Brakemotive

iTrader: (73)

The ABS system uses valves controlled by your cars computer to modulate pressure. When you run the lines dry air gets trapped in the system and in order to fill it with fluid, the valves need to be cycled. A TECHII device can cycle them during the bleeding process, but the tool is usually only available to GM Tech's or service centers.

An alternative is to hotwire the ABS motor, or you can bleed the brakes, activate the abs (wet black top) and repeat until a firm pedal is achieved.

The bedding in procedure is critical to getting the maximum life out of your rotors. The process delivers an even layer of friction material and heat tempers the brake rotor. "Warped" brake rotors are typically caused by an initial uneven pad deposition which creates minute high spots on the rotor surface. Those high spots get hotter than the surrounding areas and eventually the extreme heat converts the iron to cementite, a much denser compound. As the surrounding softer (by comparison) iron wears, the high spots become exacerbated. The end result is brake judder, or warped rotors.

Bottom line is any time new rotors/pads are installed a controlled break-in procedure should be considered mandatory, not optional.

As far as the OP's brake fluid, DOT 3/4 & 5.1 are technically interchangeable. The DOT rating on ether based fluids simply refers the minimum dry and wet boiling point of the fluid. Dot 4 & 5.1 typically contain a high amount of borate esters which raises the boiling point. But if you use a DOT 4 you'll have to flush more frequently as the wet boiling point drops much quicker than a wet DOT 3 fluid.

For a street application, a high quality DOT 3 fluid is the best choice IMO.

PS Don't confuse DOT 5 & 5.1, DOT 5 is a silicone based fluid that IS NOT compatible with any other number!

SteelCityYaga

(Sorry for the thread hijack)

So say I install braided brake hoses, since they are downstream of the ABS valves, I can use the motive power bleeder to fill the new lines with fluid and then flush and fill the entire new system without cycling the ABS since the ABS valves never received any air?

Or is my logic "off" here?

EchoMirage

iTrader: (3)

you dont have to bleed the ABS just for new lines. its a good idea to do it once in a while, but its not mandatory every time you bleed a caliper.

mook99ta

iTrader: (3)

Yes but can you use motive power bleeder to flush the system or does the ABS need to activated inorder to push fluid through the system?

EchoMirage

iTrader: (3)

you can flush the system without the ABS active. thats how you get fluid at the caliper during normal bleeding. all the motive does is pressurize the master so you get flow at the bleeder. the same is done with pumping the brakes manually.