A Steering Problem

General Chat About Steering.

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scarecrow
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A Steering Problem

Post by scarecrow »

Hiya all, ive got a problem with my steering, that is to say the wheels never return to dead ahead! With any amount of a turns of the steering wheel it will remain at that lock, hence going round in circles with look no hands!!! That problem coupled with having very little feeling at the steering wheel have given me a scare more than once, especially at speed when the slightest curve in the road or pothole results in a battle of over correcting and me swearing a lot. Iam looking forward to my first run down the strip next season and would like to do it more than once.It is PAS and the tyres are wearing evenly.Any answers? Thanks in advance.


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Ian Anderson
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Post by Ian Anderson »

I'd hazard a guess that you are running Tow out rather than toe in on your alignment.

That would make most cars twitchy.

But you also d not state what car you are referring to.


(OK front drive cars can be set to tow out as when under power it will take up slack and bushing to get to neutral / toe in)

Or perhaps you are power steering and the power is set to high cauing lack of feel

Ian
Owner of an "On the Road" GT40 Replica by DAX powered by 3.9Hotwre Efi, worked over by DJ Motors. EFi Working but still does some kangaroo at low revs (Damn the speed limits) In to paint shop 18/03/08.

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ChrisJC
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Post by ChrisJC »

The self centering action on steering is determined by the castor angle on the swivel bearings (king pins, strut, whatever). It has to be set surprisingly accurately, i.e. within a few degrees.

Alternatively, the bearing that the steering pivots on could be seized.

http://www.autozine.org/technical_schoo ... m#Feedback

The whole website is pretty good actually!

Chris.
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scarecrow
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Post by scarecrow »

Thankyou very much gentlemen, sound advice, a good website too chris. i think you've given me plenty go at, i might change the steering pump, for what i dont know yet, i guess only it can be responsible for the lightness, i cant remember seeing any flow adjuster on it. Sorry Ian, my car is a 1978 350 camaro. Thanks lads goodnight.
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Ian Anderson
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Post by Ian Anderson »

Try taking the belt off the steering pump and have a short drive

The steering will be real heavy but may give you some idea of wat is happening

Ian
Owner of an "On the Road" GT40 Replica by DAX powered by 3.9Hotwre Efi, worked over by DJ Motors. EFi Working but still does some kangaroo at low revs (Damn the speed limits) In to paint shop 18/03/08.

kiwicar
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Post by kiwicar »

Hi Chris et all
the comments on that website are worth being carefull of, increasing scrub radius (his measurment D) will result in a tendency for the car to "tramline" in the ruts of the road and turn toward any bump inputs on either wheel, everything I have read over the past 30 years says scrub radius should a minimum, this has been born out by personal expreiance. It also makes the steering very heavy.
His castor angle diagram is also drawn with the kingpin axis the wrong side of verticle for the front of the car, set up like that the steering would be totally unstable.
He is also muddling toe in and camber angle in a way that make no sence to me and drawing conclusions that are not consislant (and doing some funny things with tyre shapes that don't happen.

Try Chassis engineering by Herb Adams isbn 1-55788-055-7.
also Car craft did a series of good articles on suspension set up some time ago which may be on their website.

The set up of caster angle is key to getting the self centering to work, toe in will effect stability a few degrees around center before it is masked by any errors in steering rack geomitry/ placement, RWD car should be running about 1/2 to 1 degree of toe in static with rubber bushes all round, 0 to half degree with all rose joints.
You can measure caster angle by measuring camber angle at full left lock then full right lock, the difference between the two is a good aproximation of caster, cant give you a range for this as it differs with suspension design, citroen, mercades and BMW use a lot with little camber gain with suspension deflection, Lotus Rover ford and VW are the reverse but once you have measured it check it against manufacturers spec.
Normal range for king pin angle is about 7 to 10 degrees, if the car has been lowered alot then this can cause problems as the contact patch of the tyre can wander when the steering angle is changed if camber angle has been corrected but the kingpin angle is wrong for the rest of the geomitry
Sorry for the comments on the site but it is just wrong and potentially dangerous. :chase
best regards
Mike
poppet valves rule!

stevieturbo
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Re: A Steering Problem

Post by stevieturbo »

scarecrow wrote:Hiya all, ive got a problem with my steering, that is to say the wheels never return to dead ahead! With any amount of a turns of the steering wheel it will remain at that lock,
Sounds more like a siezed UJ or something.

Yes, geometry will affect feel, and return to centre. But if its sticking at full lock, there is a SERIOUS mechanical problem.
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http://www.youtube.com/watch?v=XgWRCDtiTQ0

scarecrow
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Post by scarecrow »

ooh eck bit of a can of worms, but all good advice. Plenty to go at this weekend...... with a six yearold whos favorite word is dad, it IS plenty to go at! The car is sorn so cant- better not test drive. So much work to be done so little time.At least i know what to look for now thanks to you guys! I will keep track of the faults and corrections and post them here so others can benifit from this episode. Thankyou all once again and all the best(ETs) for the new year
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