Noisy steering pump
 

hi guys, blazer k5 1990, 5.7L
i just installed a new steering pump (acDelco) and when i turn the wheel when the truck is still the pump makes grinding noises.
I've followed the instructions about bleeding out air and i made sure the fluid is clear with not bubbles. plus the level is o.k
when it makes the noise the pressure line and the return line shakes. i even opened the cap to see the fluid and when the noise starts the pump makes a lot of bubbles inside the reservoir.
i took it out for a short drive, there's no noise while the truck is moving of course but i can feel a slight difference in steering, it's a little harder than before.
by the way the reason i replaced the pump is because i had a leak and i was unable to find its source.
any ideas guys what I've done wrong or what might be the cause of the noise?

There is still air in the system. If your fluid has foamed up, you need to let it sit until the fluid is clear again. Jack up the front end and put it on jack stands. Then cycle the steering side to side 20-30 times with the engine off. Keep an eye on the condition of the fluid in the reservoir. You need to get to a point where there are no more bubbles in the fluid. It might take a while. If the fluid keeps getting bubbles in it, you may have to wait for the bubbles to float to the top before you cycle it again.

i've been sitting in the truck for the last hour turning the wheel.
for 95% of each turn the fluid is still and on the last squeeze there's a big bubble coming out. sometimes the reservoir even pukes out some fluid.
the thing is that the proccess looks endless. it seems like the pump is sucking air from somewhere. could it be that it sucks air in from the pressure hose fittings or o-rings?

If the engine isn't turning, the pump isn't doing anything but allowing fluid to move through it when you manually turn the steering wheel. One of the connections on the high pressure line could be leaking, allowing air in, but that should show up as a leak when the pump is running.

It can be an exercise in patience to get a power steering system bled out. Any amount of air will cause the system to froth. After that happens, it just gets worse from there. That is why you want to get all of the air out of it before you start the engine.

ok.. so the fact that i also tried this with engine on made things worst?
is it lost cause or it just gonna be harder for me to bleed out the system?
i will probebly buy a new hose this week just to be on the safe side, but i would like to hear your answer for the question above, i don't want to do any more damage to the new pump, plus if there's anything else i need to know to avoide damaging the pump i would love to hear it :) oh and most importantly - how will i know the bleeding process is over? there will be no more bubbles? should i leave the cap on while bleeding or should it be open the entire process?
sorry for the batch of questions, i just want to do things right :)

It definitely made it a bigger hill to climb by trying it with the engine running. I doubt that you will need a new hose if it isn't showing signs of leaking.

Once the fluid has frothed (got all bubbly), you have to wait for it to settle back out. This can be a long wait sometimes, but you want to make sure that you aren't reintroducing air back into the pressure side of the system.

If you need to, you can take the return line off the back of the pump and put it into a separate container. Then plug the port in the back of the pump where the return line went (section of hose with a bolt in the end will do this effectively enough). Then have someone cycle the steering lock to lock for you as you pour fresh fluid into the reservoir keeping it topped off at all times.

If you decide to try this method, you'll need quite a bit of power steering fluid. You will also have to be quick about putting the line back on the back of the reservoir. It'll be a bit messy, but if you are quick, not too bad.

someone told me that the fact that i took the truck for a spin, and even starting the truck without bleeding out proparly i've already burned out the pump and i should replace it.. how much truth is in that statment?

If there was a lot of air in it and you took it for a long drive, you wouldn't have done the pump any favors, but I doubt you ruined it. Try the method I stated to get it all bled out and see if that doesn't get you somewhere.

i got two parking spots, and my father insisted to move the truck to the other one and surprise surprise the pump was dead quiet. it only made noises when the steering wheel was locked to side.. what is that mean? that most of the air bled out itself over night? even possible?

OK, another turn of events, after work i wanted to hear if the noise is really gone, so at first the pump was quiet but after two minutes of turning the wheels it started to make noises again, engine is off, cap is open, the pump is making noises but i cant see bubbles so how will i know if the bleeding process is happening? must importantly - i need to determine if the pump is bad, if so i need to take it a part and send it back to the U.S and i really don't want to do that without being 100% sure it's bad.
it would be a shame to send it back just for not bleeding air right...

p.s - how come i see two kind of approaches - the one is to bleed air with engine off and the second on, any explanation for that?