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'56 Caster adjust

Started by pocale, December 18, 2017, 10:01:47 AM

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pocale

The friend's '56 convertible is slightly pulling to right and heavier to steer left.
Typical symptoms of caster difference, imo. The car had a wheel alignment a while ago,
but seems the shop did not have interest to try and understand vintage.

The upper control arm is bolted top-down to the frame, so a shimm there is not the answer, i guess.
What is the easiest way to adjust caster on these Cads?

Thanks.
V8, A/T, RWD - other options are negotiable

Caddy Wizard

Check tire pressure, brake adjustment, and toe-in adjustment first.  Those are all more likely than a caster problem.
Art Gardner


1955 S60 Fleetwood sedan (now under resto -- has been in paint shop since June 2022!)
1955 S62 Coupe (future show car? 2/3 done)
1958 Eldo Seville (2/3 done)

J. Gomez

Quote from: pocale on December 18, 2017, 10:01:47 AM
The friend's '56 convertible is slightly pulling to right and heavier to steer left.
Typical symptoms of caster difference, imo. The car had a wheel alignment a while ago,
but seems the shop did not have interest to try and understand vintage.

The upper control arm is bolted top-down to the frame, so a shimm there is not the answer, i guess.
What is the easiest way to adjust caster on these Cads?

Thanks.

I was told by two of my local repair shops that they show the specs on wheel alignment for the 1956 Cadillac (all models), not to trust what they may or not have in their system I’ve always take the specs from the Service annual with me to validate.   ;)

Since you mention the shop was not open to your friend’s comments, the question is did they do the correct full alignment caster/camber/toe-in-out and did they use the upper support arm eccentric tool J-4691 or equivalent?   ???

I would not be surprise if they did not use it as they may not have one of this handy on their shop and it is needed for both caster and camber per the Service Manual.    ::)

Just my ½ cent.
J. Gomez
CLC #23082

pocale

thanks for the responses.
i would like to adjust the caster myself, a little, to see what difference it makes. then maybe a new pro alignment.

how do you adjust caster?
V8, A/T, RWD - other options are negotiable

J. Gomez

Quote from: pocale on December 18, 2017, 11:15:29 AM
thanks for the responses.
i would like to adjust the caster myself, a little, to see what difference it makes. then maybe a new pro alignment.

how do you adjust caster?

Juho,

There are several tips on getting a DIY rig setup for the caster and camber that you can search on Google. I just did mine for a quick validation before I can take it to a shop for a correct alignment.

One point is if you do not have the upper support eccentric tool as shown on the Service Manual section 4 Fig. 4-30 you will not be able to get it done.  :(

The tool is a 1 7/16” crow-foot wrench type but the thickness is about 0.38” unfortunately the current crow-foot tools are about twice that thickness which would not fit at the upper control arm.   >:(

Good luck..!
J. Gomez
CLC #23082

m-mman

NO! dont try it on your own. . . Moving the upper control are affects caster, camber AND toe in! 
The three adjustments are dependent on each other. Changing one can alter the others. (kinda like points and timing)  Once you change one you need to recheck the others.

You can check the toe (in or out) with a tape measure in you garage.
But to REALLY check caster and camber you need a rack (car must be level) and the gauges to properly measure. In caster & camber you are talking about 1-2 degrees of difference. Changes that you really cant see with your naked eye.

If you start making changes in your garage without the proper tools you can end up making some significant changes that would require the proper tools to set correctly again.

See reply above. Check the things that you can check and adjust in your garage BEFORE you try moving the control arm. 
1929 341B Town Sedan
1971 Miller-Meteor Lifeliner ambulance
Other non-Cadillac cars
Near Los Angeles, California

CLC #29634

Glen

Its been a while since I worked on a ’56, but I checked and confirmed the pivots for the upper control arm are eccentrics.  To adjust caster, you turn the front and rear pivots in opposite directions.  That moves the outer end of the control arm forward or backward.  Moving the pivots in the same direction moves the outer end in or out to adjust camber.  Max movement on the pivots is one-half turn. 
After making those adjustment then you need to check toe in.  Toe in adjustment is done with the tie rod adjusters.
My experience is that to adjust the upper pivots the weight of the car must be off the wheel, meaning you have to jack the car up, make the adjustment lower the car and normalize the suspension then take the measurement.       A few rounds of that will wear you out. 
Glen Houlton CLC #727 
CLCMRC benefactor #104

m-mman

#7
To take the weight off of the adjustments on the upper control arm you put the jack UNDER THE LOWER CONTROL ARM and lift it high enough to get the tire off the ground.

Doing so supports the car's weight on the spring BUT means there is no weight on the upper control arm.

Depending on the car and design of the inner fender panel you can lift the lower control arm, remove the upper mounting bolts spin the control arm around and change bushings without breaking the upper ball joint attachment. There is no weight or stress on the upper arm.
1929 341B Town Sedan
1971 Miller-Meteor Lifeliner ambulance
Other non-Cadillac cars
Near Los Angeles, California

CLC #29634

Dave Shepherd

Camber affects directional pull more than camber.  To set caster camber you really need turn plates. In my shop  we try to get some positive caster if the car has radials, but this can be difficult as that may upset camber settings.. Btw if aligned at a  shop on modern equipment, and you don't get a final printout, consider it wasn't done.

Roger Zimmermann

Quote from: Dave Shepherd on December 19, 2017, 02:59:22 PM
Camber affects directional pull more than camber.
Dave, caster or camber?
1956 Sedan de Ville (sold)
1956 Eldorado Biarritz
1957 Eldorado Brougham (sold)
1972 Coupe de Ville
2011 DTS
CLCMRC benefactor #101

Dave Shepherd

Yikes, the brain skipped a beat, camber is more of an issue for pulling than caster, regarding steering lead.

Jay Friedman

I agree with m-mman.  It's best to have this done by a professional in a shop equipped with wheel alignment tools and equipment. 
1949 Cadillac 6107 Club Coupe
1932 Ford V8 Phaeton (restored, not a rod).  Sold
Decatur, Georgia
CLC # 3210, since 1984
"If it won't work, get a bigger hammer."

Roger Zimmermann

Jay, I don't know the situation in the US, but some years ago, I tried to have the front wheel alignment corrected at my '56 de Ville because the car was pulling on one side. The shop I went had no idea how to do it, (had to explain with the shop manual copy) had of course not the special tool for the caster/camber. At the end, they just could record the existing values and I corrected the caster/camber myself at home...
1956 Sedan de Ville (sold)
1956 Eldorado Biarritz
1957 Eldorado Brougham (sold)
1972 Coupe de Ville
2011 DTS
CLCMRC benefactor #101

J. Gomez

Roger,

I do not believe there is much differences between the US and European shops that perform front end alignments, just my personal views.

In my case the two shops I’ve inquired on their capabilities to do the job, one told me "sure no problem just bring it in". After a few hours I was told they could not do it after all since they did not have the proper tool, and same as you they just gave me the printout.  :o

The second shop the older tech told me, I do not have the tool on my tool box but I do have one at home so just schedule the appointment and I’ll bring it with me. In talking with him he knew exactly what was needed and the tool for the upper arm eccentric adjustment as he did other GM cars.

The key point is having the shop dealing with older cars is a challenge for us, the majority are more proficient with newer cars and since they want to sell you the service you have to be more inquisitive in their willing to listen and to change their methods when it comes to older cars. Which unfortunately they are few that would take the time and effort.  :(
J. Gomez
CLC #23082

Roger Zimmermann

Agree, Jose. Unfortunately, there are less and less older people in such shops. In Europe, the old tools are scraped, in the US, they go to eBay!
1956 Sedan de Ville (sold)
1956 Eldorado Biarritz
1957 Eldorado Brougham (sold)
1972 Coupe de Ville
2011 DTS
CLCMRC benefactor #101

J. Gomez

J. Gomez
CLC #23082

Jay Friedman

#16
Here in the Atlanta area we have Weaver Brake & Tire Inc., a shop which has the right equipment and has aligned the wheels of several Cadillacs belonging to local CLC members.  When I took my car there for wheel alignment the 1st time, just in case I brought along my '49 shop manual to show the mechanic who would do the work the specs, the eccentric in the upper arm and how to do the adjustments.  He was a relatively young guy (though most everyone is younger than me these days) and told me he was familiar with the procedures after having done a number of old Cadillacs.  He did a great job, including the info that my '49's camber had needed a bit of correction on one side.  He then took the car out for a road test to make sure it steered and braked correctly.  So there is hope. 
1949 Cadillac 6107 Club Coupe
1932 Ford V8 Phaeton (restored, not a rod).  Sold
Decatur, Georgia
CLC # 3210, since 1984
"If it won't work, get a bigger hammer."