Slimy38
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| posted on 28/5/18 at 10:19 AM |
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Steering column bearing on MX5 Haynes cars
Following the Saturn build plans to use an MX5 donor, I've used the upper steering column and extended the lower column to reach the rack. On
the plans it talks about fitting a bearing to the firewall, but I don't understand what value it's adding.
The upper column is fixed in two places and doesn't move, without the bearing the lower column is unsupported but with only two UJ's in
the structure there is nothing to support.
The original Sierra design has no similar bearing, so why is it there?
And secondly, the hole in the firewall is large enough for the upper UJ to fit through, but that seems to contradict the concept of a
'firewall' as it's not sealed. Is there anything in the IVA (or in normal use) that requires the cabin to be sealed from the engine?
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bonzoronnie
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| posted on 28/5/18 at 11:21 AM |
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The original Sierra firewall/bulkhead had a large rubber grommet & plastic bush fitted.
To my mind that acts as a steering column support bearing/bush.
A common MOT failure in my days of driving and owning Sierras.
Andy at Saturn replaced that lot with a self centring bearing assembly to accommodate the MX5 set up.
I can't remember the part number of said bearing.
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Slimy38
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| posted on 28/5/18 at 11:41 AM |
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quote:
Originally posted by bonzoronnie
The original Sierra firewall/bulkhead had a large rubber grommet & plastic bush fitted.
To my mind that acts as a steering column support bearing/bush.
A common MOT failure in my days of driving and owning Sierras.
Andy at Saturn replaced that lot with a self centring bearing assembly to accommodate the MX5 set up.
I can't remember the part number of said bearing.
I already have the bearing, but as I was bolting it into place I was trying to work out what it actually did. Interesting that the original fit was an
MOT failure.
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bonzoronnie
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| posted on 28/5/18 at 12:18 PM |
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On my Sierra based build, there was a fair bit of play in the column assembly without the bush fitted.
The same was true on the original Sierra car when the bush was knacked.
Quite noticeable when you grab the steering wheel & firmly rocked it up/down & side to side.
The MOT failure would state " Excessive play in steering column "
Not too familiar with the MX5 donor build but guessing some sort of intermediate support would be needed between steering wheel support bracket &
steering rack.
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ianhurley20
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| posted on 28/5/18 at 05:59 PM |
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Didn't use it on mine. Standard MX5 column, hole in bulkhead, two legs at bottom of column bolted to bulkhead and MX5 rubber grommet thing used
to make some sort of seal. UJ also used and column then extended with extra UJ added to get round alternator to the rack with support bearing en
route. No problem at IVA
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