Power steering /brakes strange noise

Hello everybody
My power steering and brakes work just fine but ... When engine is cold there is a low hissing sound coming from pedals area that changes or goes away while depressing brake pedal ,other than that everyrhing works just fine.When engine fully heats up I start noticing low sort of whining sound.When I start turning wheels or depressing brake pedal becomes pretty loud.It gets worst when I drive,turn and brake at the same time.I can turn wheels with one finger so I'm not sure if it is power steering pump that started going bad but still works.Not sure .
Any suggestions from experienced humvee owners would be greatly appreciated.

The cheapest and easiest (well kinda) thing to try first is to bleed the system.

1. First check the level of fluid.
2. Jack up the front end till the tires are off the ground.
3. Engine off: Then turn the steering wheel from stop to stop (left to right), pausing a couple of seconds at each stop till you have done this left/right complete cycle 40 times. Yeah, quite the workout!
4. Don't think of doing it less than 40 times - this is super important. And the couple of seconds at each stop it important also
5. Check the fluid level. If you notice bubbles in the fluid then do this procedure again.

It could be the Cadillac valve, unplug it and see if the sound changes.

FlameRed said:

The cheapest and easiest (well kinda) thing to try first is to bleed the system.

1. First check the level of fluid.
2. Jack up the front end till the tires are off the ground.
3. Then turn the steering wheel from stop to stop (left to right), pausing a couple of seconds at each stop till you have done this left/right complete cycle 40 times. Yeah, quite the workout!
4. Don't think of doing it less than 40 times - this is super important. And the couple of seconds at each stop it important also
5. Check the fluid level. If you notice bubbles in the fluid then do this procedure again.

Click to expand...

Is step 3 wiith the engine running?

FlameRed said:

The cheapest and easiest (well kinda) thing to try first is to bleed the system.

1. First check the level of fluid.
2. Jack up the front end till the tires are off the ground.
3. Then turn the steering wheel from stop to stop (left to right), pausing a couple of seconds at each stop till you have done this left/right complete cycle 40 times. Yeah, quite the workout!
4. Don't think of doing it less than 40 times - this is super important. And the couple of seconds at each stop it important also
5. Check the fluid level. If you notice bubbles in the fluid then do this procedure again.

Click to expand...

thank you, I forgot to mention this is 2001 M1097 A2 .
I was trying to upload video with these sounds but for some reason I can not.
I'm going to try to upload it on YouTube and post the link here.

dmak said:

thank you, I forgot to mention this is 2001 M1097 A2 .
I was trying to upload video with these sounds but for some reason I can not.
I'm going to try to upload it on YouTube and post the link here.

Click to expand...

That is definitely pump noise, be careful when you push hard on the brake pedal as you can blow out the seals in the hydraboost if they are a little weak.
Also it is not a good idea to go all the way to lock on the steering while running as it causes a spike in the pump pressure.
Do the mentioned "cure" for air in the system.
Did this just start or are you just now getting your truck up and running?

Mogman said:

That is definitely pump noise, be careful when you push hard on the brake pedal as you can blow out the seals in the hydraboost if they are a little weak.
Also it is not a good idea to go all the way to lock on the steering while running as it causes a spike in the pump pressure.
Do the mentioned "cure" for air in the system.
Did this just start or are you just now getting your truck up and running?

Click to expand...

I'm getting this truck up and running.
I have no leaks on power steering
I'm going to try to release air from the system and if that won't help my next step would be new fluid since this truck still has old fluid in the system.

spankybear said:

Is step 3 wiith the engine running?

Click to expand...

Engine off. Sorry, I should have included that important info!

Finally this weekend I had time to get down and dirty with my power steering issue.
After replacing fluid which was not that bad and bleeding the system from air I noticed that air bubbles would not stop forming.
I inspected everything for leaks and found nothing leaking.Since clearly air was getting sucked in and I could not tell where. I went to autozone and bought power steering 3/8" hose and replaced return line from the cooler to steering gear which looked bad in shape, then did bleeding and still was getting bubbles(much less ).
After that I replaced reservoir to cadillac valve and still was getting bubbles.
Finally after replacing cooler to cadillac valve hose bubbling completely stopped.
I did few extra lefts and rights with wheels just in case .
I did some driving and pump is super quiet.
I'm super happy that I do not have to replace any expensive parts.
Thank you everybody for suggestions.