Is my Hydroboost working?

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Sometimes it feels like my Escalade is not going to stop in time. I am on pedal hard, she still rolls to a slow stop. Pedal stays at the top, doesn't sink or fade. New pads, new rotors all around. Fluid exchanged and bled a few times. There is an occasional slight whine from the PS pump, but nothing out of ordinary. All the PS fluid was replaced when the steering gear leak was fixed this summer. No change. PS seems normal. I tried the pre startup brake test, the pedal pops up when I turn on the key.

What are the symptoms of Hydroboost fail?

Would a bad hydroboost unit only effect the brakes?
 
When the one in my GMC went out, it required standing on the brakes with both feet to get it to stop, and power steering also lost assist when you stood on the brakes. A reman PS pump & hydroboost, with Red Line PS fluid, took care of it, the old PS fluid was BLACK!
 
Originally Posted By: bullwinkle
When the one in my GMC went out, it required standing on the brakes with both feet to get it to stop, and power steering also lost assist when you stood on the brakes. A reman PS pump & hydroboost, with Red Line PS fluid, took care of it, the old PS fluid was BLACK!


I don't cut the wheel braking in this beast, its a bad idea. But for testing purposes off to a parking lot I go.
grin.gif
 
I get that sometimes as well in the Yukon, not sure what it is but I changed hydroboost (leaking) and a line and its better but, still does it sometimes.
 
If the master cylinder piston is bottoming out...A hydroboost will have a high but very firm pedal unlike a vacuum booster sinking to the floor.
 
Originally Posted By: clinebarger
If the master cylinder piston is bottoming out...A hydroboost will have a high but very firm pedal unlike a vacuum booster sinking to the floor.

Thats good to know. No doubt it was full of muck when I basted it.
 
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