How do you bleed an ABS system and is it needed?

[byez]

True or false? Pushing caliper pistons in without opening bleed valve will damage abs sytems.

Is bleeding the abs really needed or is a 4 corner brake bleed all that is needed?

 

[double vanos]

I have a friend that did indeed mess up his ABS by flushing the trash from the caliper up into the ABS unit. The Chevy dealer acknowledged that the trash had gotten washed up into some valves and small passage ways and ruined the unit. Replacing the ABS unit fixed the problem - I'm talking about a late model Chevy PU.

Mike Miller of Roundel tech advice column and BMW notable expert does indeed recommend pushing in the caliper piston with the bleed screws open - purge that old burned up fluid out! He also feels that bleeding the ABS unit is a waste of time; according to him most BMW dealers do a straight brake flush W/O cycling the ABS unit. BMW techs have the means at hand to cycle the unit but mostly that is done only when replacing an ABS unit (for whatever reason).

Personally, I do my brake flushes and then do several hard stops to cycle the ABS and call it a day.

Have yet to replace an ABS unit. Cheers!

 

[Audi Junkie]

^^^yup^^^

 

[byez]

So unlike the "turkey baster method" the abs fluid does eventually mix with the rest of the fluid?

 

[artificialist]

It does, if the ABS brakes are activated.

 

[mechtech2]

Crud or clean will mix eventually.