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1970 DeVille Ssteering won't center

Started by jepstr67, December 29, 2012, 02:23:33 PM

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jepstr67

Hi, First post here.

I've had a 1970 DeVille since, well forever, it was my first car.  I bought it in 1980 when I was a Jr. in high school. Friends, girlfriends and the like all consider the Cad a big part of our past.  However, I had to stop driving it. It works fine and all in town, but the steering has a slight resistance so it won't track properly on the highway. If I turn in a circle and let go fo rthe wheel, most cars will come out of the circle and eventually let the castor bring the path to a straight line. My Cad will orbit in about a 500 foot diameter circle forever. This means, on the highway you have to constantly steer, rather than letting the car follow the road and making slight adjustments as needed. It completely wears a person out to drive very far like that.  I'm convinced the resistance is in the column, but I'm open to suggestion.

FIY, Over the past 5 years, I've had 3 different gear boxes and every part know to exist in the front end has been replaced at least one, some twice, by 2 different shops, in an attempt to cure this. I'm now about $3000 into it and it still won't steer properly.

Makes me crazy!

The few the proud the 1970 DeVille convertible. The Last Rear wheel drive soft top Cad.

BReyes

Nice you have your first car so many years. My first car was a 75 CDV. Sold it to a family member after graduated high school about the same time as you. Yes your car may ride at speed with ease of one finger.

With many new suspension parts on your car, the 4 wheel alignment before and after numbers should pin point any problem corners and how solved. That you replaced the gear box already several times is discerning but that is probably where to begin. I would do only one thing at a time from this point on. What does the alignment tech say(print out)?

Regards,

Bernard

Dave Shepherd

#2
Something could be binding in the steering I would disconnect the pitman arm from the center link and turn the wheels see if there is any binding, if not, reconnect the center link and try backing off the p/s top cover pitman shaft adjustment maybe 1/2 turn, after doing this check for excess free play in the steering response, if ok retest the car.

The Tassie Devil(le)

Although you have owned it for so long, can you remember when the problem started to appear?   Was it a slow progression, or a sudden thing?

Recheck all measurements, including wheelbase, track, front and rear, tyre pressures, and most definitely have a good wheel alignment performed by a reputable shop.

Check all ball joints, bushings, and the shape of the flexible coupling where it connects the steering column to the box.   This should sit nice and circular, without being twisted out of shape.   You don't say where you live, but is there a possibility that the chassis could be rusting, and possibly bending, putting a strain at the steering column to box coupling?

One thing you should do is to jack up the car, and with the front wheels off the ground, rotate the steering wheel from lock to lock, with the engine running, and notice if there is much difference in the "steering wheel feel".

Bruce. >:D
'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'74 Chris Craft Gull Wing (SH)
'02 VX Series II Holden Commodore SS Sedan
(Past President Modified Chapter)

Past Cars of significance - to me
1935 Ford 3 Window Coupe
1936 Ford 5 Window Coupe
1937 Chevrolet Sports Coupe
1955 Chevrolet Convertible
1959 Ford Fairlane Ranch Wagon
1960 Cadillac CDV
1972 Cadillac Eldorado Coupe

76eldo

If you can't find anything mechanical or any binding, get the alignment looked at again.
I forget which, caster or camber but whichever one it is, one of these settings can add or subtract from the cars ability to self correct after a turn. I'm thinking caster.
If its totally off it keeps the wheel pointed where its aimed and won't turn back in its own.

Brian
Brian Rachlin
Huntingdon Valley, Pa
I prefer email's not PM's rachlin@comcast.net

1960 62 Series Conv with Factory Tri Power
1970 DeVille Conv
1970 Eldo
1970 Caribu (?) "The Cadmino"
1973 Eldorado Conv Pace Car
1976 Eldorado Conv
1980 Eldorado H & E Conv
1993 Allante with Hardtop (X2)
2008 DTS
2012 CTS Coupe
2017 XT
1956 Thunderbird
1966 Olds Toronado

Dave Shepherd

Correct on the caster, but to have the symptoms he is having th4e caster would be so far negative it would almost be undriveable in the straight away, plus there is not normally that range of adjustment built in, inless the control arm bushings are all bad, but as we are saying many things can cause this and no one can really inspect this car. The alignment specs showing set back and thrust angle would help.

TJ Hopland

Caster is the alignment parameter that is the most different between bias and radial tires.   Back in the day when people remembered that a lot of the shop guys knew that and if you were putting on radials they made the adjustment.  Now days when a lot of shops techs were born 20 years after bias tires disappeared they just dont think of it and put the cars to original specs.  If I am remembering correctly most of the time the caster spec on bias tires is often close to zero.   Going to radials on a smaller car often is in the -1 to -3 range.  The big land yacht stuff I have seen as high as -5.    If you started out at zero and had a worn bushing or something you would get one wheel that wanted to center and the other would be at the mercy of the toe or how its bushings were worn. 

I had a 66 mustang that was just horrible to try and drive at highway speeds.  I had changed a bunch of bushings and such and was about to do the steering box when I stumbled on the info about caster.  I checked it and sure enough it was pretty much at zero.  I think I put it to about -2 and the car handled much better.  Steering box was still shot, you could move the wheel about 6" without making the car move but with the caster set it would drive normally.   

I just spent a few weeks fighting rear bump steer on a newer car.  Found a bushing that barely had enough wear in it to notice but by the time that transferred to the wheel it was almost 1/8 of an inch which was enough to make the car hard to control.   
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

Dave Shepherd

The normal recommendations when putting radials on our old cars is to try and get to positive caster this allows the car to track better, in my shop I have excellent succes with this, radials tend to go in the direction they are pointed, hence, the steering can be twitchy making minor corrections at highway speeds, with some positive caster car wants to come back to straight, both Coker and Diamondback agree on this issue.  I shoot for 1.0-1.5 positive if possible.  some cars you cannot get this as they had -1.5 from the factory and the range of adjustment was not there.  Of course not every car responds the same to this and some do not change at all, but I can tell you generally this is the way to go.  You can see the difference in specs on some cars between having p/s vs no p/s. The p/s car has more positive caster, again generally.

jepstr67

I've had shops fool with the alignment extensively. We've played with the castor quite a bit. I'm pretty sure it is not an alignment problem. I took the car into my shop from the shed yesterday. This week, I'm planning to lift the front wheels off the ground by spacing the lower control arms up from the ground, so as to simulate the car still sitting on the wheels.  Then I'm going the "feel the steering" as suggested.  You can feel it in the steering already. It takes a little nudge to get the wheel to turn. Then it turns freely.

It has been so long I can't remember, but I think the problem started with the first gear box replacement. The reason for that replacement was that the power steering had become weak and the steering sloppy at 200K miles. My suspicion is there is side pressure on the bearing at the base of the column, near the gearbox caused by poor alignment.  If I recall correctly, that is an non-lubricated plastic bushing, not a bearing.

Thanks much for the many suggestions. I'll keep everyone posted.

TJ Hopland

I must be miss remembering + and -.   So if we are looking at the left side of the car and we say that the lower control arm is our fixed center point.  If we move the top forward (left since we are standing on the side) is that positive or neg caster?
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

Dave Shepherd

TJ, positive caster is the rearward tilt between the upper and lower ball joints, like a motorcycle front fork, that is pos caster. What you stated would be going towards neg. caster. And yes I do not believe this his his problem.

76eldo

I do all of the mechanical work on my cars myself, but if i get totally stumped by something I would consider a safety issue, like brakes and/or steering, if it's not an obvious thing, I would take it to a qualified mechanic.

I've lost brakes on a highway exit ramp, going downhill, brake pedal to the floor, and it ain't fun.  Losing steering control might be worse.

Good luck, and i hope you figure it out.

Brian
Brian Rachlin
Huntingdon Valley, Pa
I prefer email's not PM's rachlin@comcast.net

1960 62 Series Conv with Factory Tri Power
1970 DeVille Conv
1970 Eldo
1970 Caribu (?) "The Cadmino"
1973 Eldorado Conv Pace Car
1976 Eldorado Conv
1980 Eldorado H & E Conv
1993 Allante with Hardtop (X2)
2008 DTS
2012 CTS Coupe
2017 XT
1956 Thunderbird
1966 Olds Toronado

jepstr67

Yes. It is worse. On my Jeep CJ I had the rod from the pitman arm come loose from the front wheel at the tie rod end last week. Fortunately I was just stopping at a light and only moving 1/4 MPH when it happened.

I've blown a brake line on the freeway and not known it as well. That off ramp is a wild ride with no brakes. Went right through a red light,  a conveniently timed slot in the traffic was my friend, and I buried the right front wheel in the snow drifts along the road to slow down.  I had a single master on that vehicle. I had to pinch of the rear brake line and then I was able to drive home on back roads.

As stated before. "qualified mechanics"  have tried and failed to fix my Cadillac.   I have as good or better skills than most mechanics do, but I usually use mechanics to save time.  For projects like this where qualified mechanics are stumped, I prefer to take the time and do it myself so it is really done right.  Once I discover the problem that they are unable to find, I may have them fix it, but the diagnosis seems to elude them.

Todd

TJ Hopland

I don't remember the U joints on the steering shaft in this era being that complex but on an 05 I had a really strange steering issue that I thought was the fancy electronic stability system.  Turned out to be the U joint.  I was not like I could not steer it was just weird.   Shop guy brought me the old shaft / joint and I could not flex it at all with my bare hands. 
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

C.R. Patton II



Hello Todd

Welcome to the Cadillac & LaSalle Club Forum.

The 1970 DeVille is a very nice car with an exceptional engine. You may want to purchase a Cadillac Shop Manual.
All good men own a Cadillac but great gentlemen drive a LaSalle. That is the consequence of success.

The Tassie Devil(le)

G'day TJ,

No "U" Joint in these cars, just a Rag Joint.

Bruce. >:D
'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'74 Chris Craft Gull Wing (SH)
'02 VX Series II Holden Commodore SS Sedan
(Past President Modified Chapter)

Past Cars of significance - to me
1935 Ford 3 Window Coupe
1936 Ford 5 Window Coupe
1937 Chevrolet Sports Coupe
1955 Chevrolet Convertible
1959 Ford Fairlane Ranch Wagon
1960 Cadillac CDV
1972 Cadillac Eldorado Coupe

TJ Hopland

Same concept though if it was very stiff for some reason, perhaps its worn out and it now got some binding issue from the metal on metal contact?    Where is the bushing he is talking about located?
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

Glen

Does this help? 
Glen Houlton CLC #727 
CLCMRC benefactor #104

jepstr67

Quote from: C.R. Patton II on December 31, 2012, 11:38:49 AM

Hello Todd

Welcome to the Cadillac & LaSalle Club Forum.

The 1970 DeVille is a very nice car with an exceptional engine. You may want to purchase a Cadillac Shop Manual.

Yes. I have 2. One I use by the car and one I keep in the house to read up on projects.

jepstr67

Quote from: The Tassie Devil(le) on December 31, 2012, 06:12:03 PM
G'day TJ,

No "U" Joint in these cars, just a Rag Joint.

Bruce. >:D

Bruce,

I finally had time today to look into this. There seems to be some pressure on the rubber vibration joint. It seems the gear box was pushing up on the column and the previous mechanics had not allowed the splined coupling to slide up the steering shaft in the column to a point of relaxed tension. Could it be this easy? just eliminate the side pressure on the column bearings?

Todd

1970 DeVille Convertible
1960 Willys Utility wagon
1967 Jeepster Convertible
1970 AMC Gremlin
1982 Jeep J10
1983 Jeep Scrmbler CJ8
2006 Jeep Commander