ellisb7
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posted on 13/5/02 at 01:44 PM |
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Steering Rack Shortening
Can anyone help with procedures and drawings for shortening steering racks and housings? Machining - no problem. Brian
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Dunc
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posted on 13/5/02 at 01:54 PM |
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I shortened my steering rack off the sierra. I dismantled it then took 120mm out of the centre of the ali housing and made an ali sleeve and tig
welded it together again. The cast is quite poor and not very round so when I put them together without the sleeve they didn't mate up.
I turned 120mm off the rack on a lathe for accuracy and drilled and tapped a new thread, I think it was M14 fine but best checked. I then made to 2
60mm extensions to fit between each of the track rods and track rod ends to keep the same wheel track.
Let me know if you want me to post the pics.
Dunc
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ellisb7
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posted on 13/5/02 at 05:34 PM |
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Hi Dunc
Would appreciate pictures. Brian
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Simon Mc
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posted on 13/5/02 at 06:42 PM |
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Dunc,
I would also like to see some pics. Does the Escort rack fit the sierra uprights or does the sierra rack have to be shortened?
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ellisb7
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posted on 13/5/02 at 07:16 PM |
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Dunc
I assume the sleeve goes inside and both the sleeve and the bores are machined?
Brian
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leggin
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posted on 13/5/02 at 09:21 PM |
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why cop the rack in half its a lot easier to shorten the arms and a hell of a lot safer
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Simon Mc
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posted on 13/5/02 at 10:11 PM |
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Dosnt that effect the geometry, having the steering arms pivot in the wrong place? I am no way an expert in this, but i think the reason for
shortening the rack was to avoid this?
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Dunc
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posted on 14/5/02 at 09:15 AM |
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Brian- The sleeve fitted over the cast, had an internal lip to keep it central between the two halves. The condition of the internal cast meant it
would be difficult to insert a sleeve while keeping the clearance for the rack. The changes in the OD of the cast meant that the two halves couldn't
be welded together effectively, in my case anyway.
Leggin- I had to chop the housing in half because I needed to keep both ends, where the nylon bearing are held, and the mounting flanges. It was only
the end of the rack that was cut off and re machined, the side away from the gearing. I could have shortened the arms but it would have made my
steering geometry wrong and I wanted to keep the same track roughly the same as the rear( within a few mm)
Simon- You're right about the geometry, each case is different and you need to try and optimise the position of the rack to avoid adverse effects
while cornering or hitting bumps. With the inconsistances in Mr Champions book regarding metal lengths I'm not sure if a lot of time was spent
looking at optimising the front suspension geometry much further than a 'looks about right' attitude. Might be wise to analyse your own geometry.
As regards to the escort rack, I'm not sure, but it will not be difficult fit a sierra track rod end onto an escort track rod. The thread might be
the same on both or an adapter can be easily made up. Can anyone confirm the thread size for the track rod from an escort? From memory the sierra is
M14 std.
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