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Steering shaft upper bearing

Posted: Thu Nov 10, 2016 11:10 am
by AndrewSlater
I have been cleaning up my steering column and checking the state of the bearings on my '74 911.
The column felt quite notchy so I have bought a replacement bottom bearing and was looking into the top one.

I notice that the replacement ones seem to all have the serrated plastic inner bush.
Mine has no plastic bush just the metal serrated bush.

Now that I have cleaned up the bearing and regreased it the bearing itself is fine.
Can I refit it with the metal bush or am I missing the plastic insert?
I realise a portion of the bush lip is missing as it broke off when I disassembled the column.

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As always any help is really appreciated.
Andrew

Re: Steering shaft upper bearing

Posted: Thu Nov 10, 2016 1:08 pm
by fetuhoe
Someone has knocked in a bearing tolerance ring of the type used to hold on the gear knob and then knocked the end over.

There is a sleeve on the 928 that is commonly used to do this job as they knock in without dismantling the column.

I think if you have it this far apart fitting the new correct bearing is the best idea.

Re: Steering shaft upper bearing

Posted: Thu Nov 10, 2016 1:43 pm
by AndrewSlater
Thanks for the input Chris.

I hadn't considered that the metal bush wasn't original.
Isn't the metal bush the one shown on the PET diagram 111053535D 'guide bush' - item 14?
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My confusion was whether the original bearings had no plastic inner and that the metal bush was fitted, and that the later ones have the plastic bush and that the metal bush is not required.

I see people using the metal bush when their plastic inner has disintegrated, but don't see any using the metal bush with the plastic inner.
I was half guessing that the early 74 cars have a plain bearing and use the metal bush, and that if I bought a new bearing it would have the plastic inner fitted which I suspect is a later bearing.

I'm still confused :roll:

Re: Steering shaft upper bearing

Posted: Sat Nov 12, 2016 9:30 am
by fetuhoe
Interesting.

I have never seen the tolerance ring type steering shaft but I have seen them with a smooth sleeve so they have probably been replaced.

I think that the worn sleeve you have has been superseded by 928.347.739.02 which is a smooth sleeve.

The bearing with the plastic sleeve was used from 1978 onwards and is, I think, a direct replacement for both the bearing and the sleeve.

When the plastic inner of the later bearing disintegrates the 928 steel sleeve is often 'tapped' into place to eliminate the clearance.

Sorry for the confusion.