How's the fluid in your power steering reservoir look? Probably like mud, if you've never changed it out. And somebody along the line most likely put some power steering fluid in it, which can degrade your pump seals. It uses ATF (automatic transmission fluid).
Either way, if it's not clean and bright red, it's time to change it out. This might take an hour if you really take your time. You'll need another person, unless you have really long arms.
Put your truck up on jackstands so the front wheels are off the ground.
Get a turkey baster or somebody else's antifreeze tester and suck all the old fluid out of the reservoir.
Find the return line to your reservoir. It will NOT be a hard line, threaded connection. Just a nipple with a soft line and a clamp (first picture).
Undo the clamp, slip the line off, and put it into a jug that will fit down by your manifold and steering shaft (second picture; kind of blurry, sorry).
Get a piece of tube that you can seal the other end of (third picture) and put it on the nipple of the reservoir.
Now have your buddy start the engine and constantly turn the wheels lock to lock, while you pour clean ATF into the reservoir to keep it full. All that nasty brown fluid will coming shooting out into the jug. As you pour in the clean ATF, you'll notice what's coming into the jug getting clean and red.
When it looks nice and clean, shut off the engine. Remove the jug, replace the return hose on the reservoir and tighten the clamp. Fill the reservoir with more ATF to bring it up to the proper level, then start the truck again and turn lock to lock till the ATF in the reservoir is not foamy.
Your pump will groan a little bit while it's working the air out, but when the fluid in the reservoir looks clear, it should quiet down.
When it looks good and clear, make sure it's filled to the proper level again, keep turning lock to lock for good measure, then shut off the engine. Check the level after a minute or so, and make sure the level does not rise more than 5mm after you shut the engine off. If it does, keep cycling till all the air gets out.
Sometimes the system won't completely bleed till you've driven it with the wheels on the ground for a little bit.
Your pump will thank you.
Either way, if it's not clean and bright red, it's time to change it out. This might take an hour if you really take your time. You'll need another person, unless you have really long arms.
Put your truck up on jackstands so the front wheels are off the ground.
Get a turkey baster or somebody else's antifreeze tester and suck all the old fluid out of the reservoir.
Find the return line to your reservoir. It will NOT be a hard line, threaded connection. Just a nipple with a soft line and a clamp (first picture).
Undo the clamp, slip the line off, and put it into a jug that will fit down by your manifold and steering shaft (second picture; kind of blurry, sorry).
Get a piece of tube that you can seal the other end of (third picture) and put it on the nipple of the reservoir.
Now have your buddy start the engine and constantly turn the wheels lock to lock, while you pour clean ATF into the reservoir to keep it full. All that nasty brown fluid will coming shooting out into the jug. As you pour in the clean ATF, you'll notice what's coming into the jug getting clean and red.
When it looks nice and clean, shut off the engine. Remove the jug, replace the return hose on the reservoir and tighten the clamp. Fill the reservoir with more ATF to bring it up to the proper level, then start the truck again and turn lock to lock till the ATF in the reservoir is not foamy.
Your pump will groan a little bit while it's working the air out, but when the fluid in the reservoir looks clear, it should quiet down.
When it looks good and clear, make sure it's filled to the proper level again, keep turning lock to lock for good measure, then shut off the engine. Check the level after a minute or so, and make sure the level does not rise more than 5mm after you shut the engine off. If it does, keep cycling till all the air gets out.
Sometimes the system won't completely bleed till you've driven it with the wheels on the ground for a little bit.
Your pump will thank you.