(partial) bleeding brakes, major fluid loss?

A rear brake line on our '04 Cavalier broke. It lost 'a lot' of fluid.

If air got in the ABS, I understand that bleeding will require a
pressure bleeder with a scan tool. This seems likely, but I'm going to
try a manual bleed first. In doing so, if there isn't already air in
the ABS, I don't want to introduce any.

- The master cylinder should be bled first?

- For the master, the AllData service manual only talks about bench
bleeding, which they say necessitates a full ABS bleed. Back in the day
(IIRC), we would bleed the master on the car, by cracking its outlet
lines one at a time. Is there some reason this can't be done?

- More broadly, can a master bleed be done so as not to introduce air
into the ABS?

- If there is air in the ABS, even mushy brakes would make it easier to
drive to a shop. I'm thinking/hoping a manual bleed will still give me
some braking. Yes? No?

Thanks

On Saturday, October 25, 2014 11:16:16 AM UTC-4, George wrote:
> A rear brake line on our '04 Cavalier broke. It lost 'a lot' of fluid.
>
> If air got in the ABS, I understand that bleeding will require a
> pressure bleeder with a scan tool. This seems likely, but I'm going to
> try a manual bleed first. In doing so, if there isn't already air in
> the ABS, I don't want to introduce any.
>
> - The master cylinder should be bled first?
>
> - For the master, the AllData service manual only talks about bench
> bleeding, which they say necessitates a full ABS bleed. Back in the day
> (IIRC), we would bleed the master on the car, by cracking its outlet
> lines one at a time. Is there some reason this can't be done?
>
> - More broadly, can a master bleed be done so as not to introduce air
> into the ABS?
>
> - If there is air in the ABS, even mushy brakes would make it easier to
> drive to a shop. I'm thinking/hoping a manual bleed will still give me
> some braking. Yes? No?
>
> Thanks



back several years ago while bleeding an abs system we ran into a problem with the abs light coming on while bleeding and it would stay on.

After some trial & error we finally got the light to go out. while bleeding the brakes don't let the brake pedal go all of the way to the floor. From what I remember their was a point where the light would go out and that is where we would stop the brake pedal. It took a little longer to bleed but the light stayed out and the pedal felt fine.

Hope this helps.


or you can always try to gravity bleed. It takes longer though.

George wrote:
> A rear brake line on our '04 Cavalier broke. It lost 'a lot' of fluid.
>
> If air got in the ABS, I understand that bleeding will require a
> pressure bleeder with a scan tool. This seems likely, but I'm going to
> try a manual bleed first. In doing so, if there isn't already air in
> the ABS, I don't want to introduce any.
>
> - The master cylinder should be bled first?
>
> - For the master, the AllData service manual only talks about bench
> bleeding, which they say necessitates a full ABS bleed. Back in the day
> (IIRC), we would bleed the master on the car, by cracking its outlet
> lines one at a time. Is there some reason this can't be done?
>
> - More broadly, can a master bleed be done so as not to introduce air
> into the ABS?
>
> - If there is air in the ABS, even mushy brakes would make it easier to
> drive to a shop. I'm thinking/hoping a manual bleed will still give me
> some braking. Yes? No?
>
> Thanks

IF the master cylinder didn't go completely dry you shouldn't need to
bleed it. Just fill the reservoir and crack a rear bleeder. Let it
gravity bleed. That way you just keep topping the fluid.

If it did go dry then you can still do a gravity bleed and SLOWLY drive
it to a shop.


--
Steve W.