Power steering fluid

[JWJ]

Is it acceptable to use synthetic Mobil ATF for power steering fluid?

[rhodes2010]

I seem to remember a lot of discussion that only
products labeled power steering fluid should be used.

The banter went back and forth. For years people have been using ATF
in their PS pumps. I used to.

I switched to power steering fluid and have had no problems, and want to
say
that some leaks actually stopped.

[Matt L]

I bought some power steering fluid at the dealer.

[layback40]

Does the power steering fluid mix ok with the fluid already in the system? If its full of atf shouldnt you drain it first if you are going to use power steering fluid ?

[toomany MBZ]

While you're there... go ahead and flush the system, with power steering fluid and change the filter.

[Matt L]

I would recommend planning ahead and ordering the fluid online. The dealer charged me a pretty penny for the stuff, but I needed something, and I know that they have the good stuff.

[bustedbenz]

I just use local parts store no-name "Power Steering Fluid" and it works fine. Can't imagine using synthetic on so unlikely-to-wear-out an application, but I suppose it couldn't hurt anything. ATF was standard as PS fluid for years, but common M-B wisdom has been that those who got away with it, no leaks, were just lucky.

Either way, the anybody-who-sells-it "Power steering fluid" has never caused me any trouble.

[JHZR2]

IIRC the PSF is about $5/qt at the dealer. Id probably just suck it out of the reservoir a few times, and once near the end of the job, change the filter out.

Two quarts should be fine. Considering that ATF is $3/qt at walmart, the right PSF for $5 from the dealer seems like a decent deal...

[charmalu]

UMMMM, sucking it out of the reservor is good I guess. but what about the fluid still in the hoses and the steering box? how would you change it?

Plus not knowing what is in the system, the atf and ps fluid would be mixed together. may not hurt anything, Iam just saying.....

there is a thread where a total flush of the system is done. disconnect the return line, stick it into a gallon milk bottle (can see the fluid coming into it) and after sucking the old fluid out of the reservor. pour in the new fluid, have someone turn the steering wheel back and forth, while the eng is running. soon as you see the clean fluid, kill the engine. Install the new filter, and good to go. yes there is a filter in the resevor. might be a good idea to remove it first.

maybe Iam one of the lucky one`s, I have used ATF for the past 13 yrs w/o any problems.

Charlie

[JHZR2]

Valid points. I have a few assumptions, and of course are trying to prevent opening up hoses because of potential leaks or issues that may occur due to age.

ATF and PSF should be miscible and not create any sort of additive clashing, so even if the system has a mixture, so be it.

I am not a fan of turning the wheel with the car stationary on the ground, and jacking up is a pain.

I figure the reservoir has nearly the same volume as the rest of the system.

So my method (Ive not had a mixed fluid setup - ever w123 Ive had has used PSF) is to just pull the fluid from the reservoir in full, then use the car a bit. Over the course of a few weeks, I can easily doa number of changes and slowly change out the fluid and get the junk in the system flushed out. Near the end a filter replacement is smart because there will have been some loading into it during the fluid replacements.

The flush method you propose will likely be a superior process, if one desires to go through it. I selected my method because it allows for slow exchange of the fluid over time, without having to disconnect any parts or impart wear and tear on any items, I never run the risk of the system going dry, and have a greater surety of introducing new fluid slowly to the entire system over the course of the multiple changes, allowing junk to be deposited in the filter as cleaning slowly occurs.

[toomany MBZ]

To bleed the air out of the PS system, you need to turn the wheel back and forth. If you're not comfortable doing that while sitting on the ground, jack it up. I doubt you would want to guess if the system has been bled.

[charmalu]

I understand not wanting to open up the system, by removing old hoses with the possibility of creating a leak.
with the age on these old cars, I bet most still have the original factory hoses on them.

I changed my return line about 3 or so yrs ago. It would be wet or damp and oily looking once in a while. would wipe it clean, and get oily looking again. one morning I had the hood up, and the angle of the sun, could see check marks in the rubber. It was seeping through the hose. replaced it with MB hose. have to buy it by the meter though, and only need about 19 inches.

I still have the original high pressure hose, would hate to have it go. haven`t heard of one going yet here on the forum. I do think the ends can be unscrewed and used on another piece. one screws on the outside and the other screws into the center to make a tight fit. not sure if MB sells that hose naked or complete with the ends.

I should have said above, to raise the vehicle to turn the wheels. Iam not one to turn them stationary either. I have 5 floor jacks, so not a problem to raise. though I might do this flush out by the barn over the gravel incase I miss my mark into the bottle .

what I have seen at PNP, I doubt many systems ever get flushed, most look like my morning coffee .

Charlie

[vstech]

it's simple to flush out. clear out the reservoir, change filter, fill with quality fluid, loosen belt, and remove, then loosen return hose and remove. put cap on nipple for reservoir. put return hose in milk jug. spin pulley by hand. when fluid gets clear exiting the return hose, you're done. (keep reservoir full...)

[toomany MBZ]

^That's a good idea, a one person operation, with complete control.
I've drawn arrows to the low pressure hose where I put the puke tank. I used that location as opposed to possibly damaging the fitting on the pump itself.

[vstech]

yup, that's where it's simplest to work it.