Steering rack rattle
 

I have had a rattle on my right driver's side steering/suspension for a while now and it has progressively got worse over a couple of years from barely perceptable to now what I consider terrible. Mileage is 280,000.

I have replaced the upper arms again, ARB links again. All were pretty much perfect anyway.

A few days ago, after changing the right driver's tie rod (which appeared fine) bliss. Perfectly quiet, no more ratlle over bumps.

The steering was alightly offset, so I adjusted this the next day after work and then the next day was to test on the way to work - the rattle had returned and got worse over the course of the journey until back to normal.

It would seem this rattle was surpressed by the steering being slightly offset (I'm talking 1cm at the steering wheel rim) or perhaps the fact I cleaned and greased the rack teeth inside the bellow. Maybe the new grease gave temporary relief and has now been hot and squeezed out during steering.

I am not sure how to proceed. The rack bar (with the teeth) hidden in the tie-rod bellow was quite dryjust a film of browny/red sticky grease. I just cleaned with brake cleaner and put some ceramic brake grease on it. Maybe I should get some proper thick rack grease and lather it? Also I asume these rack teeth will not be present within the bellow on the passenger side as there is no pinion from the steering column?

Has anyone here adjusted the steering preload on the D3? Looks really difficult to reach. Is it the nut I have arrowed on the pic?
What does this actually do inside the rack?

I don't experience any steering slop or knocking sensation through the steering wheel, just I can hear a 1-2mm metal on metal type thrashing back and forth rattle over small bumps such as brown surfaces, big cats eyes, drop kerbs or drain covers. It also happens dead ahead or when turning left but not when turning right and only ever when the right driver's wheel goes over the bump.

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Found the instructions - so will give this a shot, also ordered the proper grease £15 for 10g from VW or £16 for 100g from BMW!
It's said to be the same ZF stuff so I went with BMW.

BMW Steering Rack Lubricating Grease 100g FB-1 2208093 83232208093
Steering Rack Grease 10g > Volkswagen ProductPart Code: G052168A1

I recently adjusted the preload on my D3 whilst changing the track rod ends. The symptoms are more of a clunk when turning the wheel.

Its not too difficult a job once you get the spanner on, 16mm if I remember correctly.

If you take the rear wheel liner off and pull the rubber shield forward (unless you undo the TRE you cant remove it) you can just see the bolt along the rack. The heatshield may get in the way a little, but can be safely pushed down to give access. You can turn the bolt about 1/6 rotation at each go. I think I did about 1.5 turns (on 230k car).

I initially tried to gauge the tightness on the jack stands, but could get a feel for how tight the steering was and over did it, but you can actually reach the bolt even with the wheels on, so was able to loosen it up while I drove around.

I did it on A6 but on D2 I could not get the bolt turning. I also first over-did it on A6. I did it by feel with the rack near mid position but as the most of the time rack spends near middle position it's more worn in the middle. When it felt fine in middle it was too tight on more lock so had to loosen it a bit.

Thanks for the advice everyone. I can now make it clunk by shaking the steering around the centre point. I think the main cause is cleaning off the grease and replacing it with a much softer grease. I have already checked that everything is tight.
I didn’t know this but grease has a thickness rating 1-6. 1 is semi fluid and 6 come as a brick like fudge. I have ordered some 3 and 4 in case the proper grease is not thick enough to cushion it after adjusting. I expect I have most of the wear on centre and so adjusting will be between two conflicting compromises of binding off centre and backlash on centre. The grease rating is called NLGI. Sometimes the name of the product will have this rating number e.g. EP2 or NG3.
The racks are £200-400 remanufactured which is not bad but the task of fitting looks terrible.
Maybe this greasing should be a maintenance item say every 100,000 miles to help reduce wear.

I had this same issue with the rack in Neil's D2 - very worn around the centre but fine at the edges. If it was adjusted enough to take out the play in the centre it wouldn't move more than a few inches in each direction. Loose enough to get lock to lock and it was scary in a straight line. We enquired about a re-con rack but all they do is replace the seals for the D2, and don't replace the actual rack and pinion so if your return rack is toast you lose your deposit. We just fitted a used one instead.

Thanks everyone, with your help I was able to fix the issue.
I removed the rear wheelarch liner, plastic protector for driveshaft and rubber insulator that the inner tie-rod passes through. Removed the tie-rod assembly again and steered left to send the rack-bar out of the rack.
I then cleaned it really well and applied liberally Millers DELTA 3EP as this seemed most like the original (The BMW stuff was very soft yellow grease)

Here are the photos but they are all rotated 90˚ CCW (why does this happen on this forum, I have also resaved and reuploaded them with the same result?), you can see the spanner on the nut on the 'movie'. The nut turned easily and in a few increments with test drives, I did it a full turn when the rack was dry and then greased it up once satisfied - there is no binding off-centre, in fact it feels no different than before. One day I will do the plain bar on the passenger side just to protect it.


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