Dexron VI OK in power steering?
09-08-2016, 12:10 AM
#16
Burning Brakes
My steering rack just vented it's fluid all over the garage floor while it was just sitting there...not running. Go figure...
Roger set me up with a reman rack, and I just loaded the system with this Pentosin CHF11s. The fluid is green and very lightweight. I filled the reservoir, did the obligatory turn of the steering wheel back and forth, lowered the car for a test spin, and the pump groaned mightily.... (the pump was rebuilt about 2 years earlier).
I immediately suspected the fluid (I don't speak nor read German) and elevated the car to drain the rack. Of course, I never checked the reservoir. Yup, it was empty. Duh....
Roger set me up with a reman rack, and I just loaded the system with this Pentosin CHF11s. The fluid is green and very lightweight. I filled the reservoir, did the obligatory turn of the steering wheel back and forth, lowered the car for a test spin, and the pump groaned mightily.... (the pump was rebuilt about 2 years earlier).
I immediately suspected the fluid (I don't speak nor read German) and elevated the car to drain the rack. Of course, I never checked the reservoir. Yup, it was empty. Duh....
09-08-2016, 12:56 PM
#17
Chronic Tool Dropper
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Looking back through this thread, I suspect that we are way over-thinking the subject. We are working on a (relatively) low-pressure hydraulic system, no combustion, no sensitive clutches or brake bands, no valve body. Just sliding vanes and a pressure relief valve as moving parts really. So unless the hydraulic oil or ATF you choose eats through seals or dissolves the reservoir it will be OK. ATF differs from normal hydraulic oil by the detergent additives, and the precise friction/lubrication needed for those clutches and bands.
Bottom line is that ANY Dexron, Mercon, or low-viscosity hydraulic oil will do the job. Want to minimize the risk of fire when there's a leak? Put in a high-flashpoint hydraulic oil. The power steering system is not rocket science.
Bottom line is that ANY Dexron, Mercon, or low-viscosity hydraulic oil will do the job. Want to minimize the risk of fire when there's a leak? Put in a high-flashpoint hydraulic oil. The power steering system is not rocket science.
09-10-2016, 05:22 PM
#18
Official Bay Area Patriot
Fuse 24 Assassin
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Fuse 24 Assassin
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Never had a problem with Dexron VI in both my transmission and my power steering.
IIRC Dexron VI is a more synthetic and refined than III.
IIRC Dexron VI is a more synthetic and refined than III.
09-13-2016, 09:50 AM
#19
Rennlist Member
Looking back through this thread, I suspect that we are way over-thinking the subject. We are working on a (relatively) low-pressure hydraulic system, no combustion, no sensitive clutches or brake bands, no valve body. Just sliding vanes and a pressure relief valve as moving parts really. So unless the hydraulic oil or ATF you choose eats through seals or dissolves the reservoir it will be OK. ATF differs from normal hydraulic oil by the detergent additives, and the precise friction/lubrication needed for those clutches and bands.
Bottom line is that ANY Dexron, Mercon, or low-viscosity hydraulic oil will do the job. Want to minimize the risk of fire when there's a leak? Put in a high-flashpoint hydraulic oil. The power steering system is not rocket science.
Bottom line is that ANY Dexron, Mercon, or low-viscosity hydraulic oil will do the job. Want to minimize the risk of fire when there's a leak? Put in a high-flashpoint hydraulic oil. The power steering system is not rocket science.
Would you be able to recommend a high-flashpoint fluid? I must admit I am not equipped with much knowledge of the the available fluids for the 928.
Cheers!
Carl
09-13-2016, 12:35 PM
#20
Chronic Tool Dropper
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Carl--
I'd have to go searching, but my search sources are very similar to yours -- It's probably the same stuff you have flowing around for IGV control in your work engines. Look for Aeroshell 31, for instance, as an option. It's not extremely expensive (typically less than $50/gal in 1-gal bottles) considering the added level of fire safety available. For stationary non-aero-derivative gas turbine engines, there are several non-aviation-rated fluids, but I just never see them in less than 55-gal drum sizes.
And FWIW, that stuff now gets dehydrated, filtered and polished on the way out of the drum, into a temporary transfer tank. There it gets the same treatment again in a circulating system, this time with heat added, to make sure it's clean before it goes into the system. We were doing that initially with just the main lubricating oils, but solved more than a couple erratic control issues under load by treating the hydraulic oils the same way. Turns out the dirtiest oil is the new stuff in the unopened drums.
I'd have to go searching, but my search sources are very similar to yours -- It's probably the same stuff you have flowing around for IGV control in your work engines. Look for Aeroshell 31, for instance, as an option. It's not extremely expensive (typically less than $50/gal in 1-gal bottles) considering the added level of fire safety available. For stationary non-aero-derivative gas turbine engines, there are several non-aviation-rated fluids, but I just never see them in less than 55-gal drum sizes.
And FWIW, that stuff now gets dehydrated, filtered and polished on the way out of the drum, into a temporary transfer tank. There it gets the same treatment again in a circulating system, this time with heat added, to make sure it's clean before it goes into the system. We were doing that initially with just the main lubricating oils, but solved more than a couple erratic control issues under load by treating the hydraulic oils the same way. Turns out the dirtiest oil is the new stuff in the unopened drums.