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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: Lin on February 21, 2019, 09:24:42 AM

Title: Mixing Fluids in Power Assist Steering
Post by: Lin on February 21, 2019, 09:24:42 AM
My 5a has hydraulic power assist steering.  I have always used automatic transmission fluid in it.  I liked that it was a different color than motor oil to help with leak detection.  The system now uses oil, and I have not been able to find where it is going.  I have been thinking to switching to 30w motor oil and wonder if I can just add the 30w oil to the system as needed, or would draining all the transmission fluid be necessary.
Title: Re: Mixing Fluids in Power Assist Steering
Post by: Geoff on February 21, 2019, 09:27:19 AM
It mixes fine.
Title: Re: Mixing Fluids in Power Assist Steering
Post by: chessie4905 on February 21, 2019, 09:32:06 AM
Is the pump gear drive or pulley/belt? Leak at gear seal into engine?
Title: Re: Mixing Fluids in Power Assist Steering
Post by: Lin on February 21, 2019, 04:47:25 PM
It is gear driven.  I guess that would be another reason to switch to oil.
Title: Re: Mixing Fluids in Power Assist Steering
Post by: TomC on February 22, 2019, 09:37:35 AM
I use 15W-40 in my Sheppard power steering, and when it is cold it howls pretty good for about 5 minutes. If you use straight 30, it might be a real problem in the cold. Good Luck, TomC
Title: Re: Mixing Fluids in Power Assist Steering
Post by: chessie4905 on February 22, 2019, 11:51:45 AM
He mentioned power assist. I don't know if there is a difference in lube requirements.
Title: Re: Mixing Fluids in Power Assist Steering
Post by: buswarrior on February 22, 2019, 12:43:27 PM
It really doesn't matter what liquid soup you put in there, oil, transmission, mulit, single, mixed...

The fluid is there to be the muscle, not to perform anything fancier.

The pump just wants to push something.

Happy coaching!
Buswarrior
Title: Re: Mixing Fluids in Power Assist Steering
Post by: Dave5Cs on February 22, 2019, 02:32:30 PM
Power steering fluid = Wix filters SL 10012, Hydraulic oil- ATF Any of these are fine Clifford says the Ross book says. About 5 QTS. :)
Dexron ll
ATF type E or F        or             
Chevron 10/40
Chevron Torque 5 Fluid
Exxon H 32 Hydraulic
Fleet Line PSF
Ford spec M2
Mack EO-K2 engine oil
Mobil ATF 210
Mobil Super 10/40
Shell Rotella T 30w
Shell Rotella 15/40
Texaco 10/40
Texaco TL1833 power steering fluid
Union 10/40
Union 15/40
Unocal Guardol 15/40 there you go. that is the approved oils for your steering box from the TRW book
Title: Re: Mixing Fluids in Power Assist Steering
Post by: chessie4905 on February 22, 2019, 05:05:18 PM
Tom, if you replace your fluid with the synthetic equiv., it should have stable viscosity, hot or cold.