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  #11  
Old 27th August 2009, 11:14 PM
georgenewman1 georgenewman1 is offline
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hi guys, i shortened my rack myself from the sierra donor, its simple enough all you need is a 14x1.25 tap to tap the end or the shortened rack and you can make it any length you want, is there some reason for not doing thes that i have missed
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  #12  
Old 27th August 2009, 11:51 PM
londonsean69 londonsean69 is offline
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Quote:
Originally Posted by georgenewman1 View Post
its simple enough all you need is a 14x1.25 tap to tap the end or the shortened rack
What did you tap??

Do you mean you threaded the existing ends of the sierra steering rack? (I assume after cutting them down)

Any particular reason you used M14x1.25? Is that the thread on the existing rack ends (steering ball joints?).

If this works (no reason it wouldn't) it would make the build a lot easier. But doesn't the Sierra have power steering - I don't know, never driven one and I have an Escort rack.

Sorry for so many questions, just interested in how everyone accomplishes stuff

Sean
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  #13  
Old 28th August 2009, 08:41 AM
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Bonzo Bonzo is offline
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As a rule the Sierra was fitted with a manual steering rack. The threads on the track rods is M14 X 2

The XR & 2 Litre DOC Sierra came with power steering & I believe it was an option on other models.

Chris has stated that the Sierra rack is not suitable to use without modification.
It is not a simple matter of altering the length of track controll arms. The problem lies in the rack & pinnion section of the rack, it is too long & needs to be shortened by having it machined.

I had rack extensions made to the book speck & found that they needed to be shortened by 30mm each.
Lucky for me that they had a deep enough bore for me to tap a deeper thread ( M14X2 )
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  #14  
Old 28th August 2009, 02:00 PM
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RAYLEE29 RAYLEE29 is offline
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Hi, George sorry to be the bearer of bad news but what you describe above is totally wrong and will not result in a safe and proper modification and also the handling of the car will be adversely affected.
Why I hear you say
1 the threads on the track rods on the sierra rack are 14x2
2 you cannot simply cut down the rods and rethread they are rolled threads,
rolling a thread increases the od of the thread cutting with a die does not
3 the rack length is totaly wrong it needs the inner ball joints to line up with a theoretical line drawn between the wishbone pivots when the steering is in a dead ahead position (there is a pic of this in the book)
if you dont have the correct rack length you car will suffer from acute bump steer and be very dangerous
I hope you understand what ive written and take it onboard for your own safety
Ray
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  #15  
Old 28th August 2009, 03:25 PM
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squbti squbti is offline
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hi guys , i think the sierra rack is very simmular to the mk2 in its simplicity but is a litle longer & to make iether one shorter is preaty much the same & has nothing to do with the outer rods but it is the inner rod that has to be shortend & rethreaded & now the housing would become too long & also has to be shortend , too much work if you ask me alread have my hans full so i got an mk1 from a friend works just fine & the emperial threads are no big deal. however i will be saving my sierra rack & maybe do that project some other time.
Cheers
Samy
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