Why does my power steering pump make so much noise when I have my foot on the brake when in park? The power steering has been off and on lately, do I need a new pump? I'll check for leaks and maybe flush the system later on, but is this a common problem? The power steering pump in question is on a 1990 4runner sr5.

Thanks!

I have the same problem, I also have the same year SR5. I've been wanting to try to fix it but have been waiting for nicer weather or to find an easy way to fix it from finding old threads on here.

Let's start with the basics, have you checked the PS fluid level in the reservoir?

Yes I've checked the resovoir and initially it was low. I've had to top it off again since then, but I haven't found any leaks.

I'm pretty sure mine is good too.

Can the power steering fluid degrade that much that just changing the fluid may help? From searching it seems like if the pump is not 100% and the fluid is real cold, which it is now, at least here, it has trouble pumping it. I haven't had the 4runner long and the first month I had it, it didn't seem to be doing it but now that its colder it seems to happen more. Even sometimes when the fluid should be warm which makes me think it may be that and/or something else. I also has a little play in the steering wheel before the 4runner responds, not sure if that's a sign or all runners are like that. This is the first SUV I've owned and not sure if the little bit of play before the steering responds is normal or not.

All fluids degrade over time and need replacing periodically, including the PS (which is ATF, not regular brake fluid). It may not be the answer to your current problem, but keep it in mind.

As for play in the steering wheel, some is normal, especially in an older vehicle. There's several things that could cause that.

Cold can slow things down too. Right now it's been 15-20*F in the mornings, and the auto trans in my Trooper doesn't like it for the first 5-10 minutes.

my 92 runner sr5 just started to make a squeeling noise when the truck starts up. it used to go away when everything got warmed up but now it does it constantly. is it time to start saving for a new pump?

You may want to start, but first check the belt to make sure it's in good shape and not loose.

belt is brand new

Replaced the PS pump, I figured I might as well do the most obvious thing first. Seems to have been the problem, had to replace the pulley as well. No more horrible noise and pulsing brakes.

Be super careful with the PS vacuum relay or whatever, mine broke as I was taking the pump out and I couldn't get a new one anywhere but the dealer.

Bumping this thread as it’s the only one I found with a similar problem as mine, and for some reason I can’t create a new thread..

Anyway, I started noticing a loud, high pitch squeal when I turn my steering wheel all the way in either direction. It also squeals when the brake pedal is pressed down ALL the way. This only happens when the engine is warmed up. It does not happen at all when it’s cold/warming up. I just got my brakes replaced and the fluid replaced a few months ago. (I’ve had the truck for 4 years, have no idea how long they went without replacing by the previous owner)

There is also a leak from my power steering pump which I’m going to fix, I have the seal kit and will start with the front and back seals and see if that stops the leak and the squealing.

Any other leads would be helpful. At first I thought it would be entirely PS pump related but because the squeal happens when the brake pedal is down all the way I think it might have to do with some vacuum lines.

Are the brake system and PS pump connected in any way via vacuum lines?

On the power steering the squeal you're hearing it is from the fan belt slipping that turns the power steering pump, the pump take more power to turn it when you turn the steering all the way and the pump is under strain, replacing the belt and making sure it's tensioned properly should stop the squeal, that being said I would avoid turning the steering wheel so hard at the end like that, it only wears out your power steering pump and belt faster and you're not going to get any more turning out of the wheels by doing so!!