Changing brake fluid.....

[philthy]

Sorted, the old stuff is like diahorrea.



Put the cap back on the resevoir and flushed the resevoir through whilst topping it up and the bubbles eventually came out. Found some air in the rear calipers too whilst bleeding the ol stuff out.

Will need some new discs/pads soon too by the looks of things

[Shug]

fcuk - you'da been better sticking your foot out the door to stop than using that! No bloody wonder it wilted on track!

[ceejam]

After changing the brake fluid on mine atthe wekend, I was thinking about it more (as you do - 20/20 hindsight).

The fluid that is most critical to braking operformance is the stuff in the calipers directly behind the pistons. Using the old "fill the reservoir with fresh stuff and bleed out" method, the stuff behind the pistons will probably remain largely unchanged!

To really get fresh fluid where you need it most, it means calipers off the hoses and turned up side down and all ways to get the old fluid out. The capacity of the S1 system is 2L, I emptied the reservoir(using vacuum bleeder), topped up and bled through 1L, which was defintely coming thorugh as clean fluid, but who knows what stuff in the calipers is like?

Am I being pessimistic and looking too far into this, or does anyone else agree?

[philthy]

Are you sure the capacity is 2L?

[woody]

Cant see it being 2L. My system was totally empty when I filled it a few months ago, It took pretty much a litre to fill.

[philthy]

same with me, used around 800ml

[woody]

I can't see a mention of capacity in the manual either.

[philthy]

the technical manual states 1.5l for the non servo assisted cars (s1 and early s2s) and to be changed every 12 months(Dot 4)

[mac]

Why go to all that trouble - leave the cap in place, remove the pads, unscrew the bleed nipple and push the pots back in - the fluid will find the easier way out and you'll get fresh fluid all the way.

I would have though that for most of us mere mortals is the water content of the fluid not that we are actually exceeding the dry boiling point.


Mac

[philthy]

think il stick to the way i did it. Once one caliper was done, the rest were easy

[ceejam]

Why go to all that trouble - leave the cap in place, remove the pads, unscrew the bleed nipple and push the pots back in - the fluid will find the easier way out and you'll get fresh fluid all the way.

I would have though that for most of us mere mortals is the water content of the fluid not that we are actually exceeding the dry boiling point.

Mac

Yes, indeed it is the water content that is the problem, and puching the pistons back with the bleed nipple open will help, but what if the calipers are full of water rather than brake fluid? Doesn't matter what how good the rest of the fluid in the system is

As you bleed it, the fluid will come in the pipe and out the bleed nipple, without really mixing with the fluid in the "pot" behind the piston.

The few replies above kind of prove what I was hoping, that no-one else has gone to the effort of totally draining the calipers - there is NOT an inherent flaw in just bleeding fresh fluid through

[Victor Meldrew]

With the easy bleed fitted you an get a reasonable flow out the bleed nipple, the "flush" effect should move most of the fluid out of the dead areas... certainly for us mere mortals the way you did it was fine.