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Discussion Starter #1
The PO of my spider spent a lot of money on suspension & steering work & brakes,
Front and rear rotors, pads and hoses, Rear trailing arm bushes, front upper & lower ball joints, I don't know much about wheel alignment, but from what I can see someone stuffed it all up, the front wheels had so much positive camber they looked like the rear of a VW Beatle, so I decided to have a go at adjusting the camber my self, looks like someone has mucked around with the caster rod adjustment, going by the position of the adjustable top arm, is this too much positive caster?
 

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But Mad North-Northwest
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Look closely at the bushing in the center of the picture where the upper arm attaches to the body. Is the rubber in the bushing bulging out of the bushing to the front?

There was a bad batch of adjustable upper arms a few years back where the bushing was not properly bonded. End result was that it would bulge out and look like yours does. Too dark in your picture to tell if that's the problem, though.
 

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Discussion Starter #3
Thanks Tom
I know what you mean about that bushing, here's a better picture,
The bush looks ok to me but it's the angle of the top army's it comes out of the body mounting I think the adjustment nuts have being Rubbing against the rear and the arm is resting on the left of the rubber bump.
 

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But Mad North-Northwest
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105 Junior,

The degree of positive caster depends on what you do with the car. Here's my experience: Decades ago, I noticed that the Alfa GTA Junior of one of my autocross competitors seemed to "turn in" much better than my 1971 1750 Spider. He revealed that a co-worker engineer at Ford recommended he add as much positive caster as the adjustment allowed (similar to your pictures). I learned that additional positive caster gave additional negative camber on the outside wheel (only) when cornering - hence more front grip - but that the steering effort went up since turning the wheel raised the car, and the return to center was much stronger. I finally tried the extreme adjustment on my car, and the increased front end grip changed the handling balance to the extent that I disconnected the rear sway bar to reduce the resulting oversteer. This caster adjustment was a good technique with the narrow tires of the day but I had to gradually back off as my tire width continually increased to what I use now; 275/35x15. Too much camber, whether from caster or camber adjustment, meant the outside of the tire contact patch was lifting off the ground and I used a tire pyrometer to optimize the suspension setting.

This information is for a dedicated autocross car and may have no application for use on your car, but I offer my experience for your information. Others may offer differing views that satisfied their needs.

... so I decided to have a go at adjusting the camber my self, looks like someone has mucked around with the caster rod adjustment, going by the position of the adjustable top arm, is this too much positive caster?
 

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From " Prepare to Win" by Carroll Smith:
CASTOR. "Not enough leads to very light steering, insufficient self return action and straight line instability. Too much makes the steering heavy, gives excessive wheel camber while steering and makes steering response slow. Getting the castor even from left to right is more important than getting it exact."

If the castor is uneven the car will pull to one side when going in a straight line and the pull will be to the side with the most castor.
 

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If the castor is uneven the car will pull to one side when going in a straight line and the pull will be to the side with the most castor.
It needs to be a bit more specific than that. The car will pull to the side with the most negative caster or the least positive caster.

So if the car is pulling to the left ,say, you can correct it by increasing positive caster on the left side. You do that by increasing the length of the caster rod.

OR, you could decrease the caster on the right side by shortening the caster rod.
 

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It needs to be a bit more specific than that. The car will pull to the side with the most negative caster or the least positive caster.

So if the car is pulling to the left ,say, you can correct it by increasing positive caster on the left side. You do that by increasing the length of the caster rod.

OR, you could decrease the caster on the right side by shortening the caster rod.

if the car is pulling to one side, doing asymetrical castor is most definitely NOT a solution. i would not hesitate to say it is exactly the wrong thing to do. the castor needs to be the same on both sides because it dynamiclly changes the tire loadings as a function of the akerman as the wheels turn left or right. having asymetrical castor will give you a car that has pretty different handling characteristics turning left vs turning right. if you have a car that " pulls " in one direction or the other in normal straight line travel you need to find and fix exactly what is mechanically wrong thats doing that not introduce some bizzare alignment settings...
 

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Steve I'm not suggesting anyone should use caster adjustment as a way of getting over other faults, my comments are in the context of the original post:

If the castor is uneven the car will pull to one side when going in a straight line and the pull will be to the side with the most castor.
So yes, you need to ensure that other parameters like camber are correct and the caster is as close to the same as possible both sides. But alignment shops will tweak the caster, within limits, to counter the effect of the camber of the road, for example.
 

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Discussion Starter #11
That's the camber bush, not the caster bush, correct? Here's a thread on the subject:

http://www.alfabb.com/bb/forums/suspension-steering-brakes-wheels-tires/91980-105-upper-arm-inner-bushing-problem.html

You can go with poly, but another option is to use a lower a-arm bush on the upper a-arm. It's a stiffer bushing and works well in that location. See thread above for more info.
The picture shows the top arm bush, i was talking about replacing the caster bush with poly bush as the rubber one has separated, I've been getting a lot of clunking sounds coming from the front suspension when I brake suddenly, or drive over cats eyes, I think I found the source of the clunking, there are signs the top arm is hitting on the body due to the angle it comes out of the mounting box, I'm not getting any left or right pull on the steering, the other issues are a bit more complex, I'm in the process of removing and replacing the steering box with a refurbed one as the housing is cracked, and the chassis rail where the steering box mounts has cracked or separated, when you wobble the steering from side to side I can see the the left & right sides of the rail have separated from the U Chanel and are moving in opposite directions, does anyone have experience in repearing this?
 

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there are signs the top arm is hitting on the body due to the angle it comes out of the mounting box,
You really, really don't want that happening when you are running adjustable upper arms. Irrespective of handling characteristics, dialing in so much caster that the arm impacts the frame as the suspension moves runs the risk of fracturing the threaded portion of the arm due to fatigue. If you were running the stock (e.g., solid, non-threaded) arms, I'd say "don't worry about it" - but a threaded rod is more sensitive to cracking from repeated bending than a solid tube.

If you need that much caster, and want to retain the adjustable arms, one patch is to press in the bushing off-center, so the inboard end of the rod is as far forward as possible. That will allow its outboard end to be positioned a little more rearward before it interferes with the frame.
 

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You really, really don't want that happening when you are running adjustable upper arms. Irrespective of handling characteristics, dialing in so much caster that the arm impacts the frame as the suspension moves runs the risk of fracturing the threaded portion of the arm due to fatigue. If you were running the stock (e.g., solid, non-threaded) arms, I'd say "don't worry about it" - but a threaded rod is more sensitive to cracking from repeated bending than a solid tube.

If you need that much caster, and want to retain the adjustable arms, one patch is to press in the bushing off-center, so the inboard end of the rod is as far forward as possible. That will allow its outboard end to be positioned a little more rearward before it interferes with the frame.

there is no material upside to a lot of castor in a street car. all you need is a couple of degrees for good solid straightline stability . the camber gain and weighting of the unloaded wheel that results are , for all intents and purposes completely meaningless in 99.9 % of what a street car does and if you are racing the car using the stock geometry , the extra castor isn't going to fix the lack of camber gain, bad roll center migration , and all the rest that the stock geometry is weak in, then extra castor isn't going to fix anything anyway.
 

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Discussion Starter #14
You really, really don't want that happening when you are running adjustable upper arms. Irrespective of handling characteristics, dialing in so much caster that the arm impacts the frame as the suspension moves runs the risk of fracturing the threaded portion of the arm due to fatigue. If you were running the stock (e.g., solid, non-threaded) arms, I'd say "don't worry about it" - but a threaded rod is more sensitive to cracking from repeated bending than a solid tube.

If you need that much caster, and want to retain the adjustable arms, one patch is to press in the bushing off-center, so the inboard end of the rod is as far forward as possible. That will allow its outboard end to be positioned a little more rearward before it interferes with the frame.
I agree with you Jay, the alignment was like this when I bought the car, I think the alignment was done when the adjustable top arms and bottom ball joints were replaced, the car is completlely stock so I don't know why the caster is set the way it is but going by the threads on the caster arm someone has adjusted the camber settings not to long ago, it's the same on both sides,
 

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For the benefit on Anglo Spider
From "Tune to Win" by Carroll Smith, page 138
Front Wheel Castor Uneven
"Car swerves in one direction (toward the side with the high castor setting) in a straight line."
 

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But alignment shops will tweak the caster, within limits, to counter the effect of the camber of the road, for example.
With camber being even I have adjusted thousands of cars to compensate for the road crown. 1/2 degree to the negative in relation to the other side, centered on the factory specs, to the side the crown is on (the left here in the colonies). The same effect can be achieved by keeping the caster even and giving 1/4 degree camber lead to the crown.
 

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But Mad North-Northwest
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Yep, that's how the local alignment shop sets up cars: bit of caster on one side to compensate for road crown.
 

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With camber being even I have adjusted thousands of cars to compensate for the road crown. 1/2 degree to the negative in relation to the other side, centered on the factory specs, to the side the crown is on (the left here in the colonies). The same effect can be achieved by keeping the caster even and giving 1/4 degree camber lead to the crown.

are you serious ? you are saying that you intentionally put a biased alignment on your car to account for a road condition that isn't the same or similar or even in the same galaxy even close to the same from one mile to the next on any two roads anywhere ? i would respectfully suggest to you that a biased alignment for " road crown " on some 2 lane secondary road that hasn't seen maintainance since 1960 isn't going to be anything at all what you want on rt 95 at 85 mph. and thats exactly why street cars have symmetrical set ups... because they actually have to operate correctly an all kinds of roads.

you will forgive me if i say directly that any alignment shop that is telling you they are " aligning for road crown " is simply full of sht.
 

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I was speaking from the experience of ~10,000 alignments with the requisite rebuilds and very high customer satisfaction,but what do I know...
 

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you will forgive me if i say directly that any alignment shop that is telling you they are " aligning for road crown " is simply full of sht.
Well, that's two professional opinions versus...uh...let me see here..."some guy on the internet who doesn't know how to capitalize". Think I'm gonna go with what my shop says, Steve :D
 
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