Steering lock puzzle

Hi guys. I'm back fixing our cars myself, after a couple of decades of leaving them to the main dealers. It's nice to be back! On my Mk1 Octavia, which I've had for just over nine years, I've just changed the sump, subframe, and lower control arms (using new nuts and bolts) after an unfortunate encounter with some exposed ironworks during some recent roadworks. Now, once again, the front suspension is silent and the handling is great.

Next I'm trying to solve a steering problem. I recently noticed that the front wheels were turning too far to the right to the extent that the OS tyre was scrubbing against the bodywork. I noticed this after the ironworks incident and before I did the above repairs. However, I suspect it has been there since I bought the car, or at least since 2010 when the dealer change the OS tie rod and then did a four-wheel alignment.

I found that when the steering wheel was locked in the straight ahead position, the rack was 3.5 mm to the right of centre. I measured this by removing both steering gaiters and measuring the distance from the rack to the tie rod, as specified in the online Skoda manual (http://workshop-manuals.com/skoda/octavia-mk1/chassis/steering/summary_of_components_of_power-steering_gear_lhd_vehicles/repairing_power-steering_gear_%28zf%29/). With the rack centred, both distances should be 30.5 mm. On mine, the NS was around 27.0 mm, and the OS around 34.0 mm.

The tie rods were adjusted to compensate. In particular, the OS tie rod was set 3.5 mm too short. With the steering wheel nearly fully clockwise, this caused the OS wheel to turn an additional 5 degrees (approx) to the right, which was sufficient to cause the OS tyre to scrub the bodywork. The maximum angle should be 40 degrees. Mine was around 45.

In an attempt to correct this, I first disconnected the clamp that connects the steering shaft to the splined shaft on the rack with the intention of rotating it a spline or two. However, I found that it can only go on one way thanks to a flat on one side and a bolt on the other.

Next I removed the steering wheel (taking the usual airbag precautions) and rotated it around 20 degrees to the left so that from the straight ahead position it turns the same amount anticlockwise and clockwise (almost exactly 1.5 turns each way). I then set the tracking.

That's how it is now. The car drives great. With the steering wheel in the straight ahead position the car drives straight ahead, and the steering wheel can be turned from end to end without either tyre touching the bodywork and with the same tyre to bodywork clearance for each tyre.

The problem is that the steering lock, i.e. the lock that engages when the ignition key is removed, acts when the steering wheel is around 20 degrees to the left rather than when it is in the straight ahead position. That slightly concerns me. In the one-in-a-million chance that the steering lock engages whilst I'm driving, I'd prefer it to lock in the straight ahead position rather than off to the left.

I dismantled the cowling and removed the stalks looking for a way to set / reset the position at which the steering lock acts but couldn't find one.

I also looked at the near identical steering column in a 2008 Skoda Fabia. With the steering wheel in the straight ahead position, the clamp on the steering rack shaft was in the same position as mine *after* I rotated the steering wheel to the left. This suggests that the fault is inside the car and not in the steering rack. Up to that point I wondered whether the steering rack pinion inside the rack was one tooth out.

What I want to know is what has changed since the car was new to cause this problem. Was the steering wheel turned clockwise 20 degrees at some time in the past, either before I bought the car or in 2010 when the tie rod and four wheel alignment was done? If so, whoever did it must also have reset the steering lock position because the steering wheel locked in the straight ahead position after it was done. Alternatively, is there some point between the steering lock and the rack shaft clamp where the 20 degree offset was introduced and where I can put it back now?

Finally, Simeon85 wrote on 1st Dec 2015 (http://www.briskoda.net/forums/topic/378138-steering-lock-stop-not-stopping-the-lock/?hl=%2Bsteering#entry4457085):
 

 

It sounds to me like the straight ahead position on the steering wheel is simply not at the center position of the rack. Happens all the time on old golfs, on my mates one the garage set it so he has half a turn more lock right and the tyre has scrubbed all the underseal off the inner arch where it touches. Take it to a wheel alignment centre, have them take the steering wheel off the splines and using the laser equipment they can actually center 'lock to lock' before setting toe etc. Then put the wheel back on in the straight ahead position and job done.

That's essentially what I've done, but it results in the offet steering lock problem.

Can the steering lock position be reset? Have I missed something or got something wrong?

Apologies for such a long first post!

Cheers,

JB.

Edited 15 December, 201510 yr by JB2015