This answer is applicable for many BMWs in addition to the one listed below.
I have a 525i 1990. My steering has some free-play in it. After changing tie rod ends and drag link, I was still getting a bit of play so I put it on a lift and saw the movement coming from the steering box. What can I do?
Your 90 525i uses a recirculating-ball style steering box (vs. rack and pinion). These steering boxes can, and do, wear. There is a provision for minor bearing pre-load adjustment and this can often help with the wear induced play between the steering input and the output to the pitman arm and steering linkages.
The recirculation ball gearboxes are used on the following BMW chassis:
E12 (5-series through 81)
E28 (5-series 82-88)
E34 (5-series 89-96)
E39 V8 only (540i & M5 97-03)
E24 (6-series through 89)
E23 (7-series through 87)
E32 (7-series 88-94)
E38 (7-series 95-01)
E31 (8 series)
Before adjusting the gearbox bearing pre-load, inspect the steering shaft u-joint and rubber coupler for looseness or play (in the engine compartment, before the shaft connects to the gearbox). If there is wear or looseness, start by replacing the offending part (u-joint or coupler). If all is secure, proceed with the gearbox adjustments below.
If you do need to renew the u-joint assembly or the coupler, give us a call at 800-535-2002 and we can determine the proper application and part for you to order.
Adjust the steering gearbox bearing pre-load as follows:
* Raise the front wheels off the ground.
* Note the lock-nut with the slotted-head stud/screw in the center, on the top of the steering gearbox.
* Use a flat-blade screwdriver to hold the adjusting stud and loosen the lock-nut a couple turns.
* Rest your leg against the left tire and have a helper gently wiggle the steering wheel left and right, within the range of play. Take note how you can feel the tire/wheel begin to move as the steering wheel is moved back and forth within the range of play.
* Slowly rotate the adjustment stud/screw clockwise while feeling the amount of play. Take note of the point where the play is most reduced, prior to the adjuster getting tight. Continue turning the adjuster clockwise, from this point, until the adjuster is obviously tight and the steering feels tighter as well.
* Loosen the adjuster (counter-clockwise) until it is loose again (while moving the steering wheel back and forth). As you did in the step above, find the point where the adjuster starts to feel like it’s tightening, and the steering has most of the play eliminated, but does not feel tight. Back the adjust out (counter-clockwise) 1/8-th turn from the point where it begins to feel tight. Hold the adjuster with the screwdriver and tighten the lock-nut.
* Lower the car and go for a drive. Note if the steering feels heavy or does not want to return to center (after a turn) as it should. If this is the case, turn the adjuster another 1/8-th turn counter-clockwise and do another road test. Repeat as required.
You will likely not be able to eliminate 100% of the steering wheel free-play, but you should end up with less than you started with.