Hi all.
If you ever experienced a failure of the steering gearbox; how did the steering behave ? Do you know what failed inside the box ? Is there some sort of hydraulic motor inside ?

 

The D2 has an old school recirculating ball steering box, extremely rare for them to fail. Occasionally you'll see one with a seal failure. They do however develop some slack over time and you'll need to remove the slack using the adjustment screw on the top of the box

 

What causes the slack? I wheel often and my steering is quite loose, to the point where 15 degrees right or left of play before the steering actually moves.

 

The slack is typically caused by normal wear and tear. My experience with adjusting steering boxes is from my 2A, but I think the principle is the same. You can adjust the slack out, but be aware that most of the wear will be near the centre of travel. You can adjust a steering box to spec with the wheel centred and then find it is too tight with the wheel turned. You can probably find a happy medium, unless the box is very badly worn.

 

Thanks.
Is there a steering box failure mode where power steering assist goes totally absent ? (Not caused by the pump) Like something jammed in it or broken, or a stuck valve, or... ? -No leaks related.

Is this the flow?
Reservoir ----> pump ----> cooling pipe -----> gearbox -----> reservoir

 

Do you have flow (check the reservoir return)? Maybe pressure relief valve stuck open (in pump) but never heard of that. Possibly filter assembly in tank plugged causing pump to cavitate (again, flow). As far as box adjustment, you just loosen the locknut and tighten the screw until you feel a little resistance, not more. Then tighten locknut.

 

Make sure to check your steering U-Joint as well:
People don't really talk about this, at least from what I've read.