Another power steering question...

[trouser_trout]

Hi All,

I'm hoping one of you can help me. My power steering pump whines when I am going up steep hills. It doesn't do it any other time. I have plenty of fluid, no leaks.

Any ideas what could be causing this and how to fix it?

Thanks,

TT

 

[cruiserman]

How do you know it's the PS pump?

 

[trouser_trout]

How do you know it's the PS pump?

Well, when I was on the steep incline, the pitch of the whining sound changed when I moved my steering wheel back and forth. Could it be something else?

My mechanic has my truck right now and can't find anything wrong. He doesn't have access to a steep enough hill to see/hear the problem for himself. He actually recommended I post this question on MUD to see if anyone else had experienced this issue.

Thanks,

TT

 

[cruiserman]

Maybe it's starving of fluid due to the hill.

 

[1911]

Assuming you know that the PS pump takes ATF and NOT PS fluid. When I bought my FJ80, the PO had put PS fluid in it and it whined badly when the temperature was cold or under load like turning the wheels w/o the truck moving. A flush 'n fill per the FSM with (synthetic) ATF made her purr like a kitten under any load or temp.

 

[vegas80]

could someone post or email me the flush and fill directions per the FSM? Mine is whining and has PS fluid in it. I want to change it out and get the Synth. ATF in there. Thanks!

 

[Tapage]

mmm why not use Power Steering fluid in a Power Steering pump . ? are not logical .. ?

So in a local PS shop when I'm dealing with mu 60 series PS system, the chief show me the posibility to use 40 oil in my PS system .. and after they rebuild my PS pump and steering box and fill my system with 40 oil ..

It's recently .. maybe one moth .. so in a few moth I can get more detais and report about it.

 

[1911]

could someone post or email me the flush and fill directions per the FSM? Mine is whining and has PS fluid in it. I want to change it out and get the Synth. ATF in there. Thanks!

From memory; FSM not handy at the moment.

1. Raise front of truck on jack stands so that front wheels are off the ground (not absolutely necessary, but makes the job easier).

2. Drain reservoir by disconnecting pump feed hose from bottom of rservoir. Reconnect hose. This is a good time to replace the hoses if they are suspect at all.

3. Disconnect return hose (higher hose on reservoir). Plug return nipple on reservoir with a rubber plug or crimped piece of hose.

4. Remove radiator puke tank and set aside.

5. A one-pint sour cream cup will deform just enough to fit between the battery, radiator, and PS pump, below the level of the pump. Do this. It's a tight fit. It would be possible to use a larger reservoir on the floor underneath the truck I guess, but it would be (more) messy. It's a messy job anyway.

6. Fill the PS reservoir almost to the top with new synthetic ATF. I've used Mobil 1 and Amsoil and like them both. The whole system only holds about a quart, but you'll need at least two and maybe three depending on how careful you are when bleeding the system (below).

7. Have an assistant BRIEFLY start the truck and shut it off within a second or so while you direct the return hose into the one pint sour cream cup. Have a good light shining into the reservoir. Watch carefully, and be prepared to yell at the assistant because it only takes like 1 to 1.5 seconds to drain the reservoir. DO NOT drain the reservoir all the way; always stop well before it gets to the bottom, else you will introduce more air into the system and have to start over again! Refill the reservoir with more fresh synthetic ATF. Drain the sour cream cup as needed and replace it in position.

8. Repeat step 7. until a) all of the ATF coming through the return hose is new, red, and sweet smelling, and b) there are no air bubbles or more likely foam coming out of the return hose. It will only take three or four times opf step 7. IF you are careful not to drain the reservoir. The last time you refill the reservoir, only fill it to the mark on the little dipstick.

9. Remove the plug on the return nipple of the reservoir and reconnect the return line, as quickly as possible. I always make a mess. Replace puke tank.

10. Almost done - hose off mess with brake cleaner, start truck, inspect for leaks, and slowly turn the steering from stop to stop a few times. This will finish bleeding the system. If you have done everything right, your reservoir fluid will be liquid and all will be smooth and quiet. If the fluid is foamy, you screwed up Step #7.

11. Remove jack stands, take it for a drive, and revel in the new smoothness and quiet of your much-improved PS.

One or two bananna job.

 

[1911]

mmm why not use Power Steering fluid in a Power Steering pump . ? are not logical .. ?

1. Because Almighty Toyota Engineers designed it to use ATF (much thinner than typical hydraulic fluid) and specify so on the filler cap and in the FSM.

2. Because it will whine and complain if you use too viscous of a fluid.

But it's a free country; use whatever you want in yours.

 

[Rookie2]

7. Have an assistant BRIEFLY start the truck and shut it off within a second or so while you direct the return hose into the one pint sour cream cup. Have a good light shining into the reservoir. Watch carefully, and be prepared to yell at the assistant because it only takes like 1 to 1.5 seconds to drain the reservoir. DO NOT drain the reservoir all the way; always stop well before it gets to the bottom, else you will introduce more air into the system and have to start over again! Refill the reservoir with more fresh synthetic ATF. Drain the sour cream cup as needed and replace it in position.

For a much slower and controlled process, you can flush the system and keep air bubbles out by not starting the vehicle, and just run the steering wheel from stop to stop... then get out and refill the PS reservoir and repeat until the fluid is red like new ATF.

RT's got a good write-up on this around here somewhere's. You use clear hose run into a container of your choice, so you can see the color of the fluid as you run through the process. Don't see the need for synthetic in this application, it's just going to leak/seep easier.


Rookie2

 

[Tapage]

1. Because Almighty Toyota Engineers designed it to use ATF (much thinner than typical hydraulic fluid) and specify so on the filler cap and in the FSM.

2. Because it will whine and complain if you use too viscous of a fluid.

But it's a free country; use whatever you want in yours.

Why thinner ( and just wondering, I'm not a expert .. all my comment are based only in my experience ) thinner less press ?

Less press means les power steering .?

 

[1911]

Why thinner ( and just wondering, I'm not a expert .. all my comment are based only in my experience ) thinner less press ?

Less press means les power steering .?

I don't know why Toyota designed their power steering pumps for ATF, but since they are designed that way, if you use any heavier thicker fluid it will not flow at the rate the system needs and it will complain by whining and groaning under stress.

Less flow = less power steering.

 

[Tapage]

I don't know why Toyota designed their power steering pumps for ATF, but since they are designed that way, if you use any heavier thicker fluid it will not flow at the rate the system needs and it will complain by whining and groaning under stress.

Less flow = less power steering.

I will take a chance this weekend making a test with my HDJ-80 PS system ..

 

[Rich]

From the specs I have seen typical ATF fluid and typical powersteering fluid run pretty much the same viscosity.

 

[1911]

From the specs I have seen typical ATF fluid and typical powersteering fluid run pretty much the same viscosity.

You've got more hard data than I do. I all I can say is that from personal experience, running power steering fluid in an FJ80 pump consistently produced a chorus of groans and whines when the ambient temperature was below 40-50 degrees or when the steering was turned in the driveway without the truck moving forward or back, and that changing out the same truck with Toyota-specified ATF made it quiet and smooth as buttah at any temperature or use. Use whatever you want to in your truck.

 

[vegas80]

From the specs I have seen typical ATF fluid and typical powersteering fluid run pretty much the same viscosity.

I don't know what the viscosity difference is, but it's there! I just finished draining and refilling with Mobil 1 synth ATF. whining is completely gone and steering feels much smoother. Thanks for the help everyone. and as posted above, definately a job. I was in and out in less than an hour.

 

[Rich]

Replacing the fluid from time to time is always a good maintenance practice. While Toyota specifies dexron ATF fluid, I suspect that the factory fill is power steering fluid.

 

[sseaman]

You've got more hard data than I do. I all I can say is that from personal experience, running power steering fluid in an FJ80 pump consistently produced a chorus of groans and whines when the ambient temperature was below 40-50 degrees or when the steering was turned in the driveway without the truck moving forward or back, and that changing out the same truck with Toyota-specified ATF made it quiet and smooth as buttah at any temperature or use. Use whatever you want to in your truck.

have many of you noticed with the temp change?

 

[Tools R Us]

I don't know why Toyota designed their power steering pumps for ATF, but since they are designed that way, if you use any heavier thicker fluid it will not flow at the rate the system needs and it will complain by whining and groaning under stress.

Less flow = less power steering.

If the system is designed for ATF why is the factory fill hydraulic fluid?

What benefit would a pure hydraulic system gain from the friction modifiers and detergents put in ATF to deal with the clutches? Is the ATF refill recommendation a design thing, or convenience thing, like all shops have ATF and it will work?

I have had very good results running Mobil DTE light hydraulic oil in Toyota power steering systems. In my experience it works smoothly and is much less likely to whine when worked hard.