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#2532674 - 08/07/18 07:33 AM Sorting out suspension...could use some advice (as always!)
MRGTX Offline
member

Registered: 11/17/13
Posts: 86
Loc: Connecticut, USA
I've talked about my suspension mods a lot but so far, I'm not really happy with how it drives yet. I realize that I have more parts to buy, more tuning and more work ahead but this is where my car is right now and I would love some advice on where to go next.

'73 Dart Sport, original 318 car (Magnum 5.9 swap)
8 3/4" rear with 4.10 Eaton TrueTrac
Built A904 (until I can afford the T56 conversion)
Non-power brakes
Stock front disks Ford Explorer rear disks
Manual 16:1 steering with Tuff Wheel replica
Aluminum wheels 15x8 +0mm rear and 15x7 +10mm front
255/60/15 rear Radial T/As (ugh)
225/60/15 front Radial T/As (ugh).
Stock front sway bar, no rear sway bar
QA1 Upper and Lower control arms
Sway-A-Way 1.14" torsion bars
Hotchkis lowering leaf springs
Fox 1.5 shocks (Hotchkis)
Mancini Camber spacers

Don't get me wrong, I LOVE driving it...but in general it feels like it needs a lot of work before it drives anything like I had hoped.

A few specific points of concern:

1)Brand new (re-man) steering box but there's still a ton of play (20*-30*?) in the steering and it really spoils the driving experience.

2) Alignment...I'm still trying to figure out what else I need to replace to fix the awful steering action and I'm trying to decide on a ride height so I'm hesitant to pay for a professional alignment just yet but I've made a lot of adjustments to camber and toe just playing around with it and it tracks nice and straight though I'm sure it's far from optimized for handling.

3)Something's not right in the rear end. The springs seem way too stiff. I know the Hotchkis springs are much heavier than stock but it feels really rigid when I push down on the bumper and a couple of times it has really gotten jittery over bumps in a way that spooked me.

4)Something else weird with the rear- the car is straight, never hit, everything looks to be lined up correctly yet the driver's side sits slightly higher in the rear than the passenger side. Could this be related to the shackles binding? I just don't know what else could cause this...

5) Something's just weird with the feel on turn-in. It's really hard for me to explain it but it's like the chassis settles in the wrong direction when loading up on a curve.

I'm far from giving up...I just know that a properly set-up Mopar can be a great handling and satisfying car to drive...I'm mostly flailing around in the dark though AutoXCuda and 72BlunBlu (over on the Abodies forum) have helped a ton already through their threads as well as direct answers.

Any thoughts, advice, appropriately phrased insults, etc. are welcome. smile

I don’t have much footage of the car in action but when watching this quick clip, Something looks odd...Is there something weird about how the front end moves here? I know...not much to go on but it almost looks like there's no suspension travel at all?

https://youtu.be/76aQKC2U7zc





Edited by MRGTX (08/07/18 07:44 AM)

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#2532696 - 08/07/18 08:30 AM Re: Sorting out suspension...could use some advice (as always!) [Re: MRGTX]
Supercuda Offline
I Live Here

Registered: 09/04/07
Posts: 13407
There are two philosophies in regards to spring rate.

Stiff with no or little sway bars. Makes for jittery rides on less than smooth pavement.

Softer springs with big swaybars. my preferred setup.

Adjust the freeplay in your steering box, procedure is in the FSM.

Odds are most of your handling issues are due to lack of alignment. What are your current specs?

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#2532698 - 08/07/18 08:37 AM Re: Sorting out suspension...could use some advice (as always!) [Re: Supercuda]
MRGTX Offline
member

Registered: 11/17/13
Posts: 86
Loc: Connecticut, USA
Thanks, Supercuda.
I may be in for the stiff springs already...so maybe upgraded sway bars wouldn't be useful at this point?

I'll check out the free play adjustment. Thanks!

As for alignment specs. They're set at exactly "that looks about right." Yeah, I know, it's not scientific. I've been playing around with it to the point where it has just enough negative camber to be visible to a careful look and I've tinkered with the toe adjustments until the tracked straight. I really imagine (and hope) that there is a lot of improvement to be had with a performance alignment.

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#2532860 - 08/07/18 02:36 PM Re: Sorting out suspension...could use some advice (as always!) [Re: MRGTX]
BigBlockMopar Offline
master

Registered: 01/22/03
Posts: 3347
Loc: The Netherlands
I gather you haven't touched the caster-settings yet?
That's where the most of the proper handling/tracking/stability will come from.
Simply eye-balling the alignment is simply impossible and certainly no option to achieve any proper handling.

Steeringplay, I would assume that a "remanufactured" box would have the play taken care off.
If the rest of the steering linkage is good and tight, my guess is the box just received some new gaskets and grease inside.
Are you really sure the box is mounted tight on the K-member? (Have someone steer left/right while you observe possible box movements.)
How tight is the steering coupler?

Most often the idler-arm bushing is the cause for lousy or vague steering response. Next to that are loose steering boxes, worn/trashed LCA bushings, worn ball joints or loose wheel bearings.

A good alignment shop shouldn't even start the alignment-job until these parts are replaced and play-free.

As for nr. 4 and 5;
(4) Torsion bars are pre-loaded unevenly.

(5) Caster setting way off, or bushings trashed?
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#2532863 - 08/07/18 02:39 PM Re: Sorting out suspension...could use some advice (as always!) [Re: MRGTX]
BigBlockMopar Offline
master

Registered: 01/22/03
Posts: 3347
Loc: The Netherlands
Why do the front wheels have +10mm offset?
Is that to the inside or outside?
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#2533064 - 08/07/18 09:05 PM Re: Sorting out suspension...could use some advice (as always!) [Re: BigBlockMopar]
Skeptic Offline
master

Registered: 01/20/03
Posts: 4245
Loc: The Pale Blue Dot
The steering is never going to feel like a modern rack steering system, you can maximize it, but it is a systematic thing. So you need to check EVERYTHING one after the other and optimize it. Only check with a load on the tires- on the ground or an alignment rack. The steering column bearings, the coupler, correctly adjust the box, make sure the box is properly tightened, watch the box for k-member flex, it's very common. Make sure the steering arms are tight, wheel bearings properly adjusted and then suspension- i.e. ball joints and bushings are tight.___
The torsion bars and rear springs look like a good match.
You need to get a good professional alignment, have the car checked on a frame rack and have the rear checked for squareness. The factory tolerances are really pathetic on the frame and needing shims to square up the rear end is common- you'll note that several companies make them for old Mopars. work___
After all this, you can play with the shock adjustments.___

If you are O.K. with the body roll after all this, you are golden, if not I'd go with Firm Feel or Helwig bars. This is just my personal preference, Hotchkis and PST both make good product as well.___

The tires will then be the limit and those old T/As just won't get it done. twocents wave
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#2533190 - 08/08/18 08:44 AM Re: Sorting out suspension...could use some advice (as always!) [Re: Skeptic]
MRGTX Offline
member

Registered: 11/17/13
Posts: 86
Loc: Connecticut, USA
Originally Posted By BigBlockMopar
I gather you haven't touched the caster-settings yet?
That's where the most of the proper handling/tracking/stability will come from.
Simply eye-balling the alignment is simply impossible and certainly no option to achieve any proper handling.

Steeringplay, I would assume that a "remanufactured" box would have the play taken care off.
If the rest of the steering linkage is good and tight, my guess is the box just received some new gaskets and grease inside.
Are you really sure the box is mounted tight on the K-member? (Have someone steer left/right while you observe possible box movements.)
How tight is the steering coupler?

Most often the idler-arm bushing is the cause for lousy or vague steering response. Next to that are loose steering boxes, worn/trashed LCA bushings, worn ball joints or loose wheel bearings.

A good alignment shop shouldn't even start the alignment-job until these parts are replaced and play-free.

As for nr. 4 and 5;
(4) Torsion bars are pre-loaded unevenly.

(5) Caster setting way off, or bushings trashed?


Great info here! Thank you.

The idler arm bushings that you mentioned may be a critical point...this is one of the few components that hasn't been replaced yet. That will be my next step! Thanks. Looks like they're ~$100 from Mancini. Would anyone recommend a different source?

That's a really interesting question about the steering coupler...can they be loose? IIRC, they're splined, no? I used an extension coupler from Mancini when swapping to the manual box. This is worth a look. I will also re-torque the bolts holding in the box.


Originally Posted By BigBlockMopar
Why do the front wheels have +10mm offset?
Is that to the inside or outside?


The +10mm moves the wheels in-board a bit as it moves the mounting pad 10mm closer to the outside rim of the wheel. A-Bodies are known to have a narrower track in the rear and I wanted to reduce that a bit, even if it's only 20mm over all.

My wheels are a complicated question as the front wheels started out as 15x8+10 but they didn't clear the upper control arm so I had a shop narrow them (because they didn't make these wheels in 15x7 and I love to throw good money after bad smile ).


Originally Posted By Skeptic
The steering is never going to feel like a modern rack steering system, you can maximize it, but it is a systematic thing. So you need to check EVERYTHING one after the other and optimize it. Only check with a load on the tires- on the ground or an alignment rack. The steering column bearings, the coupler, correctly adjust the box, make sure the box is properly tightened, watch the box for k-member flex, it's very common. Make sure the steering arms are tight, wheel bearings properly adjusted and then suspension- i.e. ball joints and bushings are tight.___
The torsion bars and rear springs look like a good match.
You need to get a good professional alignment, have the car checked on a frame rack and have the rear checked for squareness. The factory tolerances are really pathetic on the frame and needing shims to square up the rear end is common- you'll note that several companies make them for old Mopars. work___
After all this, you can play with the shock adjustments.___

If you are O.K. with the body roll after all this, you are golden, if not I'd go with Firm Feel or Helwig bars. This is just my personal preference, Hotchkis and PST both make good product as well.___

The tires will then be the limit and those old T/As just won't get it done. twocents wave


Point taken on the comparison to modern steering. I think my expectations are realistic and I know there will always be a relative lack of precision and road feel. I just would like a whole lot less play. You've provided a good roadmap on how to go through the system. Thanks.

I'll look into the shims for the springs. The car sat even (to my eye) on the original springs...but maybe the stiffer springs are exacerbating a tolerance issue?

Tires- Yeah, I've long noticed how poor the T/As are by modern standards but as we have talked about in this forum, there aren't really any superior options in the 15"/60 series range. What would you recommend.


Edited by MRGTX (08/08/18 08:45 AM)

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#2533264 - 08/08/18 11:26 AM Re: Sorting out suspension...could use some advice (as always!) [Re: MRGTX]
TC@HP2 Offline
master

Registered: 01/23/03
Posts: 4855
Loc: Pikes Peak Country
Originally Posted By MRGTX
I've talked about my suspension mods a lot but so far, I'm not really happy with how it drives yet. I realize that I have more parts to buy, more tuning and more work ahead but this is where my car is right now and I would love some advice on where to go next.

'73 Dart Sport, original 318 car (Magnum 5.9 swap)
8 3/4" rear with 4.10 Eaton TrueTrac
Built A904 (until I can afford the T56 conversion)
Non-power brakes
Stock front disks Ford Explorer rear disks
Manual 16:1 steering with Tuff Wheel replica
Aluminum wheels 15x8 +0mm rear and 15x7 +10mm front
255/60/15 rear Radial T/As (ugh)
225/60/15 front Radial T/As (ugh).
Stock front sway bar, no rear sway bar
QA1 Upper and Lower control arms
Sway-A-Way 1.14" torsion bars
Hotchkis lowering leaf springs
Fox 1.5 shocks (Hotchkis)
Mancini Camber spacers

Don't get me wrong, I LOVE driving it...but in general it feels like it needs a lot of work before it drives anything like I had hoped.

A few specific points of concern:

1)Brand new (re-man) steering box but there's still a ton of play (20*-30*?) in the steering and it really spoils the driving experience.


Most reman boxes are not remanufactured so much as simply dis-assembled, inspected, excessively worn parts replaced, new gaskets installed, and put back together. Short of a new boxes, all reman boxes will be like this. Adjust freeplay as suggested earlier and see if that tightens things up a bit. The Borgeson unit may be the best example of a recirculating ball box out there. They are newer, have tighter tolerances, and an improved feel.

Originally Posted By MRGTX

2) Alignment...I'm still trying to figure out what else I need to replace to fix the awful steering action and I'm trying to decide on a ride height so I'm hesitant to pay for a professional alignment just yet but I've made a lot of adjustments to camber and toe just playing around with it and it tracks nice and straight though I'm sure it's far from optimized for handling.


Are you using a gauge at all or just a string/tape measure? Garage alignments are only as good as the effort you put into them and you can do the basic as well as thrust measurements, but will lack some precision. You are right that you need height decided before you dial in alignment. You didn't mention it but I'd suggest setting max caster first (rear eccentric bolt all the way in/front all the way out), then adjust for camber, finally toe. You can map out the position of everything on your garage floor with a plumb bob and measure it to see how everything lays out squarely, but it takes some effort. While never being an an accident is good news, the factory specs from this era were pretty loose and its possible for any position to be up to an eighth out of ideal. Stack them all up and things can be off quite a bit. Same with a rear thrust measurement. Possible, but takes an effort to be as accurate as possible.

Originally Posted By MRGTX

3)Something's not right in the rear end. The springs seem way too stiff. I know the Hotchkis springs are much heavier than stock but it feels really rigid when I push down on the bumper and a couple of times it has really gotten jittery over bumps in a way that spooked me.


Pushing down on the back won't tell you much. You've got maybe a couple hundred pounds of force. The car will be exerting a couple thousand pounds of force. If it feels jittery over bumps, try softening the shock setting. You could also put it up in the air and move it through its motion to make sure it isn't binding since that was mentioned below.

Originally Posted By MRGTX

4)Something else weird with the rear- the car is straight, never hit, everything looks to be lined up correctly yet the driver's side sits slightly higher in the rear than the passenger side. Could this be related to the shackles binding? I just don't know what else could cause this...


T-bar adjustment height will impact rear height. If you are adjusting both front bars to be exact, it can throw off height in the rear. Adjust the passenger front up slightly to correct.

Originally Posted By MRGTX

5) Something's just weird with the feel on turn-in. It's really hard for me to explain it but it's like the chassis settles in the wrong direction when loading up on a curve.


Could be weight jacking (or lack of) from the caster setting. Is this a low, medium, highspeed, left, right, both directions, does it take more or less effort one way or the other. Lots of things to dig into with this.

Originally Posted By MRGTX

I'm far from giving up...I just know that a properly set-up Mopar can be a great handling and satisfying car to drive...I'm mostly flailing around in the dark though AutoXCuda and 72BlunBlu (over on the Abodies forum) have helped a ton already through their threads as well as direct answers.

Any thoughts, advice, appropriately phrased insults, etc. are welcome. smile

I don’t have much footage of the car in action but when watching this quick clip, Something looks odd...Is there something weird about how the front end moves here? I know...not much to go on but it almost looks like there's no suspension travel at all?

https://youtu.be/76aQKC2U7zc


Can't see your hand in relation to the car's direction. It looks like a semi-abrupt turn. Maybe turning the wheel some before the tires catch up. Might have someone turn the steering wheel while you watch the steering box and linkage. As suggested by others, box mounting flex in the K frame as well as tolerance stack up from other components could all be factors in the turn in feel.

Overall combo seems like a good starting point. May be light on front sway bar. If you can find a large, empty parking lot, you can try some skid pad exercises to find out your suspension balance. walk out a 100' diameter circle, drive the circle 5 times left, 5 times right at increasing speed until you feel the front or rear of the car slide and you balance will become obvious. The car feels the combined difference between front and rear rates in both the springs and sway bars. Because of the front engine layout, you want more rate up front to handle the weight. The skid pad circle exercise will tell you which end needs more or less rate.

Yes, steering couplers wear. There are a couple of shoes inside them as well as the housing its self. There are rebuild kits out there for them. Also, if you have an adapter, that is another joint added to the system which can contribute to tolerance stack up.

Yea, TAs are not the best choice. If you want to stick with 15s try the MT SR. Its one of the newest 15" carcass designs out there, easily available, reasonably priced, with a relatively soft compound. Might also try stepping up front sizes as the narrower front tire will tend to understeer.

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#2533395 - 08/08/18 03:57 PM Re: Sorting out suspension...could use some advice (as always!) [Re: MRGTX]
BigBlockMopar Offline
master

Registered: 01/22/03
Posts: 3347
Loc: The Netherlands
Idler arm bushings priced at $100 should be roller bearinged.
FirmFeel has these too.

A competent person with a lathe could turn 2 halves out of nylon/delrin and have a similar sturdy design made up.


I converted the stock disbrakes on my own '73 Dart to beefy C-body 11.75" rotors.
Added 'bonus' was the front track width got narrowed by some 3/8 I recall in the process.
Not sure if the same will happen with b-body 11.75 rotors. Would like to know myself as well too.
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#2533419 - 08/08/18 04:47 PM Re: Sorting out suspension...could use some advice (as always!) [Re: BigBlockMopar]
autoxcuda Offline
Too Many Posts

Registered: 01/20/03
Posts: 25895
Loc: So Cal
Originally Posted By BigBlockMopar
Idler arm bushings priced at $100 should be roller bearinged.
FirmFeel has these too.

A competent person with a lathe could turn 2 halves out of nylon/delrin and have a similar sturdy design made up.


I converted the stock disbrakes on my own '73 Dart to beefy C-body 11.75" rotors.
Added 'bonus' was the front track width got narrowed by some 3/8 I recall in the process.
Not sure if the same will happen with b-body 11.75 rotors. Would like to know myself as well too.



Is firm feel the only source for idler arm roller bearings?
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#2533428 - 08/08/18 05:05 PM Re: Sorting out suspension...could use some advice (as always!) [Re: MRGTX]
BigBlockMopar Offline
master

Registered: 01/22/03
Posts: 3347
Loc: The Netherlands
Perhaps, not sure.

I've seen roller kits on Ebay for older Mopars on occassion, not sure about the '60/'70s stuff.

Just found a rollerbearing conversion kit on some Australian site, but at $130 I'm sure some thinkering in the garage could come up with a cheaper alternative.

I've converted the idler arm bushing on my '57 Chrysler to 2 nylon halves some years back;

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#2533481 - 08/08/18 07:18 PM Re: Sorting out suspension...could use some advice (as always!) [Re: BigBlockMopar]
Skeptic Offline
master

Registered: 01/20/03
Posts: 4245
Loc: The Pale Blue Dot
The Idler Arm roller kit that Firm Feel sells ONLY work with the MOOG idlers, I bought 2 different brands, one I disassembled only to find it wouldn't work. The other was listed somewhat deceptively on E-bay shock -it was NOT a MOOG as listed. I checked that one more carefully and no it wouldn't work either. Even "good" idlers don't hold up very long, I only averaged 6 months of daily driving. I don't have a handle on the longevity or the rollerized one. luck
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#2533604 - 08/09/18 04:35 AM Re: Sorting out suspension...could use some advice (as always!) [Re: MRGTX]
BigBlockMopar Offline
master

Registered: 01/22/03
Posts: 3347
Loc: The Netherlands
The idler-arm on my 73 Dart is holding up real good and I tend to think it has a poly-urethane bushing in it.
I haven't had it apart since I bought the car like this some 7 years ago.
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#2533956 - 08/09/18 07:53 PM Re: Sorting out suspension...could use some advice (as always!) [Re: BigBlockMopar]
Skeptic Offline
master

Registered: 01/20/03
Posts: 4245
Loc: The Pale Blue Dot
[quote]I'll look into the shims for the springs. The car sat even (to my eye) on the original springs...but maybe the stiffer springs are exacerbating a tolerance issue? When my Barracuda had the 185/70-14s it the rearend looked fine, when I put the 255/50-17s the problem was obvious

Tires- Yeah, I've long noticed how poor the T/As are by modern standards but as we have talked about in this forum, there aren't really any superior options in the 15"/60 series range. What would you recommend.
_ 255/50-17s... they are the same dia as your rear tires grin though they are getting harder to find too...or something like this scroll down to the end of the post for pics. If you need/want to stick with 15s, there are the Cooper Cobras or the Mickey Thompson Sportsman S/R Tires or ET Street S/S Tires.


Attachments
DSCF0136.JPG




Edited by Skeptic (08/09/18 08:07 PM)
Edit Reason: more info less snark

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#2534116 - 08/10/18 09:51 AM Re: Sorting out suspension...could use some advice (as always!) [Re: Skeptic]
TC@HP2 Offline
master

Registered: 01/23/03
Posts: 4855
Loc: Pikes Peak Country
Originally Posted By Skeptic
The Idler Arm roller kit that Firm Feel sells ONLY work with the MOOG idlers, I bought 2 different brands, one I disassembled only to find it wouldn't work. The other was listed somewhat deceptively on E-bay shock -it was NOT a MOOG as listed. I checked that one more carefully and no it wouldn't work either. Even "good" idlers don't hold up very long, I only averaged 6 months of daily driving. I don't have a handle on the longevity or the rollerized one. luck


IIRC, Moog used to make and market these bearing kits on the open market a number of years ago. For some reason, I vaguely recall seeing them for sale on some different web sites. Perhaps Firm Feel bought them all up or negotiated a deal with the manufacturer to take all their old stock. These bearing conversions for idler arms are also out there for a number of classics. Obviously Mustang and Camaro versions abound, but they all seem to be in the $80-100 range, even for the belly button cars.

If you really want to put bearings in an idler, I'm sure some minor machine work on an arm and browsing a bearing catalog could net the results desired.

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