You lose control of the steering.
Its has HydraBoost Braked, operates off the power steering pump.
Sounds like vehicle is stalling and you are losing all power assist and vacuum supply to braking system
Not a good idea, you will lose the power steering and power brakes.
You will lose your power steering and tho you still have brakes your ABS may not function
Depending on the type of vehical, a hydomatic system works with the brakes and power steering, thus one gives out the other may stop working as well.
If your vehicle has abs brakes, just apply the brakes hard and steer away from danger. If the vehicle does not have abs brakes, try to apply the brakes without locking up the wheels and going into a skid then steer away from danger. If you lock up the brakes and go into a skid you will lose control of your steering.
You most likely have an issue with the Vacuum brake booster has an internal leak. Typically you can hear it inside the cabin when you step on the brake pedal. You r vacuum booster uses vacuum to ampify the power of you leg pressing on the brakes and internal vacuum leak casues the engine to lose too much vacuum thus affecting your engines RPM.
Your Suburban likely has hydro-boost power brakes which are hydraulically powered by the power steering pump. If you lose assist to one, the other loses as well.
The engine shuts down, you lose the power assist steering, power assist brakes and you coast to a stop.
You will still be able to steer the vehicle, but it's going to take lots of extra effort ... same is true of the brakes - more pressure is going to be required if you lose engine power.
Loss of brakes