My power steering reservoir has foamy bubbles and my disco is making a humming/buzzing sound when I turn the wheels. It looks like one of the lines might be leaking. If there is are causing the reservoir to foam, how would I bleed the system? Would I need to replace the hoses or pump also? Any help you could give me would be great. I am thinking about doing something to it this weekend.

 

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Normal.

 

If it's foaming, then there is air in the system.

I am not 100% certain, but I think these trucks do not come with bleeder values on the power steering. Try jacking up the axle until the wheels have most of the weight off them (the tires still barely touching the ground though), leave the engine off, and turn the steering lock to lock (left to right). With no power and and slight pressure on the wheels, turning the wheel might push out more air in the system. Worth a shot. You might be able to pin point a small leak this way also, if it exists.