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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

    Background
    Several times over the many years of ownership, I've lost steering assist.
    The fastest, surest way to determine if it is the steering box that is messing up is to swap it out for another unit, preferably known to be good.
    Here we have my original box along with a salvage unit that I picked up for around $400. Both have been in and out so many times, I got fluent in the procedure.



    This write up is my claim to the most efficient path for accomplishing a pull of the steering box.
    It may or may not have correlation to shop manual methods. I wouldn't know, typical man, never read instructions.

    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.
    The 850 and other years will differ slightly in steering box and hydraulic lines.
    Very early years will not have the X-frame.
    Pics will typically show work done on the left side components, and it is understood that both sides require the procedure.

    Two major steps, in sequence
    The top level strategy is to sequence actions to maintain order and minimize total work required.
    To that end we will be first removing the X-frame away from the vehicle.







    Almost the sole reason for the X-frame removal is due to an unfortunate mechanical overlap onto the engine cradle.
    Only then do we support the engine and detach the engine cradle from the chassis, and lower it for access to the steering box.
    If we could magically make the engine invisible,
    here is how the steering box would look sitting on the cradle.


    Tools
    Floor jack
    Jacking / lifting pad
    2 jack stands for vehicle
    1 jack stand for engine support
    2 wheel dollies, optional
    Balljoint popper, for steering linkage
    22 mm socket, for ...
    · Banjo bolt at steering box output port
    · X-frame to chassis
    · Upper/rear control arm to X-frame
    19 mm socket, for...
    · Lower/front control arm to engine cradle.
    · Steering box to engine cradle
    17 mm socket, for...
    · Forward bolts, sub-frame to chassis
    · Nut, engine mount
    16mm socket, for sway bar link
    15mm socket
    13 mm socket, for
    · Nut, engine mount
    10mm socket, for...
    · Shields
    15" of ratchet extension, to reach banjo bolt on steering box output port
    8mm allen, for drain plug at the vane pump
    Bucket, perhaps 2 quart / liter
    Drip pan
    Misc open-end wrenches
    Philips screwdriver, for sheet metal screws attaching engine screen
    Hammer and long metal rod, for protection in rough neighborhoods.

    Jack vehicle
    This to gain access on this low vehicle and because we will be removing control arms making the front suspension incapable of supporting the front end.
    Although the wheels can be left on, it is suggested that they come off, to eliminate the weight as the struts are pushed around.
    Shown below, a lifting pad and jack stand.
    A good policy is to position the loose wheel under the vehicle as a failsafe.



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




    X-Frame: Why remove?
    This removal action is required because the X-frame overlaps the engine cradle, which is what we ultimately want to remove.
    For the convenience of a clean work space, remove the X-frame and start in on the engine cradle before opening any lines.

    Sway bar can be left on the X-frame.

    We prep for unbolting the X-frame from the chassis by first disconnecting...
    · sway bar link
    · upper / rear control arm
    · shield



    X-Frame: Sway bar links
    Immobilize the ball joint with an 17mm open end, although 5/8 will do.
    On the nut, that's a 16mm socket.
    Right side shown.



    X-frame: Upper/rear link
    Unbolt at the X-frame rather than at wheel knuckle where we would have to pop some stubborn ball joints.



    X-frame: Shields
    Attached at the rear of the X-frame, both sides.
    10mm.



    X-frame: Chassis bolts
    Support X-frame, preferably with a floor jack, to lower and wheel away.
    Alternatively as shown below, place jackstands to prevent injury while unbolting. With sway bar, if weighs about 25 lbs.
    Fyi, when re-installing, and knowing the weight, I was able to bench press it into position and get bolts started.

    Four bolts each side...
    · Forward bolt at engine cradle. Really long. 17mm socket


    · Middle, thick, probably an M14, appears to be same as used for the upper rear control arm. 22mm head.


    · At sway bar bushing, short, 15mm socket.


    · Rear, relatively short, 15mm socket.


    X-Frame bolt survey, unfortunately disorganized and not complete. Each side...



    Engine cradle: Why remove?
    AKA sub-frame, this piece supports the steering box, bolted to the top surface and inaccessible without the disconnection and lowering of the frame.
    Unfortunately, the engine is also bolted to this cross member and therefore must be supported independently while the frame is detached.

    It is not required to detach the forward control arm (aka lower arm), as the engine cradle can to lowered and lifted while the arm is attached.
    However, its not a mistake to do so.
    19mm wrench and socket

    Engine cradle: Shields
    Bolts, three places each side. 10mm head all.
    · At chassis. Wide combo washer. 10mm head



    · At engine cradle, hidden by black cap.12 mm length, 10mm head
    Carefully (!) loosen and lower with the socket wrench! Don't lose it inside the cradle.


    · At rear of X-frame. See X-frame: shield for pic.
    The shield on the right side of the vehicle can be left attached to chassis.


    Engine cradle: Drain hydraulic fluid
    This step has deliberately delayed until most other ops were accomplished, because once lines are opened,
    they tend to drip uncontrolled, requiring trays and / or constant wipe-ups that interfer with wenching.

    Fluid drain at pump, expect about 2/3 liter for this single vane app. Takes 8mm allen.
    Inspect seal.



    Engine cradle: Disconnect hydraulic lines
    Pressure line. 17mm wrench. See footnotes for an alt wrench.


    View looking down along the pressure line.
    We are after that banjo bolt on the low pressure line, aka the box's output port.


    22mm socket on 15" minimum 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.


    2nd Alert! There are two crush washers associated with the banjo bolt.
    Replace the bolt so as to prevent debris into the port.


    Engine cradle: Engine support, chassis bolts, engine bolts, intermediate lowering


    Alt method


    Engine mounts, conical nuts
    17mm and 13mm socket

    Cradle bolts to chassis
    2 bolts remaining each side. 17mm heads



    Lower the cradle approximately and inch and half, to allow detachment of steering u-joint.

    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.



    View of long rod unsticking the engine cradle.


    Engine cradle: Steering box connections.
    Three...
    · Wire harness to the variable assist valve, aka Servotronic.
    · Steering column U-joint on input
    · Pitman arm on output

    Servotronic harness connection
    (If your steering box is original and has the servotronic function)
    Squeeze the wire lock, and pull lightly.


    Column U-joint
    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 feature.
    DO NOT hammer the yoke directly as it is aluminum and will deform.



    Pitman arm to cross linkage using a ball-joint popper. Very little effort required.



    Continue lowering the cradel, gaining access to the box mounting bolts.

    Engine cradle: Steering box detach


    Two bolts plus associated washers, bushing and nut.







    Footnotes
    1) During install, 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 is not getting 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, 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) During assembly, follow the factory manual for bolt torque values.
    Last edited by Hyper; 02-07-2021 at 12:35 AM. Reason: Was in sad condition, now much improved

  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.

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