any one have any good sugestions how to bleed the brake hidroboost(not sure how to speel it)? 99 suburban 4x4 3/4ton with 7.4 :eek:

DO you want to know how to bleed the brakes or the hydroboost its self? If its the hydroboost then all you need to do is jack up the front of the truck and turn your wheels lock to lock. Hydroboost is run off the power steering pump. It flows to the hydroboost unit before going to the steering box. So when you steer it back and forth a few times it will work the air out of the lines.

yes it is the hydroboost.tried that still no power steering at idle.run the rpms up to about 900 and everything works.

hmm what did you just replace?

I had that same issue with a 68 lemans I had, but it didnt have hyrdoboost. It was only cuz the pump wasnt spinning fast enought due to a low idle.

old hydro boost worked fine.it was leaking power steering fluid so i changed it.WRONG MOVE should of let it keep driping.

Sounds like air in the system to me. Poss. worng fluid. Or a bad part.
Try this
Take the weight off the tires, "eng. off" Turn the wheel lock to lock several times. Let it set a while, aprox 5 min. Do it again. Then try it with the eng. running. It might take awhile to get all the air out. You can also turn the wheel while applying the brakes "Eng. running" to help push the air out.

sounds like the accumulator is full of air, did you press the brake pedal while its was turned off?
if not , push the pedal with both feet about ten times. then start your engine and see if the accumulator primes up. if its working right you should have boost even with the engine off for about the first 5 pumps, it will get less & less the more you pump. repeat as nessary.

still not working.anybody have any more idea,s?