Power Steering Fluid
 

I had my steering box and pump rebuilt by Power Steering Services recently. For fluid they recommend whatever the particular mfg spec'd out. No specific brands or types were mentioned. I'm next door to a Walmart so I walked up and bought a couple of quarts of Prestone fluid. Specifically noted on the bottle that it met all of GM's requirements. I installed the box and pump as per PSS's instructions and had bad issues with air in the system and fluid when I filled it up. I worked the air out over the next few days and the system did operate wonderfully......except when idling around in the driveway when it acted a bit weird. The power part of the steering was slightly spotty. Over a period of days I searched around on the web on some major GM websites and GM's own brand of fluid seemed to be the best brand, but quite frankly people used all manner of things as fluid and "never had a problem". I decided to run up to the local Chevy store and get a couple of quarts for a flush but decided to contact Chip at Power Steering Services first and ask SPECIFICALLY what brand of fluid he recommended for my stuff. I noted that I was close to all the major auto parts stores and all the major brands of autos. His reply was that GM recommended dexron Type A transmission fluid but that Dexron III would be just fine. I was kinda surprised!! Anyway I took B-Man's (and others across the web) advice and bought a couple of quarts of the GM fluid. Another fellow named Jim Shea noted that GM has used it with good effect in a few million systems. Last night I flushed out the Prestone and refilled with the GM fluid. Even with a lumpy, "I just woke up idle" the GTO now magically has easy, smooth one finger steering.

Many of the folks like Lee's recommend GM steering fluid for their boxes. I think AGR recommends Royal Purple.

First Guess: it's not the brand of fluid that made the difference...you just managed to work the rest of the air out in the process of changing the fluid.




GM hasn't recommended trans fluid for the power steering for a long time.

David,

I too had my power steering box and pump rebuilt by Chip and I need to do this for my own car; so, I just want to make sure I understand.

Did you use:
GM Brand "Power Steering Fluid"
GM Brand "Type A Transmission Fluid"
GM Brand "Dexron III Fluid"
Something else?

Thanks!

All of these fluids are just basic hydraulic fluids. Some have more detergent than others. The transmission fluid varieties are specific to the clutch sets that are put into the transmission, but should not make any difference in a power steering unit although they may make the seals in some pumps expand more than desired.

X2.

Could be. I'd driven it probably 6-8 times for about 100+ miles over a period of 2-3 weeks before I went the GM fluid route. How long should it take to purge the air out? This was after following Chips refill/installation instructions to the letter. Then purging the pressure valve per his instructions. Then jacking the front of the car up and turning the wheels back and forth many dozens of times. All over a period of days as I tried to straighten it out. I did note in my searching around that more than one person said that the GM fluid is less likely to hold air.

They must have recommended trans fluid when this box/pump was made? Chip sure seems to like it.

GM power steering fluid.

I just had my Steering Box and Power Steering Pump rebuilt by Chip too.
On his General Suggestion Sheet he states in the second paragraph:

To start:Fill the pump/reservoir with power steering fluid(manufacturer recommended fluid)

Which would be Type A transmission fluid.

GM Power Steering Fluid Item #8902114 for 16oz bottle
#89020661 for 1qt bottle

I've used Dexron, then Dexron II, then Dexron III, now it's called Mercon as the Dexron ATF's are all obsolete. Anyway, I've always used GM spec ATF in mine for the past 30 years with no issues. I even have the original pump and gearbox on my '67 with 242,000 miles on the clock. The main trick is to have clean fluid and to have enough of it.

I don't think that was around when my car was made so it would be tough for them to recommend it. I'll look tonight to verify but I think in 1969 GM recommended Type A auto trans fluid.
The fluid I bought and installed was the 89020661 and using it seems to make sense. I found it fairly strange that Power Steering Services would simply state that you needed to use whatever the mfg recommended and let it go at that.

Because it doesn't make a lot of difference, and they're too lazy to provide detailed recommendations.

Do keep in mind that ATF has "evolved" over the years, it's getting thinner (lower viscosity) and it has increasing amounts of friction modifier to condition the wet clutches and bands in an automatic transmission, As it becomes more specialized for AT use, it may have become less suitable for PS use.

Given a choice, I'd happily use whatever aftermarket ps fluid happened to be "on sale" at my local parts house in every vehicle I own EXCEPT my Trailblazer--the power steering was noisy as hell in cold weather until I installed the "special" GM cold climate PS fluid (at $16 per PINT!) When I flush that one some years from now, I'm going to try ordinary aftermarket PS fluid, but if I have trouble (noise in winter)...it'll be back to the expensive GM stuff again.

As I read along, that's what I gathered. I read when GM worked with the PS fluid maker (Texaco?) to come up with it's fluid they wanted to address some of the drawbacks of A/T fluid in a power steering system. One of them being how A/T fluid was changing regularly to better work in a transmission. Also to reduce the possibility of holding air in suspension.

Thanks! for your input.

X2. I couldn't keep Dexron in the PS reservoir very long in my '59 after I brought it back from a 25 year nap. It got low again and I had a bunch of Type FA left over from changing the trans fluid on the 4 speed hydro, so I evacuated the Dexron and substituted Type FA. It never did leak a drop after that, and top of that, low speed performance ('59 389's idle at 480 RPM's) substantially increased.

Been using ATF in PS for 50 years. $5 bottles of Power Steering Fluid may be right for some modern cars but not an old Pontiac. I suspect that stuff is just overpriced atf anyway.