Results 1 to 13 of 13

Thread: ST185 power steering not keeping up

  1. #1
    Experience shows I'm no Chief Engine Builder Roundy's Avatar
    Join Date
    Sep 2005
    Location
    NSW
    Posts
    3,572

    Default ST185 power steering not keeping up

    Hi Guys,

    Had a bit of an issue in the motorkhana, which i have had before.

    Basically get to a slalom, and it seems i get no power assistance through there and the steering becomes amazingly heavy.

    It would seem that this sort of problem is not uncommon through a lot of cars, however i have seen nothing to really suggest how to fix it!

    Any suggestions would be much appreciated

    Cheers
    Nathan
    "If you try to fail, and succeed, which have you done?"
    My ST185 with 278awkw (2.2L is running...)
    1:08.08s @ Wakefield 1:37.29s @ Winton
    27.90s @ Esses Hillclimb

  2. #2
    Hopefully soon a 5S-GTE Chief Engine Builder MWP's Avatar
    Join Date
    Dec 2005
    Location
    South Australia
    Posts
    4,565

    Default Re: ST185 power steering not keeping up

    Sounds familiar... https://www.youtube.com/watch?v=4qjM9DY-iYc

    I tried giving the system a good flush, using different fluid and added a larger PS cooler radiator, none of it helped.
    I gather it was a problem with the valve assy in the rack, but never chased it up.

  3. #3
    Junior Member Backyard Mechanic
    Join Date
    Apr 2010
    Location
    Vic
    Posts
    231

    Default Re: ST185 power steering not keeping up

    strut tops often fill up with dirt replacing may help.

  4. #4
    I definitely ain't a Chief Engine Builder wagonist's Avatar
    Join Date
    Jul 2005
    Location
    NSW
    Posts
    3,275

    Default Re: ST185 power steering not keeping up

    I feel your pain
    It the reason the Dina doesn't get used for motorkhanas any more & why the Excel has remained non-power steer.

    Sainz, that isn't the problem. My 60000km old Caldina which hadn't been on dirt had exactly the same symptoms.

    I wondered about fitting a smaller pulley to the PS pump to see if the increased speed of the pump pushed more fluid through, and then maybe lightened up the steering. Might need a shorter belt then.

    I'd only use that for motorkhanas, as the extra force may blow seals if used too long like on the track (not to mention too light steering on the track would be counter-productive).
    But swapping a pulley & belt isn't too hard.

  5. #5
    Junior Member Domestic Engineer
    Join Date
    May 2011
    Location
    Queensland
    Posts
    689

    Default Re: ST185 power steering not keeping up

    Had any one tried a electric pump ie sw20?
    1990 ST185 Running stock Gen 3 power, 216awhp at 15psi. 13.6 second down the quarter

  6. #6
    I definitely ain't a Chief Engine Builder wagonist's Avatar
    Join Date
    Jul 2005
    Location
    NSW
    Posts
    3,275

    Default Re: ST185 power steering not keeping up

    I know some rally guys have installed an aftermarket kit onto older car, where an electric motor is attached to the steering column inside the cab.
    Saw it fitted to a 180B.
    I can try to track it down if you want. Rallying has similar issues with large & constant changes in steering angle.

  7. #7
    I definitely ain't a Chief Engine Builder wagonist's Avatar
    Join Date
    Jul 2005
    Location
    NSW
    Posts
    3,275

    Default Re: ST185 power steering not keeping up

    I came across this old article:

    http://www.autospeed.com.au/cms/A_11...popularArticle

    and I think I've got an idea of what's happening.

    In a motorkhana, both the steering and the throttle are subject to a huge & quick variation of their applications.

    Steering is done violently side to side, and the throttle is similarly fully depressed, then completely released, and then fully depressed again.

    As the power steering pump is driven by the engine, its load is governed by the revs. So if the throttle goes on & off, then so does the pump. As a hydraulic system with a viscous fluid inside, the fluid also gets subject to these loads by the pump, but due to the nature of the fluid (being viscous & having some momentum), any reactions to changes in the pump pressure would be delayed (but also damped).

    So basically, the only thing I can think of that may help is to replace the belt driven pump with a constant speed electric motor, so that there is a consistent pump pressure.

  8. #8
    Experience shows I'm no Chief Engine Builder Roundy's Avatar
    Join Date
    Sep 2005
    Location
    NSW
    Posts
    3,572

    Default Re: ST185 power steering not keeping up

    That article may be holding key to what i need to do.

    It is probably likely that the assistance is reduced with high RPM, which is where all the problems lie when you start sawing from left to right.

    Have seen some DSM people talking about disabling this feature.

    Otherwise guessing that electric pump is probably going to be the answer....damn
    "If you try to fail, and succeed, which have you done?"
    My ST185 with 278awkw (2.2L is running...)
    1:08.08s @ Wakefield 1:37.29s @ Winton
    27.90s @ Esses Hillclimb

  9. #9
    I definitely ain't a Chief Engine Builder wagonist's Avatar
    Join Date
    Jul 2005
    Location
    NSW
    Posts
    3,275

    Default Re: ST185 power steering not keeping up

    Hence the reason I suggested a smaller pully on the pump, so its still overspeeding the pump at higher revs, thus giving more assistance. Or is it that it needs a bigger pulley so that the pump thinks its at a lower rev point...

    The first Generation Subaru Legacy GT turbo (Oz got the facelighted, but downspec'd version with the Liberty RS Turbo) had electronically variable power steering. There was a button on the dash which turned it to/from "sports" mode.
    I owned a JDM version of the facelight 1st Generation (ie an import) where this was changed to a computer controlled function instead. I remember it losing the plot when I'd go to reverse park in a small town after spirited drive on a windy road (eg Singleton after coming up the Putty Rd), and it'd just have no idea and be overly heavy. But unlike the steering racks fitted to the Oz models, there was some kind of sensor fitted to the side of the steering column input.

  10. #10
    Hopefully soon a 5S-GTE Chief Engine Builder MWP's Avatar
    Join Date
    Dec 2005
    Location
    South Australia
    Posts
    4,565

    Default Re: ST185 power steering not keeping up

    Quote Originally Posted by wagonist View Post
    As the power steering pump is driven by the engine, its load is governed by the revs. So if the throttle goes on & off, then so does the pump. As a hydraulic system with a viscous fluid inside, the fluid also gets subject to these loads by the pump, but due to the nature of the fluid (being viscous & having some momentum), any reactions to changes in the pump pressure would be delayed (but also damped).
    I can see where you are going... but i dont think its the case.
    These are road cars that are made to have light steering in parking lots, so the pump will be large enough to maintain pressure at low rpms / idle.
    The PS pump bypass valve will almost always open to some degree to maintain line pressure.
    I would be surprised if that smallish bypass valve cant keep up with rapid steering movement & RPM changes (not really that rapid).

    Im starting to think that the PS pump bypass valve may be at fault.
    Maybe when old they gunk up and become prone to being stuck open when the oil is hot?

  11. #11
    I definitely ain't a Chief Engine Builder wagonist's Avatar
    Join Date
    Jul 2005
    Location
    NSW
    Posts
    3,275

    Default Re: ST185 power steering not keeping up

    The ideal is to have pump speed dependant on road speed, but this is difficult (although some Super Tourers of the 90s had stuff like P/S pump & alternator running off Cam pulleys & even CV joints) so manufacturers make it dependant on engine speed.
    Most parking happens at or near idle, when revs are low.
    We're trying to get assistance at higher revs than this, plus overcome that the racks is being violently moved from one side to the other.
    the hydraulics simply can't keep up in stock form.
    I bet I could jump into a brasnd new WRX and get this syptom to occur at a motorkhana, so I think it's doubtful age and residue build up would be the cause.

  12. #12
    Hopefully soon a 5S-GTE Chief Engine Builder MWP's Avatar
    Join Date
    Dec 2005
    Location
    South Australia
    Posts
    4,565

    Default Re: ST185 power steering not keeping up

    Quote Originally Posted by wagonist View Post
    We're trying to get assistance at higher revs than this, plus overcome that the racks is being violently moved from one side to the other.
    the hydraulics simply can't keep up in stock form.
    What cant keep up exactly?
    Its a pretty simple system...

  13. #13
    I definitely ain't a Chief Engine Builder wagonist's Avatar
    Join Date
    Jul 2005
    Location
    NSW
    Posts
    3,275

    Default Re: ST185 power steering not keeping up


Similar Threads

  1. Replies: 3
    Last Post: 31-07-2006, 09:15 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •