Power Steering getting noisy

[1996LandCruiser]

What is the troubleshooting procedure for the ps system? I have noticed an increased noise, low/dull continuous, level upon turning the wheel especially a low speed. (makes sense, right) The reservoir level looks ok but I have never changed the fluid or done anything else to the system. The ps belt looks to be ok too. Is there anything that typically happens on the FJ80s in regards to this?

Thanks, jt
-96 LC, close to 150k

 

[Tools R Us]

My first operation would be to change the fluid. I prefer a good hydraulic oil ISO32, like Mobil DTE Light, in my experience runs the smoothest and lasts well.

 

[Tapage]

My first operation would be to change the fluid. I prefer a good hydraulic oil ISO32, like Mobil DTE Light, in my experience runs the smoothest and lasts well.

Better than ATF .. ?

 

[Tools R Us]

Better than ATF .. ?

Yes, been using it in Toyota PS units for years, with great results. They came from the factory with hydraulic fluid, ATF is the recommended refill fluid, most likely because it is common in automotive shops. The fluids are basically the same, with ATF having additional additives (friction modifiers, dye, detergent, etc) to deal with the clutches. Power steering is a pure hydraulic system, so those additives are unneeded, considered contaminants.

In my experience hydraulic fluid is more resistant to cavitation/noise, runs cleaner less varnish buildup, better handles stress/heat when pushed hard and overall runs smoother. I have seen several that had ATF and groaning issues, flushed to hydraulic fluid, the issue disappeared and the customer comments were "it's smoother than ever."

 

[TLCnoob]

CDan suggested that I use Downey to quiet the groanining. I tried it (Downey Free, don't need dyes or fragrance) and she's been all quiet for a year now. He mentioned the silicone as the secret ingredient. New fluid's best, but fabric softener might quiet the system until you're ready to do the exchange.

 

[nat88toy]

Fyi the power steering on your 96 is driven by the crank not a belt
I would drain the system and fill it with moble1 dte24 hydro fluid

 

[d0ubledown]

What is the troubleshooting procedure for the ps system? I have noticed an increased noise, low/dull continuous, level upon turning the wheel especially a low speed. (makes sense, right) The reservoir level looks ok but I have never changed the fluid or done anything else to the system. The ps belt looks to be ok too. Is there anything that typically happens on the FJ80s in regards to this?

Thanks, jt
-96 LC, close to 150k

do you have a leak somewhere? check the DS frame rail behind the front of the front wheel, or above the DS axle tube. did you look in the res while the motor was on? any bubbling?

i had this problem last week, been slowly but surely losing PS fluid for a while. a full flush might be a bit more than you want to do for now...so what i did was to suck out what was in the reservoir (via baster or hand vacuum pump), pull the return line located on the bowl part of the res. and add a tip to it that can dump into a catch basin. jack the front end up, rest the axle on stands. crank the wheel lock to lock, several times. this will purge some of the fluid in the system, but not all since the pump isnt running. some disconnect the efi relay and crank the ignition intermittently, but i had no helper so i didnt bother. reattach the return line to the res, and slowly fill res with new ATF dex III fluid.

as the fluid flows in to the system, crank the wheels again lock to lock, while topping up the res. i did this about 3-4 times until the fluid stopped dropping. replace res cap, lower front end and start the engine. turn lock to lock several times to ensure all the air in the lines are purged. should be good to go now...

 

[Tools R Us]

CDan suggested that I use Downey to quiet the groanining. I tried it (Downey Free, don't need dyes or fragrance) and she's been all quiet for a year now. He mentioned the silicone as the secret ingredient. New fluid's best, but fabric softener might quiet the system until you're ready to do the exchange.

IIRC Downey has silicone in it, a great anti foam agent. The way I see it; by starting with ATF there are additives that are unneeded, the system isn't happy with them, causing cavitation, so the "fix" is to add more additives? IMHO better off to start with a cleaner oil that is better formulated to do the job.

 

[Tapage]

Interesting point about ATF .. I was under the impresion ATF have more resistance for hi temps and keeps the lubricity under more demanding situations ..

 

[Brian894X4]

The Mobile DTE stuff is interesting. It has at least a higher flash point than Mobil 1 ATF. But the viscosity properties of the ATF "appear" to be better 98 (DTE 24) verses something like 176 on the Mobil 1 ATF. However, I'm pretty confused on what that means, so don't take my word on it. Trying to research it, it appears that anything close to 100 is really good but over 100 is measured differently or something along those lines.

The only thing I'm not sure about with the DTE and maybe it's been hashed out elsewhere, is whether the seals on the Toyota system prefer any lubrication or chemical properties of Dextron type ATF verses the DTE hydraulic.

Interesting that many other power steering systems actually just basically use brake fluid from what I'm reading...obviously not the Toyota system, though.

 

[mmml4]

IIRC Downey has silicone in it, a great anti foam agent. The way I see it; by starting with ATF there are additives that are unneeded, the system isn't happy with them, causing cavitation, so the "fix" is to add more additives? IMHO better off to start with a cleaner oil that is better formulated to do the job.

I don't think the additives have anything to do with cavitation cosidering what cavitation is. I do agree that Mobil DTE oil light is very good oil.


You have one of a few problems IMHO, air getting into the pump, wrong or bad fluid or mechanical issues with the pump. The silicone will increase the surface tension of oil dropplets to reduce cavitation but thats only covering up the real problem.

 

[hdj81v]

is it ok to use a hydraulic oil ( oil 10 ) in the system

 

[Tools R Us]

I don't think the additives have anything to do with cavitation cosidering what cavitation is. ...

A little confused, please elaborate? This is how I understand it in this application:

Cavitation is vapor drawn in or formed on the suction side and imploding on the pressure side of the pump.

The fluid is a cocktail of chemicals, some can change how others react, but for the most part, the performance of each chemical molecule is mostly governed by it’s characteristics.

For this example will keep it simple, base oil and an additive water. The base oil has a boiling point of about 600F and water at 212F. The oil will pass through the pump without issue. As the fluid is pulled into the pump, the suction and turbulence at pump entry reduces vapor pressure/boiling point of the fluid and the water molecule flash boils into vapor. A fraction of an inch/second later it’s slammed under pressure causing the vapor bubble to implode. The implosion causes heat, some of the surrounding oil is consumed/burned, can pit metal, etc. It’s the number one cause of pump and fluid wear, causes most of the varnish deposits in hydraulic systems, etc. It very often happens because of vapor formed at the pump entry, with no leakage, outside vapor.

Mild cavitation can happen without being noticed, but the groaning that is heard is lots of implosions happening at the same time, any of it is destructive. The composition of the fluid has a lot to do with it, as the fluid ages it degrades and becomes contaminated, so fresh fluid is good. Also anything that increases suction will make it worse, like reservoir being mounted too far away or low, small feed line, screen, filter between the reservoir and the pump, etc. Ideally the reservoir is mounted over the pump with a large line going directly to the pump inlet, like it is on the FZJ80.

 

[mmml4]

Tools R Us

Not to be argumentitive but to say that the additives in ATF cause a sytem to cavitate is IMO somewhat overreaching (if the atf is in good shape). If this is the case then one could assume that all PS systems with ATF are cavitating, it may be true but hard for me to accept.

 

[Tools R Us]

Not to be argumentitive but to say that the additives in ATF cause a sytem to cavitate is IMO somewhat overreaching (if the atf is in good shape). If this is the case then one could assume that all PS systems with ATF are cavitating, it may be true but hard for me to accept.

I maybe misunderstood, didn’t mean to infer that all systems that run ATF have cavitation issues. ATF is the recommended refill by Toyota, so is acceptable fluid. ATF is hydraulic fluid with additional additives, the majority of drivers will never load the system enough to see the difference, so for most ATF will work fine.

In my biz, have done some hydraulic work, talked to manufacture engineers, they all agree that in a purely hydraulic system (like power steering) hydraulic fluid is a higher performing oil. None will warranty their systems if ATF is run in them, due to cavitation and varnish issues.

In my experience hydraulic fluid is more resistant to cavitation than ATF. Have had a bunch of Toyota systems that had ATF and groaning issues when run hard, simply flushing to hydraulic fluid eliminated it in most cases. Due to the local climate we probably see the groaning issue more than most, most probably don’t play in the rocks at 110F+!

If ATF is running well for you, run it. If you have issues or want a higher performing oil switch back to hydraulic. It’s not magic, wont fix mechanical issues, etc, but in my opinion/experience runs smoother in Toyota power steering systems.

 

[Brian894X4]

Are there any potential issues with the Toyota seals and hydraulic fluid?

 

[Tools R Us]

Are there any potential issues with the Toyota seals and hydraulic fluid?

None that I have ever seen, the fluids are very similar. On the boxes and pumps that I have built, seal wear has never been an issue, all that I remember were heat hardened.

 

[Kernal]

Tools R Us; My power steering started to whine again with the cooler temps outside. Can we use any similar hydraulic fluid like the Chevron Clarity or is the Mobil DTE better? (see link)
https://www.cbest.chevron.com/generated/MSDS/PDS7669422.PDF
The information says it is incompatible with zinc or calcium, does that mean we should flush the system before adding the hydraulic oil?

 

[Tapage]

when I swap out my old Toyota pump and run a TC type, my system was filled with STP power steering fluid .. and my pump was groaning as soon at it reach certain temp ( 120°F by my laser temp ) now I'm runing ATF and hope it handle the temp better .. my next step should be 68 hydraulic fluid ..