My grandma used to drive an Oldsmobile... She went through several cars in the time we lived close together. One thing I will always remember about her olds ( and every other olds I've driven or ridden in) is that her power steering always had a hum... Almost like you could hear the fluid moving through the pump.

I've never heard it on any other car except the olds, until my 06 f250... Never heard it on my 03. I checked the power steering fluid reservoir and its about half full... Can't find any fill lines on it, but there's a dipstick on the base of the cap, which is about half covered in fluid. No markings on that stick, though.

Any thoughts on cause for the noise? Most noticeable when going around a tight turn at very low speed (idle, basically).

 

I would try a Power Steering/Hydro Boost Flush

Supplies needed:
- 2-3 quarts of fresh Mercon/Dexron III ATF (or a synthetic ATF meeting those specs).
- 3/8" inside diameter tubing, at least 3 feet, more is fine.
- shop rags.
- waste oil container (an empty milk jug works great).
- hand vacuum pump or turkey baster (don't use the one from the kitchen or you'll hear about it ) - I used a small syphon hose.
- pliers (to loosen spring hose clamp)
- step stool, tire step, etc. (optional but makes it easier to get at everthing from the side of the truck.)
1) Using a hand pump or turkey baster, suck all of the old fluid out of the power steering reservoir.
2) Fill the reservoir with fresh fluid.
3) Locate the hose that goes from the power steering reservoir to the brake master cylinder. This is a low pressure hose that just uses a spring hose clamp to hold it on to the brake master cylinder, near the top, right behind the brake fluid reservoir.
4) Remove the PS hose from the top of the brake master cylinder and attach a piece of 3/8" I.D. tubing to the nipple on the brake master cylinder and route the tubing to a waste container.
5) Fire up the engine.
6) Pump the brake pedal a few times. This will force old fluid out of the system into the waste container.
7) Top off the power steering reservoir with fresh fluid.
8) Repeat steps 6&7 until you've put 2-3 quarts of fresh fluid into the system.
9) Shut off the engine.
10) Replace the hose on the brake master cylinder.
11) Ensure power steering reservoir is at the proper level.

some pics and stuff here
Ford Super Duty Power Steering Flush | Superdutypsd.com

 

Man, that sounds easy! I'll give it a shot... Do you have similar instructions for a brake line flush? I've heard they're important, but everything I've seen has been just general description and not detailed step-by-step...

 

Here is a decent video on Power steering flush:

 

If you look closely, at first he set the hose just up in the air. At the end he mentions to zip tie the hose up higher.

Look closely, he made a mess when the hose wasn't zip tied.

So, ZIP TIE IT UP!!!

 

Just did it this morning - very simple and painless ;-)

 

Yes do this^^^

I Learned the Hard way

I didnt have any of the right Tubing so I thought i was going to pull a fast one and use a Peice of Funney Pipe with a Hose clamp that Idea Sucked LOL I got Oil Everywhere LOL

So DO NOT USE SPRINKLER PARTS LOL

 

Dave there isnt much to Brake Fluid Flush

Just did it Last weekend

1. First I took my ShopVac and Ducktaped a Small Tube to the End of it and sucked the Brake Fluid reservoir out

2. Filled Reservoir with new Dot 3 Brake Fluid

3. Started with the Farthest wheel (Passenger Rear) and Put the Hand Vac Pump/brake bleeder setup on it and sucked fluid till clear new fluid ran out

4. Same thing Driver rear wheel

5. Same thing Passenger Front wheel

6. Same thing Driver front wheel


Just make shure you keep checking the Master Cylinder so you dont suck air into the lines. Good thing about these truck that master cylinder is Big so you can suck a fair amount before you need to add more

If you dont have a Pump you can also do with 2 people one to pump the pedal and other to Open/Close the bleeder. This is the Fastest way

You Can Also do the Gravity method Since our Master Cylinder is the Highest point in the Brake system where you open the bleeder and gravity will pull the new fluid from the reservoir into the brake lines just check the reservoir every few minuites. this method takes awhile but does it by itself

 

Cool, thanks man! I realized today part of that hum is coming from the brakes, so I'm sure they need to be flushed also.

 

my 06 F350 did this very same thing for a few years make sure your lines are not starting to leak! I had replaced my hydrobooster and the pump 3 times I finally ended up with a Ford motorcraft reman pump and a used hydrobooster I bought of ebay along with a new pump side and return side line to the hydrobooster from the pump and that finally fixed the noise