Lotus Elan

Steering play at particular position.

PostPost by: simonknee » Mon Apr 16, 2012 3:27 pm

Hi all,

Time to sort something that has been niggling for a few years but other stuff has taken precidence and that is some rotational play (5mm or so at the rim) in the steering wheel. So far:

1. Collapsible column is nice and tight. There is no play from wheel to coupling at the rack end.
2. Coupling is new UJ type from Spyder. No play here.
3. Off the ground and wiggle a wheel and the other side wiggles straight away. No play in balljoints or rack ends.

What I did notice today is that the play is present when wheel is dead ahead. There is no play at 1/2 turn in either direction. At a full turn in either direction the play is back.

Does this imply that the pinion gear is worn on one side?
What to do?

The rack is one (of the few) items that I have not touched in my Elan ownership.
Simon
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PostPost by: gjz30075 » Mon Apr 16, 2012 4:05 pm

Most likely the rack. If the pinion gear were worn on one side, the same play symptoms would/should appear again after the pinion rotates 360 degrees. Test to see if that's the case.

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PostPost by: simonknee » Mon Apr 16, 2012 5:49 pm

That's exactly the case Greg,
As I see it a worn pinion is the only way to get these symptoms.

If so what is my next step?
A replacement (refurb) rack or trying to replace the pinion?
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PostPost by: ricarbo » Mon Apr 16, 2012 6:53 pm

Simon, do you think it would help if you took the pinion out, turned it half a turn, then put it back? If the wear is on the pinion only, that should move the sloppy bit away from the straight ahead position to where the self centering should hide it, i would imagine.
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PostPost by: simonknee » Mon Apr 16, 2012 7:12 pm

I found the turn the pinion suggestion in another thread too.

Can you take out the pinion in situ? This would let me see if this actually is the problem.
If I need to get the rack out to do this then I feel I would rather have a proper fix to go back in place.

Also I'm not sure I'd want the play when I am mid corner!
Has anybody tried this trick?
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PostPost by: Elanman99 » Mon Apr 16, 2012 8:02 pm

Simon

I'm not sure whether you could remove the pinion with the rack in the car but its unlikely. Generally you need the rack on the bench to dismantle it and I know I would not even consider an in-car repair.

As suggested the wear is most likely in the rack teeth themselves rather than the pinion, although that too is probably badly worn. As far as I know pinions are unobtainable so a new or rebuilt rack is the only real solution.

I do not know who is currently selling suitable racks. Some time ago a bought a brand new rack from a Triumph specialist thinking I could just transfer the Elan track rods and limit spacers. I was foiled by the fact that the new rack was built with new technology (swaged on, so non dismantleable, ball joints hidden inside the gaiters) perfect for a triumph but useless for an Elan. Some of the so-called 'refurbished or rebuilt' racks that I have seen have not been the best quality but just fitted with thicker shims, re-lubricated, and then given a nice coat of paint!

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PostPost by: Chancer » Mon Apr 16, 2012 8:05 pm

Is it not worth checking out the damper shims first??
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PostPost by: simonknee » Mon Apr 16, 2012 8:11 pm

Ian and Chancer,

I take it that the rack is likely to be worn if the pinion is.
I read that the pinion is harder than the rack.

Yet the play is only at dead ahead and at 360 deg in either direction.
Seems really really unlikely that the rack teeth are worn at these three spots?
Dead ahead yes but exactly one full turn either way, not a chance.

At qtr turn, half turn and 3/4 turn there is no appreciable play at all.

What/where are the damper shims and could they cause these symptoms?
Simon
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PostPost by: Chancer » Mon Apr 16, 2012 8:20 pm

It does sound like a worn pinion then.

The damper is what holds the rack in mesh with the pinion, the rack is guided by a bush in the left hand side of the housing and held into mesh by the spring damper assembly just to the right (IIRC) of the pinion, I assume you have a RHD car.

My memory is hazy but i think if you remove a shim you will increase the preload of the rack against the pinion, this may remove the play you have but given your description will almost certainly make the rack stiffer over the rest of its travel.
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PostPost by: simonknee » Mon Apr 16, 2012 8:21 pm

Ok a bit of googling and I see what the damper/shim is.
It presses on the back of the rack to keep proper engagement with the pinion without binding.

Not sure I can see how this would correlate with the fault?
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PostPost by: simonknee » Mon Apr 16, 2012 8:22 pm

Ah, simultaneous posting!

Maybe it is worth trying as it may not be too stiff over the rest of the range.
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PostPost by: simonknee » Mon Apr 16, 2012 8:26 pm

Another symptom I have is about 10mm of longitudinal play in the wheel which also happens at the pinion.
I have never been really bothered about this so had forgot but is this indicative of a problem with the pinion too?
I assumed that this is a just one of those things. Is it?
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PostPost by: simonknee » Mon Apr 16, 2012 8:30 pm

I say the longitudinal play happens at the pinion, to be honest I have to properly test this...
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PostPost by: Elanman99 » Mon Apr 16, 2012 8:35 pm

There should be no axial movement of the pinion. If it moves 10mm you need to fix it quick, another 10mm and the teeth would be disengaged!

It sounds af if the pinion bearings have been displaced (circlip retains them I think) or the bushes have broken up, maybe the aluminium housing is cracked, either way its not good.

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PostPost by: simonknee » Mon Apr 16, 2012 8:44 pm

I'll have an investigate tomorrow. Not going to tug too hard on the wheel on my way home tonight then! :shock:
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