Whats wrong with my Dusters front end?

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Dusterfreak

Dusterfreak

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Hi, I have a -71 Duster with a -73up front end. Spindels, brakes, pitman arm, steering box (power steering) centerlink... everything else but control arms are from a late A-Body. Problem is that the car is acting strange, its hard to explain but its almost dangerous to drive. Feels like theres something loose, but everything is in place and all bushings and joints are new. Steering is very fast, again turning circle is quite large... What did I do wrong??
 
Dusterfreak said:
Hi, I have a -71 Duster with a -73up front end. Spindels, brakes, pitman arm, steering box (power steering) centerlink... everything else but control arms are from a late A-Body. Problem is that the car is acting strange, its hard to explain but its almost dangerous to drive. Feels like theres something loose, but everything is in place and all bushings and joints are new. Steering is very fast, again turning circle is quite large... What did I do wrong??
Click to expand...
Center link may be upside down
 
Get "one of you" under the car so someone can turn the wheel in various ways back and forth, looking for movement that should NOT be there as well as movement that is NOT there that should be

What are you using for tires?

What did you use for alignment specs?

Start with the steering coupler. Gently wiggle the wheel back and forth, looking for UNWANTED relative movement between the steering column shaft and the coupler, as well as between coupler and box shaft

Look for LACK of movement at pitman arm as wheel is wiggled.

Go on down the system step by step from there

Don't assume anything. Broken / cracked K member or A arms, etc

Tires and alignment make a TREMENDOUS difference.
 
Drum brakes, or did you put on 73 disk spindles without changing the UCA?
 
Tires are 195/60/15 because late spindels and a huge -offset brought tires close to the fender. I dont know about alignment specs but the guy who did it did a great job with my -64 Valiant and my brothers -68 barracuda. And the Duster runs great too, until you turn the wheels in higher speeds... Example: Im passing a slower car at 80km/h, when im on the left lane I have to turn steering wheel to the right to go forward, and again when Im back at the right lane I have to turn steering wheel to get the car straight... :banghead:
Edit: Disc brakes and Upper Control Arm with small joint. Theres a sleeve to shim the small joint to the spindle.
 
Now that I think about it, I did assemble the spindels "backwards", to get the calibers on the rear side of the spindels. Is that the PROBLEM??
 
Sounds like not enough caster to me if you have an issue at higher speeds. Are the tires wearing even?
 
How many degrees of positive caster when you did the alignment?
 

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Dusterfreak said:
Now that I think about it, I did assemble the spindels "backwards", to get the calibers on the rear side of the spindels. Is that the PROBLEM??
Click to expand...

No. Spindles can be switched side for side as long as you switch the calipers too (so the bleeders remain on the top).

So, let me get this straight- if you turn the car to the right, it will keep turning right unless you manually turn it left to recenter it? Does it do that in both directions?

It could be the adjustment on the steering box. It should want to re-center itself, if its "sticking" it could need to be re-centered. Or the steering box could just be worn out. I'd still check the pitman, idler, tie rods etc to make sure nothing was loose or broken. You should also check the steering box mount on the K frame, they have been known to crack at the welds, and then the mount flexes back and forth so the steering box moves when you turn the wheel.
 
^Yes, thats exactly what it does.Would these make any difference to the alignment: http://www.magnumforceracing.com/st...BrandID=&Category=&SubCategory=&Search=&Page=
The car is totally rebuilt in past few years and the K-member was ok when I sandblasted and painted it. Box was supposed to be rebuilt when I bought it. Coupler and idler arm are the only parts I didnt swap new, they came second hand.
Badart: I dont remember degrees, but I dont belive it all comes from the alignment. Theres got to be something wrong/ broken...
 
The tubular control arms have additional caster built into their design, which is a good thing. They should make it easier to get a proper, modern spec alignment.

If the steering box was rebuilt and this is the first time its been run its VERY possible that it needs to be re-centered. Somewhere on here there's a detailed thread about how to do that, its not all that difficult, but I'd have to look up how to do it myself as I haven't had the pleasure.

At some point you should also find out what the actual numbers are on your alignment as well. If its been aligned to factory specs you're doing yourself a disservice, those specs were intended for bias-plys. #-o Something in the range of -.5* camber, +4* caster and around 1/16" toe in is where you should be.
 
In my experience, the issue of a car not returning to straight when turned is a lack of toe in. 0º toe in will reduce tire wear and initial steering effort to turn. It's a question of what you're willing to trade off.

Factory settings for the 71 Duster are:
Toe in 3/32 - 5/32 inch
Camber LH 0º 15' - 0º 45' positive
RH 0º 0' - 0º 30' positive
Caster 0º 15' to 1º 15" positive

Bear in mind these cars were originally built with bias ply tires. Radial tires respond a bit differently. Here are the settings I use on the Darts.

Toe in 1/16"
Camber 1º 30' both sides
Caster 2.5º positive (all that either chassis would allow)

Both cars have 60 series radial tires on 7" rims and power steering. Steering effort is slightly higher, turn-in much sharper than the older settings. Recommend setting ride height before adjusting suspension.
 
My next guess was gonna be not enough caster, but I see it's already been suggested.

I'm out of ideas. Good luck.
 
2 Darts said:
In my experience, the issue of a car not returning to straight when turned is a lack of toe in. 0º toe in will reduce tire wear and initial steering effort to turn. It's a question of what you're willing to trade off.

Factory settings for the 71 Duster are:
Toe in 3/32 - 5/32 inch
Camber LH 0º 15' - 0º 45' positive
RH 0º 0' - 0º 30' positive
Caster 0º 15' to 1º 15" positive

Bear in mind these cars were originally built with bias ply tires. Radial tires respond a bit differently. Here are the settings I use on the Darts.

Toe in 1/16"
Camber 1º 30' both sides
Caster 2.5º positive (all that either chassis would allow)

Both cars have 60 series radial tires on 7" rims and power steering. Steering effort is slightly higher, turn-in much sharper than the older settings. Recommend setting ride height before adjusting suspension.
Click to expand...


A static setting of 0 toe in will give you toe out while in motion. The rolling wheels tend to pull all of the slack out of the steering components, so while the car is rolling the wheels will tend to toe out slightly. A small amount of toe in corrects this, the end goal of a little toe in is 0 toe while the car is motion.

Positive camber is for bias plys. Period. If you're running radials with positive camber you're not doing yourself or your tires any favors. And 1* of camber in either direction is pretty close to causing premature wear on the edges of your tires. I know this because I've run up to -1.5* camber on the street, on both modern and classic mopars.

Look at the alignment specs for modern cars. All run negative camber. It has nothing to do with the suspension, the suspension doesn't care. Its all about tire wear and traction. If you run modern tires, you should use modern alignment specifications. The Skosh chart below is an excellent reference. It's a little conservative on caster, it was probably intended for manual steering cars. With power steering +4* caster isn't an issue, although on a manual car that much will make the steering effort a bit higher. You'll need offset bushings or tubular arms to get that much caster though.
 

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Same guy adjusted my bros -68 barracuda and that car runs great, corners well and runs like a train on a highway. He has original steering and suspension except poly bushings. Thats why I was wondering if I did something wrong... Are lower control arms the same -67-72 and -73up??
 
Dusterfreak said:
Feels like theres something loose
Click to expand...
And this is the moment I feel like a moron... :sign3:
Steering box bolts were loose, bolts that I doublechecked!!
I have driven the car for 800km and I think that the problem was there all the time, thats why I thought something went wrong on the built. I bought tubular control arms and I will buy drop spindels also during winter... lets see how it corners next summer.
 
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