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Thread: HowTo->Pull the steering box

  1. #1
    Join Date
    Jun 2010
    Location
    Hyperworld
    Posts
    888
    My Cars
    '97 840CI

    HowTo->Pull the steering box

    This content obsolete as of Feb 5 2021. Link to updated content.

    Background

    Following some repairs on the hydraulic lines, I discovered my steering and brake assist was gone.
    DejaVu way back to my work diagnosing hydraulics.
    We know that if the steering box passes high volume, then it pulls the entire system down the volume-pressure curve, eventually taking out the brake assist also.
    The fastest, surest way to determine if it IS the steering box that is messing up is to swap it out for a know good unit.


    This writeup is my most recent, cleanest path for accomplishing a pull of the steering box.
    This updates and replaces the "pull" preamble previously found in the thread HowTo->Overhaul a ZF steering box.
    Here, more comprehensive with better pics.

    My estimate would be 2-3 hours for a first time novice, 1.5 hours for an organized talented owner, and no more than 45 minutes for a professional tech on game day.
    Same numbers again for putting the box back.

    The vehicle shown herein is a 1997 840, with X-frame and servotronic.
    The 850 and other years may differ slightly in steering box and hydraulic lines.
    Very early years will not have the X-frame.

    Tools, assuming no commercial garage lift
    Floor jack
    Lifting pad
    2 jack stands for vehicle
    1 jack stand for engine support
    2 wheel dollies, optional
    Balljoint popper, for the steering linkage
    22 mm socket, for banjo at box,
    15" of ratchet extension
    8mm allen, at vane pump
    Bucket, perhaps 2 quart / liter
    Drip pan
    Misc flat and philips screwdrivers
    Hammer and long metal rod, for protection in rough neighborhoods
    Misc open-end wrenches
    Misc close-end wrenches

    Jack vehicle
    This to gain access on this low clearance vehicle and because we will be removing control arms making the front suspension incapable of supporting the front end.
    Although the front wheels can be left on, and that is how it is shown herein, it is suggested that they come off, to eliminate the weight as the struts get pushed around.
    Not shown, jackstands. You will use them.


    Rock / wind screen
    4 screws, probably 4.2 aka #8
    Inspect body nuts



    Fluid drain at pump
    Takes 8mm allen. And a bucket.



    Inspect seal



    Pressure line at regulator
    Takes 17mm open-end.



    Banjo bolt, cooler line at steering box
    Takes 22mm socket and 15" minimum of extension.



    You didn't forget the pan, did you?
    Shop tip: Whenever opening ANY connection, assume fluids will come out.
    Same applies when you even slightly move an open line.
    Same applies when you overturn the steering box.




    Sway bar links
    Immobilize using a 17mm open end, or 5/8 as shown
    That might be (?) a 15mm socket



    X-frame, except on very early model years
    Support X-frame, jackstand option shown. With sway bar, if weighs about 25 lbs.
    On the way back in, and knowing the weight, I was able to bench press it into position and get bolts started.



    Bolts, each side...
    - 2, relatively short, like 15mm
    - 1, really long
    - 1, relatively thick, probably M14

    Hardware survey, disorganized and not complete. Each side...


    Shield(s). Each side.
    Do not disassemble halves.
    Left side shield has a notch, when the servotronic is present.
    3 fasteners each side @...
    - Body, with relatively large washer.
    - Engine cradle, under cap. Relatively long, like 12mm
    - X-frame. Relatively short, like 8mm.



    Column yoke
    Remove the yoke bolt. 13mm wrenches.
    It is not sufficient to merely loosen as there is an interference notch on the shaft.


    Slide the yoke off the steering box input shaft.
    It is not necessary to make any arrangements in the cabin.
    DO NOT pry between the yoke end and the delicate plastic pointer on the box.
    Here we are using a 1-1/2 in wide crow bar wedged between the yoke's upper U and a set of bolts on the steering box.
    It may help to LIGHTLY tap a thick, flat screwdriver into the clamp gap.
    DO NOT hammer the yoke directly as it is aluminum and will deform.


    Engine mounts, engine support
    Disconnect mounts from engine cradle by removing 2 nuts each side.
    Support the engine. Here we have lifted the engine perhaps a half inch, then set it back down on a jackstand with a wood board across the entire front edge of the steel oil pan.
    This support will see approximately half the engine weight, about 220 lbs.


    Engine cradle, aka subframe
    Remove bolt from control arm at the engine cradle.
    The control arm can swing out of the way to the rear.
    Engine cradle fasteners...
    - Long bolt at rear but should have been removed already with X-frame
    - 2 relatively short, up front




    Dang, engine cradle is stuck
    A dowel locates the engine cradle to the vehicle chassis.
    A heavy hammer on a long rod got it unstuck.




    Lower the engine cradle, balanced on the floor jack.



    Steering arm
    Common balljoint tool. Requires very little effort.



    Unbolt box from cradle. Two bolts plus associated washers and nut.



    Footnotes
    1) During assembly, follow the factory manual for bolt torque values.

    2)
    Quote Originally Posted by toomanyparts View Post
    ... suggest 17mm flare wrench for the regulator lines as they are easy to mangle if not delicate in technique...


    3) As you are returning the steering box into place, manage the pressure line so that it doesn't get jammed up into the engine heads.


    4) Line up the column yoke with the pointer on the box so that the steering wheel in the cabin is clocked properly.


    5) The suspension must be fully compressed when tightening the control arm bushings.
    Since we still require access to the wrenching zone in this low clearance vehicle, this means the tire patch must be elevated.
    Here I've gotten paranoid about suspension deflection and binding, and so have used dollies to give the tire patch freedom of movement.


    6) This spot marks the X, except on very early years.
    Oooooh, is that an LED strip, used as shop light?
    Last edited by Hyper; 02-07-2021 at 12:55 AM. Reason: Content obsoleted

  2. #2
    Join Date
    Mar 2011
    Location
    Liberal Loontown, CA
    Posts
    2,658
    My Cars
    Cool Volvo, Ugly BMW
    Amazing documentation as usual. Only note I would make is that you might suggest 17mm flare wrench for the regulator lines as they are easy to mangle if not delicate in technique.

    Very helpful for future reference. Thank you.
    What "thumbs up" really means




  3. #3
    Join Date
    Jun 2010
    Location
    Hyperworld
    Posts
    888
    My Cars
    '97 840CI
    Quote Originally Posted by toomanyparts View Post
    ...you might suggest 17mm flare wrench...
    Or you might, as now quoted in the footnote section.

  4. #4
    Join Date
    Oct 2016
    Location
    Shoreview MN
    Posts
    977
    My Cars
    Had a 1991 BMW 850
    Installed the Subframe, What a PIA.


    Plan A was to bolt Steering Box to Subframe because its mounting bolt is exceptionaly hard to get to once mounted. This did not work because subframe is awkward and with the heavy steering box extremely unbalanced. Maybe with a lift or two guys.


    Plan B Put steering box on a Jack and raise it up and then hang it by the hose and then insert the splined end into the steering shackle. Fail because the shackle moves into the steering column and there is nothing to push against. Spent way to much time on this.


    Plan C With Steering box hanging, I hooked everything else back up, Put the Motor Mounts back in ( Make sure they are correctly aligned but loose). Hang the Subframe on the Long bolt on the passenger side. Support other end with a Jack. Put the PIA bolt into the steering Box and tighten. Now it is just a matter of getting the motor mounts to align top and bottom and getting the dowels in the back to align, tighten everything up. I used new bolts as my original ones were heavily corroded. And then go back and put steering shackle onto the steering box. I am going to try to pry from underneath, there is a nice spot right next to the exhaust that should work with a block of wood.

  5. #5
    Join Date
    Jun 2010
    Location
    Hyperworld
    Posts
    888
    My Cars
    '97 840CI

    Content updated

    Just recently I had to swap my steering box again, and needed to reference this thread to remember How-To.
    Trying to follow my own instructions, that's when I discovered the content was incomplete or out of sequence, and in general needed some serious work because it was fairly useless if you weren't already an experienced wrencher.
    So FYI over in the subforum "E31 Common Problems and DIY fixes" I have updated that content over there with much better text and much more, detailed pics.
    For instance I discuss why the sequencing, alternative options, what to watch out for, and tool size.
    The original, crappy content is retained in this thread above.

    *** ed ***
    For example, I came across this gem in my library, and its now included.
    The engine has been cloaked, revealing the steering box "in situ".


    Example #2:
    The original content instructs the journeyman to drop a socket extension down in there to disconnect the return line.
    The updated content alerts the apprentice that there are crush washers involved, suggest that the banjo bolt be re-installed to prevent foreign objects and to capture those crush washers as a reminder for later on.
    Last edited by Hyper; 02-07-2021 at 11:37 AM.

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