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Steering alignment question
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Martin A



Joined: 06 Oct 2014
Posts: 17

PostPosted: Sun Oct 30, 2016 3:55 pm    Post subject: Steering alignment question Reply with quote

My question: After aligning the wheels, the car pulls slightly to left. What to do?

I have a 1954 Ford Zephyr. The local garages (I'm in rural France) say they don't do wheel alignment - they take cars to the tyre place for them to do it with their computerised laser setup. But the tyre place tell me they can't do the Zephyr - the bodywork is too wide for their system to be fitted to the wheels.

I did the alignment myself, setting strings parallel to the axis of the car and measuring the distance of the fore of the front wheel rim to the string and the rear of the front wheel rim to the string. I adjusted the alignment and the toe-in is spot on according to the string method. A Gunson Trakrite confirms that the toe-in (of both wheels) is spot on.

The car still pulls slightly to the left. Not strongly but noticable and to the extent that the car can't be driven 'hands off' on a straight road. Tyre pressures are correct and it still pulls to left after the front wheels are swapped.

I'll be grateful for any suggestions how to sort out this remaining defect.
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Penman



Joined: 23 Nov 2007
Posts: 4150
Location: Lancashire

PostPosted: Sun Oct 30, 2016 4:48 pm    Post subject: Reply with quote

Hi
My first thought was road camber effect, then I realised that that should pull you to the right being in France.
I have to wonder if any of the other angles have got disturbed. ie. the castor angle, camber angle.
the castor angle particularly, affects the natural tendency to run straight.
http://www.tpub.com/basae/238.htm

Don't know if this affects it, but I always insist on the steering being centred in it's range before any toe in/out adjustments are made; something which I have found many garages don't do without being told.
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Farmer John



Joined: 18 Feb 2010
Posts: 172
Location: Manawatu NZ

PostPosted: Mon Oct 31, 2016 3:26 am    Post subject: Mk I stg Reply with quote

Hi Martin, you are onto it with your checks here are some more to try. At the back, the tyres of equal diameter, location points of the rear axle including broken leaves, loose shackle bushes, loose U-bolts, spring centre-bolt sheared and axle moved on spring.
Check for a brake dragging with the car on flat, level, concrete or similar. Have the car rolled backwards and forwards about 100mm. place your hands on each wheel in turn, you are feeling for a very very slight "knock", the sound made by a dragging brake as it breaks static friction when the direction changes. A combination of brake adjustment and front wheel bearing play can create a bind condition that is not present with no weight on the wheel.
A likely culprit is the top bearing on Mr Macpherson's strut. Jack the car so the front wheels clear the ground then turn the steering-wheel either way, gently, by varying degrees, what you are doing is judging the resistance and smoothness of the turn and whether the resistance changes when turning back. You know how a bad bearing can feel. Do not be concerned about extremes of lock, just the range within which you usually drive. Spend some time at it.
I should tell you while I am here that the best way we have of checking the bottom outer ball joint is to jack the car in the centre, so that the front wheels are at full droop, then turn the road wheel hard either way, back and forth, in it's steering motion. Its a rhythm sort of thing that must be done with a bit of effort. Now, if you are strong and agile you can do this while watching the joint for play. You could get someone to watch or someone to shake. If you are part of generation iphone make a video.
Let us know how you go.

John
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Martin A



Joined: 06 Oct 2014
Posts: 17

PostPosted: Mon Oct 31, 2016 11:29 am    Post subject: Reply with quote

Hi Penman, John,

Thank you for all those suggestions. Plenty of things to try there. Some of them sound like the sort of things that are not too difficult to detect - if you have experienced them before.

Checking that the steering is centred sounds like the first port of call. I notice that the Zephyr workshop manual mentions to check the toe-out on 20 right lock and 20 left lock, saying that it should be in the range 4 to 5. Although I seem to be able to measure toe-in with adequate accuracy with the wheels straight ahead, I'm not sure that I can measure toe-out with 20 lock.

It also says to check that the steering locks are identical. That should not be too hard to do and I'll have a go at it today.

The Zephyr workshop manual tells you how to check toe-in, camber, and caster using the "Churchill wheel alignment equipment, group No. 121-B". From the illustrations, clearly a formidable piece of equipment.

If the castor angle is wrong, the manual says that a nut on the end of the 'stabiliser bar' will adjust that up to . I don't think that I could measure the castor angle with anything like that accuracy, if I could measure it at all.

If the camber is wrong it tells you to find the part(s) that are damaged or worn, but there is evidently no adjustment for camber.

Many thanks for the various suggestions. I will certainly report on how I progress, although that may take some time.
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Farmer John



Joined: 18 Feb 2010
Posts: 172
Location: Manawatu NZ

PostPosted: Mon Oct 31, 2016 11:03 pm    Post subject: Mk I stg Reply with quote

Hi Martin. The 20deg measurement is for toe-out on turns, ignore that. The outer tie-rods should be exactly the same length, take that into account when adjusting toe-in. The steering wheel position is pretty much cosmetic, worry about that last.
John
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Penman



Joined: 23 Nov 2007
Posts: 4150
Location: Lancashire

PostPosted: Tue Nov 01, 2016 5:52 am    Post subject: Reply with quote

Hi
Father John, just in case anyone thought I suggested that, I didn't mention steering wheel position I was talking about the steering range between locks. The steering must be centered too give the same amount of turn either way
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Bristols should always come in pairs.

Any 2 from:-
Straight 6
V8 V10
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ka



Joined: 03 Dec 2007
Posts: 600
Location: Orkney.

PostPosted: Wed Nov 02, 2016 8:32 am    Post subject: Reply with quote

I have a 'drive over' alignment device, works well if you keep it lubricated, anybody else find a link to one quicker than I can?
But not so good on the Morgan, lack of wheels! on this I use the magnetic laser projectors. Stick then on the hub and project the cross emitted onto the garage door, then move it back six foot, and do the same, if they are perfectly aligned then the vertical of the cross will be in the same place. The horizontal line shows the camber to compare against each other.
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Better three than four.
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jp928



Joined: 07 Jun 2016
Posts: 247
Location: Australia

PostPosted: Wed Dec 14, 2016 1:35 am    Post subject: Reply with quote

There is a formula to calculate caster from camber - measure camber at some specific number of degrees Left , then Right.
http://www.driftworks.com/forum/technical/120178-how-meassure-calculate-caster-angle.html

jp 26 Rover 9
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