Fixes - Steering

Remove steering wheel

Removing the Steering Wheel
Article by: Bill Rickard
This article will show you the process I used to remove the steering wheel in my effort to change out the dash bulbs.
1. First you disconnect the negative battery cable. This is critical.
Make sure you have the code for the radio before doing this!

2. Wait 30 minutes for the airbag to discharge (on cars older than 9/93), then remove the 2 philips screws that hold the steering column cover on the bottom.

Make sure you disconnected the battery.
Then you remove the bottom cover on the steering column. When that's removed you will see an orange connector.
That's the airbag connector. Squeeze the clip ends and separate the connector.

Remove the end that goes to the steering wheel from the post its fastened to.

Using a T27 torx socket or driver, then remove the 2 screws on the back of the steering wheel that hold the airbag in place.

Next you carefully lift the airbag assembly off of the wheel and disconnect the plug on the back. It comes straight out to remove. Then set the airbag aside in a place where it won't get disturbed or damaged.

Then you remove the 22mm self-locking nut that holds the steering wheel on. This nut is to be replaced as it's only intended to be used once. The torque when reinstalling is 59 ft.lbs.  Once that nut is removed, mark the steering shaft and the wheel with a marker. A line across both so you can put the wheel back on in the same place. Put the key in the ignition next and turn to the run position. The wheel will then lift off.

Once the wheel is out of the way you remove the 2 philips screw that are in the top of the instrument cluster and carefully pull the cluster out far enough to remove the wiring connectors on the back. There are little levers you raise to release the connectors.

Next lay the instrument cluster down on a towel or mat to protect the face and on the back is most of the bulbs. To get to the 3 that provide the main illumination at night you have to turn the 2 latches counterclockwise 1/4 turn and swing the back panel up. The rest of the bulbs are on the back panel.
This car was a 1990 525i, it had:

Qty: 6 - 1.5 watt bulbs

Qty: 3- 3 watt bulbs

Qty: 13- 1.2 watt bulbs
The 1.5 watt bulbs I had to get from BMW, all the rest were available through aftermarket sources.  The 1.5s provide the lighting for the gear indicator on an automatic, the check instrument display, the service indicator and the odometer. These are the ones that are on most of the time.
The 1.2s I wasn't as concerned about changing since they aren't on nearly as much. These are all the warning lights, turn signals, bright indicator etc.
I changed the 3 watt bulbs since they light the gauges at night.

I think that about covers it all. Then put it back together in the reverse.

Make sure you don't hook up the battery until the very last.
Turn the key off after the steering wheel is installed, then reconnect the battery. Otherwise it will trigger an SRS code and have to be reset. One other note, On most of the other e34 models the battery is under the rear seat. To gain access just pull up really hard on the front bottom of the seat. While your in there you can look at the bottom of the steering wheel where the copper paste is and spread it around if you have a squeaking problem. A few other notes as well. Some models will have a nut holding the steering wheel on, some will have a bolt instead. You don't abolutely have to replace the bolt or nut, you can just use loctite on it if needed.  Also some airbags will take a t27 torx, some will take a t29 torx.

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Repair of servotronic unit

From Yuriy:
About 3 months ago, my servotronic started to fail: intermittent shutoffs and then I was stuck with minimum assist until yesterday.
Reflowing the solder, as was expected, didn't do any good, so I decided to work on the circuit itself. Sure enough, after desoldering the two transistors, Emitter-Collector link in both of them either had a ~5MOhm resistance or even was positive on the diode test. In other words, both were BLOWN, BURNED, BUSTED!
I've managed to get the P/N from them and ordered replacements from digi-key.com. Soldered them in and VOILA! :))

• George Mann used an 18 ohm fixed resistor (wire wound high capacity type) to bypass his servotronic -- 18 ohms gave him reasonable balance between highway and city driving feel.

Part #'s shown in the photo  -- but check your unit before repairing it

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Cleaning/replacing the servotronic hydraulic unit

Here the story. My wife complained that sometimes the servotronic was not working and steering was very hard.
Unfortunately I could not re-test such fault.
Yesterday when we were working on the cars I told the guys the story and Take and Terashima said it could be the tiny metal strainer which could be clogged partly by micro parts from seals, O-rings etc in the complete hydraulic system.
I had never noticed this part before. I had already replaced the servotronic control module behind the speaker driver side, no change.
That strainer is located at the bottom of the steering gear where the Servotronic Control Unit; Torque Converter for Servotronic steering box is located.
So we jacked the car up on the left front side, removed the front wheel and then had access to the servotronic control torque converter unit.

This shows the general location of the unit - indicated by the arrow.

This shows the unit with screen and the bolts.

Remove the 2 long bolts (special bit is needed) shown in that pic, pull out the torque converter, make sure you do not lose the small O-Ring. Pentosin will drain out. That small filter was partly clogged with tiny/micro rubber parts and that caused the power steering to malfunction sometimes, as there is the flow into the TC for servotronic, also there is a tiny hole on the TC.

This shows the actual part.

We cleaned the filter, no more trouble since then. see also here

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