dead 'ard) - this should pump round the little bit of extra fluid / air in the system and basically 'bleed' the ABS unit. But that's just appeared as a spark form the dark recesses of my mind, I could be wrong/imagined it 

[Kevin Wood]

Presumably using the expensive pressure kit? I'm wondering whether there may be some in the Elite's ABS, as the main system has been bled well.

No, you just need to exercise the ABS ECU using a Tech 2 while bleeding normally. It's unusual for it to be required, though, especially if the system hasn't been disturbed upstream of the ABS block.

[Shackeng]

Presumably using the expensive pressure kit? I'm wondering whether there may be some in the Elite's ABS, as the main system has been bled well.

No, you just need to exercise the ABS ECU using a Tech 2 while bleeding normally. It's unusual for it to be required, though, especially if the system hasn't been disturbed upstream of the ABS block.

Thanks Kevin.

[terry paget]

Begin at the corner furthest from the driver and proceed in order toward the driver. (Right rear, left rear, right front, left front.) While the actual sequence is not critical to the bleed performance it is easy to remember the sequence as the farthest to the closest. This will also allow the system to be bled in such a way as to minimize the amount of potential cross-contamination between the new and old fluid.

From a DIY site.

I accept slight cross contamination. It's not as bad as a garage oil change, which at best drains cold oil through sump plug hole for five minutes, at worst sucks oil out through the dip stick hole.

[Andy B]

... at worst sucks oil out through the dip stick hole.

Not all cars have a sump drain plug ...... hence you HAVE to use an oil sucker outerer 

[Broomies Mate]

Not all cars have a sump drain plug ...... hence you HAVE to use an oil sucker outerer 

Sump drops will be commonplace then?

[Andy B]

Not all cars have a sump drain plug ...... hence you HAVE to use an oil sucker outerer 

Sump drops will be commonplace then?

If you like ..... but it'd be a lot easier/less messy with a Pela oil sucker outerer 

[chrisgixer]

Personally, while its good to get new fluid through the system, I've never noticed any improvement in bleeding any more than enough through to clear the heat affected fluid around the caliper, which obviously means doing so with the caliper piston FULLY retracted into the caliper.

It is not possible for the fluid to take in moisture while it's in a sealed sysyem. Certainly one thats well bled and used with no air pockets on an old car like the omega. If there was air in the system for some time, then yes bleed thoroughly. But generally, for a correctly working system, insuring the caliper piston is fully retracted and bleeding normally is ample.

Certainly no need for tech 2, unless there has been a right royal OPPS up. Although failing to keep the master cylinder topped/while bleeding the master cylinder dry so the inlet sucks air would do it.

[Diamond Black Geezer]

Personally, while its good to get new fluid through the system, I've never noticed any improvement in bleeding any more than enough through to clear the heat affected fluid around the caliper, which obviously means doing so with the caliper piston FULLY retracted into the caliper.

It is not possible for the fluid to take in moisture while it's in a sealed sysyem. Certainly one thats well bled and used with no air pockets on an old car like the omega. If there was air in the system for some time, then yes bleed thoroughly. But generally, for a correctly working system, insuring the caliper piston is fully retracted and bleeding normally is ample.

Certainly no need for tech 2, unless there has been a right royal OPPS up. Although failing to keep the master cylinder topped/while bleeding the master cylinder dry so the inlet sucks air would do it.

Good advice. Like checking the fuses or battery first, it's obvious - but we've all done it, it's so simple that you forget. Well, I say "we've all done it"... what I mean is I have! 

[Kevin Wood]

It is not possible for the fluid to take in moisture while it's in a sealed sysyem.

.. except in the reservoir which is open to the atmosphere, of course. What I tend to do when servicing any of the brakes is to first empty the reservoir with an oil extractor, refill it with fresh, drain old fluid from each caliper while retracting the cylinder, then bleed a little through each with an easy bleed on reassembly. Do this every time you replace the pads and that's all you need to do, IMHO.

[chrisgixer]

no more than the air gap in the sealed bottle that's been on the shelf since manufacture.

And if the the master cylinder is open then it's not sealed.

[aaronjb]

But how do you know they don't nitrogen purge the bottles when sealing them, Chris

[Diamond Black Geezer]

it seems like we're wandering into the realms of it not being worth changing the fluid, now...  personally I'll be changing mine, but it would be great to find a kind of litmus test or something to actually determine how much H20 is in brake fluid after eg: 5 years.

[Kevin Wood]

But how do you know they don't nitrogen purge the bottles when sealing them, Chris

Exactly. And the bottle doesn't have a vent in the top to allow air in to displace fluid as the level drops. The amount of black crud in the bottom of the reservoir on cars where this has been neglected is witness enough to the fact that the fluid in the reservoir does degrade faster than anywhere else in the system.

it seems like we're wandering into the realms of it not being worth changing the fluid, now...  personally I'll be changing mine, but it would be great to find a kind of litmus test or something to actually determine how much H20 is in brake fluid after eg: 5 years.

5years! Enough. As has been discussed, you don't necessarily need to change it as a separate operation, but, each time you replace the pads, release the old fluid from the caliper as you wind it back and bleed a little fresh through. That's all you really need to do, IMHO, and it only adds a few minutes to a pad change, especially if you have an easibleed.

[aaronjb]

Reminds me I really should do that on the M3 after I cooked the brakes at Donnington and ended up with zero stopping power