Hi folks, I have lurked around for a while and now I need some help from all of the "Toyota Experts".
I have a 1991 4runner, 4x4, 3.0, manual with ABS. When I bought it it had a slight whine when turning and braking. The whine got louder over a few weeks so I replaced the power steering pump with a reman unit. It did nothing to help the problm, and it continued to get louder. I bled the steering lines and got nothing. Next I replaced the ABS actuator with a used unit, bled the brakes, and the steering system to make sure I had no air anywhere. The problem got worse. Now my power steering works about 80 percent of the time and whines when it does work. It whines even worse while braking. When idleing it has a slight whine, but when braking it gets very loud. Has anyone ever experienced this? I have searched a lot and cant seem to find much to help. Any help would be appreciated.

 

First question, did you use ATF dextron lll or power steering fluid?

 

It has had Dex III in it for a while, from the guy before me. He had also replaced the ps pump at one point. Just recently when replacing the pump I switched to power steering fluid.

 

Dextron lll is the propler fluid. Power steering fluid will eat the seals out. It cost me a pump last year.

It got so bad that I had no power steering in parking lots or slow speed/rpm steering. It wined like crazy till one day it sent the shaft and pully into my radiator....

Stick with ATF Look on the cap of the power steering pump, it says to use ATF dextron ll

 

Thanks for the info. I was planning on switching back anyway because of the larger tires, and the consistancy of the Dex III. It did, however, start all of this with Dex III in it and it has only had ps fluid for about 3 weeks or so.

 

may I ask... would you put brake fluid into the hydraulic system on a bulldozer or other construction equipment?
... that's the equivalent of putting "power steering fluid" into a Toyota pickup.

 

Yeah, I get it, I was repremanded soon after the ps fluid was put in there. However, none of this solves my problem. The problem came about while the truck was running Dex III.

 

okay... just because you have experienced a problem once... when a certain fluid was being used...
... nevermind.
I guess you could put gasoline into the oil pan just "one" time, and even though the gasoline is gone, everything is fine because you are using oil now?

 

Does it blow fluid out the top of the resevoir? Because i had the same problem with my 90 p/u with the v6, even after bleeding the brakes and the gearbox and the only way i solved it was to jack the front end up and crank the the wheels back and forth like 60 times and it got rid of the problem.

 

How are you bleeding the system, specifically ?



Fred

 

Why arnt you listening to what Im saying? The problem has been around for a long time. Dex III has been used in the system for a long time. The problem started way before any power steering fluid ever went into it. The problem is not power steering fluid. I put power steering fluid into it 3 weeks ago, the problem has been there for months. If you dont have anything useful to add why are you insistant on trying to be argumentative? I understand the ps fluid needs to come out, but that is not the cause of the problem.
The problem started with DEX III months ago, BEFORE ps fluid was ever used.
If you have any useful information I am all ears.

I dont think it is blowing anything out of the top but I will double check that. I did try jacking the front up and turning the wheels before, like you did, but I didnt do it that many times.

I loosened the valve at the steering box jacked the front up and turned the wheels back and forth without hitting the stops. Some air was in the fluid coming out so I did this until the fluid had no more air in it. Did I do this the correct way? I didnt do it as many times as phil90 did though.

 

I would do try bleeding the system again.

Very odd problem. Have you checked out the gearbox itself? Sure the belts on tight?(gotta ask that one, sorry)

 

Please accept my apologies for the misunderstanding and my attitude. I misread what was written.

anyhow... if changing the pump and using the proper fluid hasn't helped...
I might consider the inner linings of either the pressure or suction hoses from the pump are separating from the casing and oscillating internally causing the noise. Given the power steering assist comes and goes (if I read your post correctly) I'd suspect something with the return line. I have seen this occur on hydraulic systems on tractors, so that's why I mention it. In the worst cases, the suction line collapses completely cutting off all fluid flow and consequently all of the lubrication to the pump, and since even when the pump isn't "doing" anything fluid should still be circulating within it, without flow the pump burns itself up.

 

Most Toyotas have a fine mesh screen at the bottom of the resevoir, if it gets plugged up the pump will cavitate. If your reman pump came with a resevoir ignore this tip

 

No, don't ignore it.

That's a good catch and such information is always helpful.

 

No problem at all. I am running Dex III now, as well, so we should be good in that department. I will check out the hoses and see what I can do there. Thanks for the tip.

I will check this one out too.
After I have checked the hoses and the filter I will bleed the system again. we will see how it goes.