Just keep in mind that we have hydroboost assist so any pedal travel tests need to be done with the engine running.... When the engine starts it charges the accumulator cylinder on the hydroboost which hold enough pressure for at minimum 1 good stop but should get 2 more but not quite as good. The hydroboost has an effect on pedal feel.

In the GM eSI system the first step for both manual and pressure brake system bleeding is "With the ignition OFF and the brakes cool, apply the brakes 3-5 times, or until the brake pedal effort increases significantly, in order to deplete the brake booster power reserve." which is the hydroboost accumulator. Attached is a doc from the GM system on excessive pedal travel. Pretty much it also states that a "spongy" pedal feel is almost always air still trapped in the brake system somewhere and to do a pressure bleed. Also attached is a doc on the ABS bleed from the GM system.

 

Would anyone feel like measuring the distance from the steering wheel their pedal goes with engine on, off and driving? Just curious....maybe I am just used to my Volvo and Kia.

 

Here you go.
Meaurement taken from centre of brake pedal to lowest point on steering wheel, nearest to driver.

Engine Off, In Park, No Press default distance = 26.5"
Engine Off, In Park, Max Press dist = 30.5" (4")
Engine Run, In Park, Max Press dist = 32.5" (6")
Engine Run, In Drive, Max Press dist = 30.5" (4")
Engine Run, In Drive, Press dist to stop car creeping forward = 27.75" (1.25")
Engine Run, In Drive, Press Dist to stop moving car "dead" = 28.25" (1.75")

Someone's going to tell my brakes are bad, but the feel good and its just passed the UK vehicle brake test.

 

Thank you so much Oceanbrave. It's pouring here right now, but as soon as the rain stops a bit, I will check these out. Whenyou say "Diet to stop moving car dead", can you still push pedal further you wanted to?

 

Yes, as per "Engine Run, In Drive, Max Press dist = 30.5" (4")"

When driving and applying brakes the pedal seems firm enough but this could be just the "feedback" from the braking system, if that makes sense.

 

Also another important point.... if the engine is running and you press the pedal hard enough you should hear the hydroboost and powersteering pump start making noise, never hold it like that (pressing very hard) for more than about 5 seconds or you risk blowing seals in the hydroboost.

 

I lose 2" on steering wheel uppermost/lowest tilt position?
Measure from the firewall floorboard or just step on the brake pedal and compare with accelerator pedal, it should go down past the accelerator pedal a bit. This is so that in case your foot slips off the brake pedal it won’t smash down on the gas pedal on accident.

 

Good point. Normal brake pedal stopping pressure should be around 20lbs. Slamming/Jamming/Jumping on your brake pedal, causes issues.

 

6" travel is excessive. Btw, what is the distance from the bottom of your brake pedal to the floorboard/firewall in normal position, ruling out carpet/floor mats?

 

just tried measuring, but its tricky.

The carpet is very "squishy" (not worth pulling up), the pedal is not flat and it's not parallel to the floor, so its hard to take datum points.....