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More on steering.....


Delberts Wallet

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Its amazing. You bye a car and then try and think of thing that might be wrong. So, should the steering self center easily or is it normal to have to put effort into centering it. My thoughts were not enough toe in but the tyre wear is OK. Any ideas?

Also how easy is it to change the dash board?

 

K8 TRM

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Gareth,

 

Centering is provided by castor not toe in.

 

Check the number of washers between the front lower wishbone front mount an dthe chassis. -

1 = you have little castor

4 = you have loads of castor

 

I have 4 washers in this position, and a 22% wide track rack with 7" (215 section) ACB10's on the front, Steering is not too heavy, and weights up beautifully in corners....

 

 

 

 

 

Arnie Webb

Organiser- L7C Le Mans Trip

To book for this years Le Mans Trip see The Le Mans Trip Website

It really is very very very very full now!!!

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Gareth,

 

Your steering is showing all the symptoms of the fault described and experienced by others. Once the rack is sorted the steering should centre, no problem.

 

If you really want to be sure, you can disconnect bits and pieces in the steering linkage and discover where the stiffness is. 10:1 its the rack.

 

There is an adjustable bush over where the pinion acts on the rack. (Big lock ring.) It is better for this bush to be slack with a small amount of lash than for this to be tight. You can adjust this yourself in a few minutes, but a top tip is to mark up its current position relative to the rack body before you start with a blob of tip-ex or nail varnish. Then you can adjust by a relative amount and convince yourself that you haven't unwound it ludicrous amounts. A change of 15 degrees is a lot.

 

If you are having to turn the wheel to centre then the car is hugely unsafe.

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Yes on re-reading Gareths description if the car does not self centre by itself some thing is severly wrong. Even with the lowest castor setting there should be some self centring

 

Arnie Webb

Organiser- L7C Le Mans Trip

To book for this years Le Mans Trip see The Le Mans Trip Website

It really is very very very very full now!!!

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I got fed up with the inconsistent feel of my quick rack and the fact that to get it so it felt right you had to run is so slack it would then fail scrutineering/MOT . The key to the problem as Peter suggests is the plastic slipper (bush) under the large screw. Most manufacturers of racks use a small but powerful spring to allow the slipper to 'float' up and down slightly as the rack is moved from lock to lock. The spring then taking up the float. Caterhams manufacturer use what looks like a bent steel washer to provide the same spring tension. The problem with this method is that it doesn't provide enough float up and down as the rack moves lock to lock and the spring effectively bottoms out making the rack go stiff. I spent many a happy hour trying to identify what the problem was and consulted with someone who used to recondition racks (when they used to do such things) . What I did was remove the bent washer and inserted a small powerful 'proper' spring with more 'travel' in it and then adjusted the rack accordingly. The slipper even has a mounting hole for a proper spring so its an easy mod to do. The problem disapeared straight away. Don't worry about the small amount of extra travel allowing the rack to slip a tooth or something like that as even with the bush completely removed and no spring inserted there just isn't enough play to allow that to happen.
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Alex, Sorry I didn't go by dimensions. A local company makes springs and they gave me about 20 all of different sizes and strengths. I seem to recall it was about 20 mm long about 8 mm wide and was difficult to compress with just a finger and thumb squeeze. Not very scientific,true, but trial and error made perfect!
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Arnie is talking about castor. As he says that's mostly what affects self-centreing. Camber is adjusted by shortening or lenghthening the top wishbone this adjustment is self obvious but what's not so obvious is how difficult it can be to get the top ball jount out. Four turns is 1 degree of camber change.

Castor is adjusted by moving the lower wishbone forwards or backwards. It's difficult to describe and easy to see but the inner end of the rear leg of the lower front wishbone is pivoted on a bolt. Between the chassis lugs and the wishbone are four washers these sort of control the end float of the bearing. The standard configuration is two washers in front of and two washers behind the wishbone but these numbers change as you adjust to taste as Arnie has done.

The front leg of the lower wishbone is located by the bolt whose head you can see from the front of the car. The matching number of washers should go between it and the chassis once the rear leg has been set.

Moving the lower wishbone forward, more washers behind gives more castor which makes steering less twitchy, slightly heavier and gives more self-centreing.

If you have two washers either side, no toe-in (wheels parallel) and about 1.5 degrees of -ve camber then it won't be far out and I suggest you look at the rack for stiction.

Sorry for sort of repeating what you said Arnie but I thought I'd try and but into words something which is far more easily understood from a drawing or when looking at the real thing.

 

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It seems as usual I'm living in the past and Arnie is right.

Apparently pre '96 cars have two washers in front of and behind as standard but for some reason the chassis was changed from '96 on and now needs four washers in front of the wishbone. My '98 car has two either side and presumably this gives it more castor than standard. I guess I'll have to try the four washers but it's not the easiest job to do, maybe positive (heavy) steering with loads of self centre is not so bad after all.

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