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PAS or not PAS? That is the question
romer - 13/1/06 at 09:16 PM

I know these questions have probably been bounced around a million times before, but,

1. On a 7 type CEC (mac#1 / MK Indy) does the steering column HAVE to be non PAS or will a PAS be ok?
Can't remember what the issues where between them.

2. Can an adjustable column be used, and would this matter whether it was PAS or not?

Cheers for any info guys.

Romer


JoelP - 13/1/06 at 09:42 PM

the column is the same irrespective of the rack, though the 'downlink' has larger splines for the PAS rack. Adjustable or non adjustable is just a choice, people usually accept whatever they used though i suspect that the adjustable one makes it easier to get right.

its usually stated as fact that you cant use a PAS rack without the assist, but as far as i know its never been tested.


caber - 13/1/06 at 10:07 PM

a PAS rack is probably quicker i.e. less turns lock to lock but you would have to drain it and strip out the valves to get rid of hydraulic resistance IMHO

Caber


romer - 13/1/06 at 10:25 PM

quote:
Originally posted by JoelP
the column is the same irrespective of the rack, though the 'downlink' has larger splines for the PAS rack.


Is the downlink interchangeable ?? Or would it have to be cut off and the smaller one welded on?

Cheers


romer - 13/1/06 at 10:39 PM

quote:
Originally posted by caber
a PAS rack is probably quicker i.e. less turns lock to lock but you would have to drain it and strip out the valves to get rid of hydraulic resistance IMHO

Caber


Do you know what the ratio would be - I have a PAS rack and could get it off the car before the scrappy comes

Cheers

Romer


JoelP - 13/1/06 at 11:37 PM

i suggested this a while ago, as a cheap alternative to a quick rack. I was told it wouldnt pass a mot or sva unless it was modified to remove all the assist. Myself, i cant see the problem as it works just fine in a normal car when it runs out of fluid.

The downlink just bolts on, so yes, easy to change


romer - 14/1/06 at 12:18 AM

quote:
Originally posted by JoelP
i suggested this a while ago, as a cheap alternative to a quick rack. I was told it wouldnt pass a mot or sva unless it was modified to remove all the assist. Myself, i cant see the problem as it works just fine in a normal car when it runs out of fluid.

The downlink just bolts on, so yes, easy to change


Will look into that next week with the local friendly SVA man

Romer


JoelP - 14/1/06 at 12:37 AM

be sure to let us know


romer - 14/1/06 at 09:55 AM

Yeah JoelP, will put a thread on - assuming it's conclusive and not the usual "slight grey area"

Romer


britishtrident - 14/1/06 at 01:16 PM

Definite MOT fail same as disconnecting a brake servo.


NS Dev - 14/1/06 at 01:33 PM

quote:
Originally posted by romer
quote:
Originally posted by caber
a PAS rack is probably quicker i.e. less turns lock to lock but you would have to drain it and strip out the valves to get rid of hydraulic resistance IMHO

Caber




Do you know what the ratio would be - I have a PAS rack and could get it off the car before the scrappy comes

Cheers

Romer


Sierra PAS rack is 2.8 turns lock to lock, quite quick.

My only worry re. the removal of power assist (started to do this years ago for my RWD Pug 205 rally car that used sierra gp A bits on the front) is the load sensing valve in the pinion shaft. The shaft is actually in two pieces with a flex link in between which operates the valve. I didn't like the idea of this lost motion in the steering, though obviously it's still there with the assistance as well.


romer - 14/1/06 at 11:05 PM

Well NS Dev, got the rack out today and checked the ratio - yup your right it's 2.8 turns.

Anyone know what a non PAS rack ratio is.

I'm defo going to check with the SVA man this next week to see what he has to say about it.
I don't see why putting correctly fitting blanking plugs in where the pipes should have been.

Romer


locost_bryan - 16/1/06 at 01:00 AM

iirc the two-piece pinion has a torque sensing valve that controls the amount of fluid pumped to the PAS piston. One option was to use a bypass hose to connect the two sides of the rack - the rack stll needs the PAS fluid for lubrication.

Check out Keith Tanner's site www.cheapsportscar.com - I'm sure he had an article on depowering a Miata rack.

[Edited on 16-1-06 by locost_bryan]