Front A body suspension help please

Discussion in 'Suspension, Steering and Chassis' started by Steve Agrella, Oct 22, 2018.

  1. Steve Agrella

    Steve Agrella FABO Gold Member FABO Gold Member

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    I'm pretty new to a Mopar cars I recently purchased a 1974 360 Duster with a boat like washy front end feel especially under hard acceleration.
    I want to firm up the front end to get rid of the mushy feel, I have Cooper Cobra 225-60R-15 on the front 275-60R-15 on the rear, stock Torsion bars and KYB shocks that look pretty new, this is what came on the car when I purchased it.
    All of the suspension parts have Been replaced including upper and lower ball joints, control arm bushings, tie rods etc.
    Any suggestions without breaking the bank to firms things up, it’s a street car so don’t want super stiff front end.
    Oh! I purchased a Helwig 11/8 sway bar however it has not been installed yet.
     
  2. 72bluNblu

    72bluNblu FABO Gold Member FABO Gold Member

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    Replace the stock torsion bars with PST 1.03” bars, throw the KYB’s in the trash and buy a set of Bilstein RCD’s, and make sure you have an alignment set up for radials (not the stock alignment specs). And mount that sway bar.
     
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    • MileHighDart

      MileHighDart FABO Gold Member FABO Gold Member

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      does it have a front sway bar now?
       
    • La-Motor

      La-Motor FABO Gold Member FABO Gold Member

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      Ride quality is really a personal preference. My suggestion is to start with the front sway bar and stop when you reach a point where you're happy. You will also want to install a rear sway bar to balance the front. if you don't, the rear end will want to step out on you during hard cornering. The KYB shocks are not great but they're decent...sure there are better ones to be had, but if you're on a budget and they're not shot, then there's no need to replace them yet. I also bought the PST 1.03 torsion bars to replace my /6 bars and never installed them because after installing the front and rear sway bars, I was really happy with the ride quality...it corners very well and is not too harsh over rough roads.
       
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      • TrailBeast

        TrailBeast Slightly Twisted Member

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        I have to agree on the larger torsion bars and the sway bar install.
        If those KYB's are the monotube style they work ok for stiffening things up a little.

        I run the 1.03 bars with the KYB monotube and it made a huge difference, but you can make your own decision on shocks when you look at some of the prices.:D
        I'm sure some of them are fantastic, but gees.
        The KYB mono's cut down on the front end dive a lot that helped with the really crappy streets we have.
         
      • Frnknsteen

        Frnknsteen FABO Gold Member FABO Gold Member

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        I agree with Blu, but have a couple quick questions....

        1. Sounds like you replaced the bushings, balljoints and tie rods,.... What about the Pitman arm and Idler arm?
        2. What size torsion bars are in there? I ask because mine were still the stock /6 bars (Previous owner didn't change them when swapping to 400, and they were cranked all the way up just to keep the front end up). It was scary to drive.
        3. Is your steering coupler, between the steering column and the steering box, good and tight (Not a lot of play in the wheel)?
        4. Big point in what Blu said,... is it aligned properly for radial tires? What are the Camber, Caster, and Toe settings?

        I ask because I had the same washy feeling to my Barracuda. Better after replacing everything, but still wanted to wander. My final issues were the steering coupler installed incorrectly (Meaning the little blocks in there were installed the wrong direction so there was excess slop) and poor alignment. Mine was hard to control, especially under hard acceleration. Once I got everything back in correctly, it handled much better, but still wandered all over the place until I got it aligned properly. Scary driving to the alignment shop, nice to drive coming home from shop.

        Other than that,... I agree completely with Blu. I'm running 1" Firm Feel torsion bars and Bilstein RCD shocks. It's a little stiff, and you can feel it on rough back roads, but out on the highway it rides nice and handles well. I also added a 1 1/8" Firm Feel anti-sway bar. I noticed a little improvement, but not a lot unless driving it hard.
         
      • 72bluNblu

        72bluNblu FABO Gold Member FABO Gold Member

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        The Bilstein RCD's are worth every penny.

        I ran KYB monotube "gas adjust" shocks in my Challenger with 1.12" torsion bars on the street for over 60k miles. Now, keep in mind that 1.12" E-body bars are longer so the wheel rate is lower than an A-body bar with the same diameter. 1.12" E-body bars are ~270 lb/in, the 1.03" PST A-body bars are 230 lb/in. Plus the car is heavier than most A's. Anyway, the car rode stiff, but I just attributed it to the large torsion bars. I finally swapped the KYB's out for a set of Bilstein RCD's, and I instantly regretted ever using the KYB's. It's a HUGE difference, the KYB's are awful. The difference between the Bilsteins and the KYB's is night and day. I wouldn't put them on anything ever again, I don't care if KYB sponsored me and sent me a lifetime supply of those hunks of crap, I'd toss all of them.

        Also, the Hotchkis Fox shocks are a little better than the Bilstein RCD's. Probably not worth the extra cost with a set of 1.03" bars, but I did notice the difference going from the RCD's to the Hotchkis shocks on my Duster with 1.12" bars (300 lb/in wheel rate). The Duster rides nicer than the Challenger ever did with the KYB's, even being a lighter car with a higher wheel rate. Once you go past 1" torsion bars you need to have a set of shocks intended for the kind of wheel rates they have. The damping the shocks provide has to be matched to the wheel rate the springs give. The better the match, the better the ride.
         
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        • RBConvert

          RBConvert Well-Known Member

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          if all the wearable parts were replaced I'm surprised the front end feels "mushy". Don't have any experience with KYB's but I'm running Bilsteins on both cars and they are great shocks. If you can find it in your budget I recommend swapping out the KYB's. As mentioned, measure your T-bars; they may be the /6 .83". My Dart has .92's with a 360 and the Coronet has .96's with a 440; neither has sway bars and they handle great.

          If the wishy-washy feel is in the steering then think about having Firm Feel rebuild the steering box. They rebuilt the man box in the Dart and a Stage III p/s rebuild in the Coronet. Huge difference in the steering feel.
           
        • Steve Agrella

          Steve Agrella FABO Gold Member FABO Gold Member

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          Thanks so much for all of the replie, going to put the sway bar on and pick up a pair of the Bilstiens
           
        • AJ/FormS

          AJ/FormS 367 FormS clone 3.09-1.92-1.40-1.09-.78od 3.55s

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          Before you spend all that money on shocks, have you tried putting some air in those tall-boy tires, and lowered the front ride height a lil? What about the rear tire pressure? The quickest way to make her mushy is to run soft springs in the back and 20psi, you'll be chasing her all over the road, worse if the front end is surfing
           
        • PST

          PST Marketing Manager FABO Vendor

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          As the 7 posts above suggested the best bang for the buck would be the 1.03" torsion bars and Bilsteins and an updated alignment. As a member of the forum you are eligible for 10% off order of $200 or more and free shipping within the USA 48 states.

          A Bodies Only Member's Discount

          Thanks
          James From
          PST Marketing
           
        • jedrattle

          jedrattle Well-Known Member

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          Thank you for that!

          I'm reading this thread because I just my 64 Valiant running and driving. It drives horrible!! Very rough, I feel every bump in the road through the floor. I had the alignment done and they sucked at it. It's all over the road. I need to replace the older arm and the pitman arm. I replaced the front part of the strut rod bushings but not the rear because you have to drop the lower arm. So next week I'm going to drop the lower arm and replace the strut rod bushings and the lower arm bushing as well. Since I'm in there, I'm going to upgrade to 1.03 bars. I found a shop to do the alignment that knows what they're doing. Hopefully that fixes everything and I can start driving it
           
        • AJ/FormS

          AJ/FormS 367 FormS clone 3.09-1.92-1.40-1.09-.78od 3.55s

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          The 1.03 bar is not gonna make it any less rough
          You got radials on it? Then start by lowering the tire pressures. Try down to 28 front and a pound or two less in the back. But if not radials, then get some. Whatever non-radial you might have is likely old, hard, and risky business cuz they have been out of production for going on 50 years.
          If nice new radials at 28psi don't do it,
          then, if you have adjustable front shocks; set them on full soft.
          If not-adjustable, then take the front shocks off.
          Either way; roadtest it, just keep the speed down, cuz things can get wild in a hurry.
          Make sure your seat has some spring to it,lol. And there shoulda been some under-pad installed before the carpet went on.
          Try that and Good-Luck
           
          Last edited: Oct 24, 2018
        • RBConvert

          RBConvert Well-Known Member

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          I agree with AJ that 1.03 T-bars shouldn't be your first choice. I know a lot of guys love the feel of the big bars, but if your Valiant is a /6 daily driver you don't need 'em. Replacing the wearable components of your suspension and steering and upgrading to the Bilsteins will give you a nice ride.
          The alignment is critical too. As mentioned up top the alignment has to fit today's radial tires; don't go by the OEM specs. Go to moparaction.com and search for 'skosh chart'. The chart gives alignment specs designed around radial tires and more aggressive driving habits. Lastly, make certain the alignment shop understands how to align t-bar suspensions. Print out the skosh chart for them to reference and then have them print out the caster/camber/toe-in specs after they're done.
           
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          • RBConvert

            RBConvert Well-Known Member

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          • 72bluNblu

            72bluNblu FABO Gold Member FABO Gold Member

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            $10 says you're riding on the bump stops. Even the V8 torsion bars you should have with that 273 car are small. If they're original they've sagged, and if the ride height is anything less than stock you'll be constantly bottoming the suspension out. That's why the ride is horrible, you're bouncing the control arms off the frame with any large bump in the road.

            Replace all the worn out bushings. Check to make sure the K frame is solid, the LCA pivot tubes are known to break free in the K member so rule that out while you've got it apart. If you've been riding around on the bump stops for awhile you should inspect everything to make sure nothing is cracked or broken. With new bushings, a proper alignment, and the 1.03" torsion bars you shouldn't bottom out the suspension as long as you don't set the ride height too low. With the 1.03" bars you can go lower than factory but you may need a shorter lower bump stop. As I mentioned before you'll want a good set of shocks with the 1.03" bars, none of the old shocks are set up to handle the higher wheel rates of the larger bars.

            attachment-jpg.jpg

            Uh, first off he has a 273, so it's not a /6 car.

            And actually, the 1.03" bars might make the ride less rough. Because more than likely the ride is rough because he's bottoming the suspension out all the time. Which means the larger bars might actually help solve that problem, not make it worse.

            I daily drive my Duster with 1.12" bars. If you don't want your car to handle like a 70's land yacht, you need torsion bars larger than 1". The 1.03" bars are the smallest I'd ever go, I ran 1" bars for awhile and was still totally underwhelmed with the handling of the car. And that was just with 225/60/15's on it, nothing fancy.
             
            Last edited: Oct 24, 2018
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            • AJ/FormS

              AJ/FormS 367 FormS clone 3.09-1.92-1.40-1.09-.78od 3.55s

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              yeah what Blu said;possibly on the bumpstops.
               
            • jedrattle

              jedrattle Well-Known Member

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              Thanks for the responses! It's the car in my avatar. 235/45/17 front tires. I have the printout of the specs they did at home. I adjusted the torisons to a 25in fender opening height. After the alignment it sat gasser style. The front had raised up to 29.5! It was all over the place. I've lower it down to 24.75 but it settled some more. It's still over the road. I can see the top of the tire is laid in and the toe is out. So that is making it drive so crappy. It's very close to the bumpstop. So I image it's hitting constantly. It has KYB's on it. I'm going to put the torisons in ASAP. The Bilstiens will have to wait a little bit. I'll give the alignment shop that list and tell them that's what I want. I think I'll go with the max street performance specs (I drive it like I stole it! Lol)

              What bumpstop stops? I don't want those short hard poly ones.
               
            • AJ/FormS

              AJ/FormS 367 FormS clone 3.09-1.92-1.40-1.09-.78od 3.55s

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              Yes you do. But you gotta get the ride height figured out first. And once you do, then if you change it, you will need a new alignment.
              And I would either take it back to that earlier shop and tell them not to change your height cuz the obviously don't know chit about how to do that, and I would demand a free "adjustment", or I would just never go back there.
              The reason you want the polys is cuz when you stuff your baby into a corner really hot, the chassis will settle on the stop, and then try to lift the other wheel off the ground, which with a 273 would likely be the first time ever,lol. But while it's trying to, it will corner like it's on rails,literally. Until you hit a bump or a hole, lol.
              If you upgrade the T-bars, then at proper ride-height you will have a really hard time hitting the stops, and if your 235s have trouble sticking to the road, then you will be sliding long before you get on the stops; So, IMO it doesn't much matter what your stops are made of.
              Before you go to the alignment shop, you need to set the car level from side to side, front and rear. This starts with rear springs. If one is soft, it will mess you up.
               
            • jedrattle

              jedrattle Well-Known Member

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              Ok that makes sense. As far as lifting a wheel...you've never seen me drive!! Lol
              That little 273/4spd combo moves pretty good for what it is. I have the poly stops in the garage. I'll install them when I change bushings
               
            • RBConvert

              RBConvert Well-Known Member

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              Yep, didn't notice his signature line; that's also why I prefaced by reply with 'if'. And I get that a lot of owners like the bigger bars for all the reasons mentioned. When I rebuilt the Dart's front end I kept the .92's because they were less than 10 years old and there were wearable parts that needed replacing. But the biggest enjoyment bang-for-the-buck was having the steering box rebuilt. Went from almost 1/4 turn play in the steering wheel down to almost none.
               
            • Duane

              Duane Well-Known Member

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              Make sure to put in some poly urethane strut rod bushing.
              These will make your toe in setting stay toed in and make the car go straight. The rubber ones are too soft.
               
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              • 72bluNblu

                72bluNblu FABO Gold Member FABO Gold Member

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                The rubber ones are too soft when it comes to front to rear shift, they allow the LCA's to shift forward and rearward under braking and acceleration. The poly ones are great for that, the stiffer compound keeps the LCA from moving forward or back. But the poly bushings are also stiffer in the up/down travel, which isn't good. It adds resistance to the LCA when it's traveling up and down, and that keeps the suspension from moving freely.

                Best bet for strut rods in my opinion is the adjustable ones that are available. You get to tailor the length to match your car's suspension so there's no binding, and they're basically solid when it comes to forward/rearward motion of the LCA. But the pivot freely up and down. Most of the poly strut rod bushings are also the wrong thickness, so if you use them with stock strut rods you're likely to have the strut rods be the wrong effective length, which will cause binding in the LCA.
                 
              • Duane

                Duane Well-Known Member

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                I have the hemi joint type on my drag car, but I do not know that I would use them on a street car. Other than that I said what you said.
                Urethane strut bushings keep the wheels straight.
                A street car does not need that much suspension travel.
                All the rubber bushings everywhere in the front suspension limit travel, not just the strut rod ones.
                 
              • Kern Dog

                Kern Dog Well-Known Member

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                In stock , "As delivered" form, that car should have a factory front sway bar approx 7/8" diameter, .87 Torsion bars and front disc brakes as part of the "Duster 360" package.