Lotus Elan

Steering rack stripdown

PostPost by: William2 » Thu Mar 27, 2014 4:59 pm

On stripping down my S4 steering rack I would like to seek advice on a couple of parts. When I removed the large hex nut (the one with the grease point) on top of the rack it had 3 shim washers followed by the spring and then a spring washer between the spring and the nylon plunger part seated in the rack. I note that the Lotus manual does not show any spring washer. Should this be fitted or not?
The other parts query I have is where the shim washer(s) should fit on the upper part of the pinion shaft. Should they be between the lower collar and the main collar?
I have attached a photo of these particular parts.
Attachments
Shim 001.JPG and
William2
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PostPost by: andyelan » Thu Mar 27, 2014 7:24 pm

Hi William

The parts you show in your photo should be fitted in the order you have them laid out from right to left. First item is the thrust bearing which pushes directly on the ends of the pinion teeth. Next is the shim/shims which set the pinion end float. The next item is the top pinion bearing and finally there is the retainer which, with the circlip fitted, holds everything in place. One thing you don't show in your photo is the tiny radial dowel which goes in the semi-circular groove in the retainer and corresponding groove in the pinion housing body. Do be sure you haven't lost that inside the rack itself

Regards
Andy
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PostPost by: andyelan » Thu Mar 27, 2014 7:58 pm

Hi Again William

To answer your first question.

If you assemble the cap and plunger with out shims or the spring you will find that the cap will push the plunger hard down onto the rack. This is not what you want so shims are added under the head of the cap to allow the plunger 0.004" end float. If left like this however the rack will not be held tight into mesh with the pinion so the spring is used to apply a certain load and to do this the spring needs a preload of approx. 4.5mm. What I have found is that in some cases the spring is too short (or the depths of recess in either the cap or the plunger is too deep) so a spacer (In your case a spring washer) is added to increase the spring preload.

Just two things to note. I've never seen a plunger made of nylon so I do wonder if this is original and do not try to increase the spring preload to compensate for a worn rack as it won't work.

Hope this makes sense as I'm not very good at explaining things in writing.

Regards
Andy
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PostPost by: William2 » Fri Mar 28, 2014 9:04 am

Hi Andy, thanks very much for your help. I have got the little dowel for the top spacer. As a point of interest, if anyone requires replacement tab washers for the rack tie rods I a managed to get some from Moss Europe.
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