Noise after vertical climb

[thompsoncustom]

Was going up a hill which was really steep maybe 60% grade/angle (90% being straight up and down). I noticed some noise from the engine compartment kind of thinking it is power steering related but got leveled out and the noise continued. Decided to drive home about 10 mins away and the noise was gone so my question is does the power steering pump run drive somehow or is there other issues caused from such steep inclines?

 

[peggrw]

Seems obvious but would be checking the levels of both your power steering and automatic transmission. Noticed mine did the same thing running up the mountain when I first got it. Adding a little of the correct fluid in the power steering reservoir fixed that whine. I could see the same thing happening with an automatic transmission but have little experience with transmissions, so what do I know?

 

[thompsoncustom]

I know the tranny fluid is correct and full as I changed it.

the power steering on the other hand could be the wrong fluid as I have not change that and I got it from someone not a military base.

I see there appears to be a reservoir on the top with a sight glass and the fluid is above that level.

 

[thompsoncustom]

well never did figure this out made sure the fluid was good and full. climbed with it again today and getting the same noise after climbing.

I did notice on the way home that pushing hard on the brake pedal makes the noise worse. will have to look into that in the morning.

 

[Valley Rock]

I would think that pushing hard on your brake pedal is asking more of the pump to run the hydoboost, so maybe it's crapping out on you or has a plugged return filter

 

[thompsoncustom]

I would think that pushing hard on your brake pedal is asking more of the pump to run the hydoboost, so maybe it's crapping out on you or has a plugged return filter

Maybe it's on it's way out but I'm still not sure why it only makes noise after steep hill climbing and then goes back to normal with enough time.

 

[Mogman]

You are getting air in the system somehow, do not just stomp on the brakes to test the noise, you can blow out the seals in the hydroboost, don't ask how I know...
I would not be overly concerned as long as the steering and brakes still work and it goes back to normal and there are no leaks.
You might want to double check all of the return lines clamps to make sure they are tight.

 

[thompsoncustom]

You are getting air in the system somehow, do not just stomp on the brakes to test the noise, you can blow out the seals in the hydroboost, don't ask how I know...
I would not be overly concerned as long as the steering and brakes still work and it goes back to normal and there are no leaks.
You might want to double check all of the return lines clamps to make sure they are tight.

ya I would assume the same, after trying to bleed the air out of the system this morning I opened the reservoir this afternoon and no signs of bubbles or foaming so the engine must only suck air when the engine/frame move alot.

I did notice that the short peice of rubber right off the bottom of the reservoir is new but the rubber closest to the pump is not. I tightened all of the hose clamps up tho so that might fix it otherwise the older hose might have some dryrot that when flexed is sucking air.

 

[thompsoncustom]

update: replaced the power steering cooler lines as they were the only ones I found that were questionable and bled the system.

climbing with it today it started whining right away so I guess I'll replace the rest of the 3/8 line even tho they look good just to rule it out.

anyone know what line I need that runs from the reservoir to the pump?

 

[TOBASH]

One would think that going uphill would be beneficial for bleeding the system because bleeding the system the best way requires jacking up the vehicle to at least 15° and then starting the engine and turning the steering wheel lock to lock and back 20 times.

 

[thompsoncustom]

ya if it wasn't sucking air when i was doing it I'm sure it would be great to go up and down sharp inclined to help get trapped air out. The oil cooler being higher than the lines running to and from it would be a area I would think air would get trapped but going down a step decline would put the hoses higher and make it easier for the air to get out.

 

[thompsoncustom]

well I'm done chasing my tail on this issue figured it out.

Happens to be a design flaw with the power steering reservoir. I assumed the pump sucked from the center of the reservoir and the return lines were on the outside but it's the opposite and what's worse is the feed line to the pump is on the front of the reservoir (pointed to the front bumper) so when the humvee is point straight up in the air (even when completely full) the air in the reservoir is sucked into the pump.

could be fixed by cutting the nipple off of the reservoir for the pump and relocating it or by turning the reservoir pump barb to point toward toward the fender.

 

[Retiredwarhorses]

This same thing happens almost every time I load a truck onto a trailer, as soon as it crests the top the pump whines….its as you pointed out, never an issue on rcsk18330 equipped trucks.
Do your have your filter installed?

 

[thompsoncustom]

ya filter is in there. I might just end up modifying the reservoir so it doesn't suck air unless the humvee was tipped on its side.

Added: after looking at it I think it would be easy enough to cut both barbs off the bottom and switch them around and weld it back up.