OK guys, I have a B7 with hydroboost hyd. brakes that has the pump that is for both the P/S and the brake booster. I changed the booster unit because of a problem and everything was ok for about one week. Then the brakes were failing and the steering was hard. Told the driver to park it and drive a spare and I ordered a pump. Well when I got it in the shop I found the resivior was empty. So I filled it up and started it and found a leak on the pressure line coming from the pump. Replaced the line and I am having trouble with air in the system. I will start it up and run it for about 5 minutes and it will foam up so bad that when I sut it down the resivior over flows. I have done this several times with about 30 minutes between, thinking the air would work out of it. No dice! So I bought a supply line that goes from the resivior to the pump. Will be putting this on in the am. Am I on the right track? It must be getting the air from some where. Thus the supply line.
There will be air in the entire steering/hydroboost system. To bleed it out, lift front wheels off of the groung enough to take pressure off when turning them. Refill the resivour and start the bus. Turn the wheels slowly back and forth. Do not force them to the stops. It may take a couple of times like this. Let is rest in between to defoam. After a couple of times try to apply the brakes; this will help release any air in that part of the system. It will eventually work its way out.
I remember them being a real bugger because the hydrobooster is at the highest point in the system. It took me both brake application, steering wheel turning and perserverance to bleed. You got to get to the point that it has enough fluid in it so pump doesn't suck air and enough air removed so it doesn't overflow the resevoir when you shut it down.
I think I found the problem. I replaced the supply hose. Then it blead out ok. This isn't my first time around block with these things it's just that this one was being quite the "bugger". Thanks for all the input guys. Maybe someone else will benefit from this thread in the future.
Chevy B7 with air in P/S system
Posted - 01/10/2011 : 2:01:29 PM
