Upgrading a Fairly Stock Suspension

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MuuMuu101

MuuMuu101

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So after school's over and winter break starts my friend and I should be able to fix all the safety issues on my 1968 Dodge Dart GT with regards to the steering coupler and brakes. I was thinking my next step on the Dart would be beefing up the suspension a little because it's a bit warn out.

My friend has a pressure washer so the first things first is we're going to clean up the underside of the car of all the grease. A couple of bushings may need attention, (that my friend may already have) so we plan on possibly replacing those as well. My friend and I also plan on fabbing up some sub frame connectors for the car (don't know when or how soon, but he's already done this on his Demon), instead of buying a set.

As far as I can tell, the entire suspension system is stock (no sway bars) except for the air shocks in the back (that don't hold air). The rear leafs are a little saggy (and just look puny). I'm currently running on 14" wheels with 205/75/14 tires; however, I don't want to change those out till I can afford an entire bbp swap. But when I do, I would like 17-18" wheels with 275's all the way around. And lastly, I'd like to stick with a K-frame and leaf springs over the alter-K systems and 4-links (they just cost too much).

I want a car that feels nice and firm around the turns (a corner carver I can take to through the mountains or on a track/autocross once in a great while) but still nice enough to comfortably cruise and not feel every bump in the road. Kind of like the Green Brick and Tim Werner's Valiant.

I know Hotchkis, Hellwig, and Firm Feel are all great suspension companies. Hotchkis is very local to me (and currently has a 20% promo code) and Firm Feel has pretty good prices as well. I obviously can't afford to replace everything at once, so this will be a piece by piece build up.

So where should I start? I was planning on getting some good shocks and probably a tubular sway bar first. For shocks I was thinking either Hotchkis's new Fox shocks or Bilsteins from Firm Feel. And for the sway bar I was leaning more towards Hotchkis or Hellwig (need more info on the tubular Hellwigs though). Would it be ok if I mix and match suspension components from both (or more) companies? All input, formulas, and information is greatly appreciated as well as any articles you can find on the web. Thank you!
 
Doing the bushings to improve handling is a good start. There's some discussion around whether to use rubber or a polyurethane bushing of some sort. For a canyon carver, I use PST's polygraphite. It's a little harsher and a little sharper than rubber. I don't have the squeaking issue that some have reported with other brands.

Holding off on wheels and tires until you to a BBP conversion is a good idea. Try to do both ends of the car at the same time as it is a pain to lug around two spares.

There are going to be many opinions that differ from mine on the topic of springing. For springs, it's hard to go wrong with a .920 inch or larger bar up front. For the rear a 5 or 6 leaf spring. New rear springs will improve control and raise that saggy rear end. Don't forget shocks. I have Monroe Gasmatics on the Demon and Delco Pleasuride on the Custom. Both are high pressure gas units that give a pleasant, controlled ride.

If you're going to be doing some serious canyon carving, I recommend either a Panhard bar (aka track bar). The bar limits the lateral shift of the rear axle when the car is turning. Although new springs will help, under hard cornering, the axle tends to want to pull them over allowing the tire to contact the spring and/or the bodywork of the car.

I personally am not a fan of the Panhard bar because it limits suspension travel more when turning one way than the other. I recommend the Panhard bar over the Watt's link because the bar can be purchased off-the-shelf and is fairly easy to install.

Finally, after you get the bushings replaced, you will need to get the car aligned. This chart from Allpar lays it out. Your car may not give you the ability to hit these numbers. If all else is well, take what you can get and run with it. My Custom would only let me adjust to +2º caster, so I went with it and the rest of the Max. perf. street settings. I'm a happy camper with it.
 

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If the suspension is "stock" an hasn't been rebuilt recently then you need:
LCA bushings, UCA bushings, strut rod bushings, upper ball joints, lower ball joints, inner tie rod ends, outer tie rod ends, pitman arm, idler arm, rear leaf spring pivot bushings, rear leaf spring shackle bushings and a set of decent shocks. This will get you to a good starting point for upgrades and is the first step regardless. Doing anything else without doing this first is a waste of time and money. This will really make the car drive better.

From here, consider a front sway bar, HD rear leaf springs and larger torsion bar in that order.
 
All good points made above. Most of your parts are 44 years old and worn out I would bet.

I replaced the front end with a rebuild kit from PST. I used the .920 torsion bars from Mopar Performance, and a six leaf set up from ESPO. Welded in some MP sub-frame connectors. Monroe gas-matic for shocks. You would be surprised what a difference this made. I will be adding a sway bar to the front soon.

It won't turn your Dart into a canyon carver, but it will give a good foundation to build off of.
 
I agree with C130 Chief. I would add, in terms of shocks, to also take a look at RideTech. they have a shock line (also partnered with Fox) that includes an electronically adjustable shock to go from a plush ride type dampening to a more performance oriented dampening. They also have single, double, even triple ($$$) adjustable shocks. There shocks have been getting rave reviews on some other forums (pro-touring.com, lateral-g.net, and others). They continuously perform, and place, well in auto-cross competitions and track days. I don't believe the new Hotchkis/Fox shocks are adjustable, but I could be wrong. They have already determined the optimal valving for each application and sell that. I don't really care too much for something that can be adjusted at all to your specific vehicle, because they all differ. That said, I'm using the electronically adjustable RideTech's in my build.

As BrianT said, definitely get ALL the bushings, etc, replaced, then move to springs/shocks/sway bars.
 
I would start with a rebuild. All bushings, ball joints tie rods... Etc.

At the same time as the rebuild I would got to a 1" torsion bar.

Then I would go and do the rear springs and associated bushings.

Don't forget the proper alignment.

Then frame connectors.

Then the sway bars.

I would also do a firm feel stage three box along the way depending on the money situation.
 
Joe hit the nail on the head. Start with a good rebuild and then improve from there.
You wont have any road feel with the stock power steering box.
 
Thanks for all the input guys! It seems most people are saying to rebuild the suspension and increase the spring rate. Can someone help me pick a rebuild kit from PST? There's quite a few on here and I hardly know what I'm looking at and what's the difference. I'm currently running Kelsey-Hayes up front. And along the lines of Torsion Bars I was thinking of going with at least a 1" bar (not initially, but we'll see). And a FF Stage 3 Box is definitely on the list of priorities (maybe early Springish). The panhard bar and watts link are new to me (I vaguely remember hearing about them once) but I'll do my research on them. I doubt I'd ever do that because as of now I'm running a 7 1/4 rear end. Would like to go with the 8 1/4 or even the 8 3/4 when I collect parts for bbp.
 
MuuMuu101 said:
Thanks for all the input guys! It seems most people are saying to rebuild the suspension and increase the spring rate. Can someone help me pick a rebuild kit from PST? There's quite a few on here and I hardly know what I'm looking at and what's the difference. I'm currently running Kelsey-Hayes up front. And along the lines of Torsion Bars I was thinking of going with at least a 1" bar (not initially, but we'll see). And a FF Stage 3 Box is definitely on the list of priorities (maybe early Springish). The panhard bar and watts link are new to me (I vaguely remember hearing about them once) but I'll do my research on them. I doubt I'd ever do that because as of now I'm running a 7 1/4 rear end. Would like to go with the 8 1/4 or even the 8 3/4 when I collect parts for bbp.
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IMHO, you are way far on your Dart project from buying front suspension. You have all kinds of safety and realiablity issues to resolve first before buying any upgrades.

But after you get that all done...

An economical first major step would be:

Tire upgrade: 225/60/15 or 225/60/14 minimun. 16", 17" rim with better rubber would be great too.

front and rear sway bars. Hellwig if you are on a budget.
1" to 1.03" Torsion bars. The ones that go on sale.
Moog front suspension parts as necessary
Moog offset K7103 upper control arm bushings
Bilstein RCD shocks. KYB's on a tighter budget.

I'd try running that power steering pump pressure reducing deal the Ehrenberg wrote about in Mopar Action magazine before buying a rebuilt steering box just to get the firm feel.

All that will make it feel completely different/better for not a whole lot of money.

You have front KH disks right now. When you get them working properly, they work well with a starting suspension upgrade.
 
autoxcuda said:
IMHO, you are way far on your Dart project from buying front suspension. You have all kinds of safety and realiablity issues to resolve first before buying any upgrades.

But after you get that all done...

An economical first major step would be:

Tire upgrade: 225/60/15 or 225/60/14 minimun. 16", 17" rim with better rubber would be great too.

front and rear sway bars. Hellwig if you are on a budget.
1" to 1.03" Torsion bars. The ones that go on sale.
Moog front suspension parts as necessary
Moog offset K7103 upper control arm bushings
Bilstein RCD shocks. KYB's on a tighter budget.

I'd try running that power steering pump pressure reducing deal the Ehrenberg wrote about in Mopar Action magazine before buying a rebuilt steering box just to get the firm feel.

All that will make it feel completely different/better for not a whole lot of money.

You have front KH disks right now. When you get them working properly, they work well with a starting suspension upgrade.
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Thanks! I've been waiting for you to chime in. :D I will not be installing any suspension components or anything till the car is running and driving safely. As far as I can tell, and I may have forgotten something on my list, the two major things that need to be repaired are the steering coupler and shaft (which I have on me) and fixing the firewall along with installing the new MC (where I think I've come to my decision on what I want to do). These will be tackled within the next month or so (along with replacing hoses and flushing the radiator). We'll see how it runs after that if anything mechanical needs to be fixed or swapped out.

With regards to wheels, I don't really want to swap out new wheels and tires, especially since I'm still on the sbp. But maybe I'll look around for some tires I can mount on there. However, I don't know how wide my wheels are (I'm thinking 4.5-5.5") and a 225 might be too wide for them.

I'm not necessarily on a strict/tight budget. I would just like to upgrade that part once and not have to worry about it or feel like I should upgrade it again for a long while.

O, and does Hellwig even have tubular sway bars for A bodies and if they do, do you know how much they cost and where to get them?

But thanks (everyone) for giving me a starting point to think about! :blob:
 
I agree with all that suggested rebuilding what you have now, all bushings, ball joints, tie rod ends, idler and pitman arm as needed, and get the front end tight first, then upgrade torsion bars, rear springs, and shocks at the same time. These two steps will vastly improve handling, and steering response.

Final tightening up will come with installing subframe connectors, and front anti sway bar (anything but Addco). Rear anti sway bars on A Bodies if not sized correctly can make these cars prone to easy over steer, so hold off until you can assess all your work for a few thousand miles before getting one.

After all those items have been installed, have steering gear rebuilt to stage II or III if yours is worn out.

The above is the level my 67 Dart ragtop is at with a stage II gear and 0.940” torsion bars. It corners flat, responds very well to steering impute, is not over boosted twitchy, and hands & rides like a modern car. Also I rebuilt the Dart’s manual KH disk brakes, and rear 10” drum on an 8 3/4th rear, that cars stops real good with good pedal feel. I used a later model master cylinder # MC36338 (71 & up disk/drum, 15/16” bore), it has a larger fluid capacity than a year correct stock unit.

This repair/upgrade as a big outlay, but the increased level of safety and handling is well worth the time and money spent. Your car will be a pleasure to drive once suspension and brakes are up to snuff.

The fourteen inch wheels will be fine for now, remember these 67-69 cars don’t have a lot of room in their wheel.

Rock Auto is your friend for KH calipers, bushings, and hard parts such as ball joints. Don’t go cheap with hard parts, or you will soon replacing them.
 
MuuMuu101 said:
....
With regards to wheels, I don't really want to swap out new wheels and tires, especially since I'm still on the sbp. But maybe I'll look around for some tires I can mount on there. However, I don't know how wide my wheels are (I'm thinking 4.5-5.5") and a 225 might be too wide for them.

I'm not necessarily on a strict/tight budget. I would just like to upgrade that part once and not have to worry about it or feel like I should upgrade it again for a long while.
Click to expand...


You probably have 5" rims. But with disks you may have (or supposed to have) 5.5" rims. 215/60/14. A 225/60/14 can work on a 5.5" rim.

If you are going to stick with the tires you have on there right now (205/75/14?), just put on the sway bars. And they are the same one you will use for future upgrades. Not much performance added with RCD shocks and T-bars with the limited performance and grip tires you currently have.


O, and does Hellwig even have tubular sway bars for A bodies and if they do, do you know how much they cost and where to get them?
Click to expand...

Yes they are tubular. And their rear sway bar is adjustable.

Price and look at them here:

www.summitracing.com

www.jegs.com
 
Now will there be a noticeable change in handling (granted with better wheels and tires) between the Hellwig 1-1/8 bar, Firm Feel's 1-1/4 bar, and Hotchkis's 1-1/2 bar?
 
MuuMuu101 said:
Now will there be a noticeable change in handling (granted with better wheels and tires) between the Hellwig 1-1/8 bar, Firm Feel's 1-1/4 bar, and Hotchkis's 1-1/2 bar?
Click to expand...

Not that noticable with the level of your other upgrades. Use the rear adjustable sway bar to tune your balance.

The Hotchkis and Hellwig are hollow. That will save a few pounds.
 
All the way back to post #2 for a bit.....

2 Darts said:
Doing the bushings to improve handling is a good start. There's some discussion around whether to use rubber or a polyurethane bushing of some sort. For a canyon carver, I use PST's polygraphite. It's a little harsher and a little sharper than rubber. I don't have the squeaking issue that some have reported with other brands.


If you're going to be doing some serious canyon carving, I recommend either a Panhard bar (aka track bar). The bar limits the lateral shift of the rear axle when the car is turning. Although new springs will help, under hard cornering, the axle tends to want to pull them over allowing the tire to contact the spring and/or the bodywork of the car.

I personally am not a fan of the Panhard bar because it limits suspension travel more when turning one way than the other. I recommend the Panhard bar over the Watt's link because the bar can be purchased off-the-shelf and is fairly easy to install.
Click to expand...

2 Darts, those last two paragraphs confuse me. The recommendation of the Panhard bar jibed with what I thought I knew. Do I understand the last paragraph to mean that you prefer the Watts linkage for yourself, but recommend the Panhard to the original poster for the reasons you stated.

Sorry if I sound like a blockhead, but the wording was just a little tangled for my tiny little mind.

ATB

BC
 
64ragtop said:
All the way back to post #2 for a bit.....



2 Darts, those last two paragraphs confuse me. The recommendation of the Panhard bar jibed with what I thought I knew. Do I understand the last paragraph to mean that you prefer the Watts linkage for yourself, but recommend the Panhard to the original poster for the reasons you stated.

Sorry if I sound like a blockhead, but the wording was just a little tangled for my tiny little mind.

ATB

BC
Click to expand...

Yes. I prefer the Watt's link. First saw the link used under Dan Gurney's AAR. I applied it to a circle track racer I crewed on. Driver raved about handling, car owner liked not chewing up the inside of the RR tire on the spring. I've been hooked ever since.

I see some reason for confusion. I said ...I recommend either a Panhard bar (aka track bar) but I never provided an or to go with my either. Please forgive me. I thought I'd omit the Watt's link from the sentence, but neglected to get rid of the either. (Skipping English in HS has caught up with me.)

Don't think you sound like a blockhead. I'm still working on my English. FABO has been great practice. lol.
 
clifftt said:
Autox: Did you use one K7103 bushing and one regular bushing on each side, or two K7103 bushings on each side?
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Two on each side (one kit). I wouldn't skimp with just one offset per side. Because if you were just short of what you wanted, you'd have to take everything apart and redo the press-work. Not worth the cost of another kit vs std bushings.

I was able to get 5 deg positive caster, 1 degree of negative camber. So, lots of adjustment. If I went with less camber, could have got even more caster!

**Just made a diagram with bushing installed to help explain
 

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Best front suspension thread I've seen yet. Thanks for the education.
 
autoxcuda said:
I was able to get 5 deg positive caster, 1 degree of negative camber. So, lots of adjustment. If I went with less camber, could have got even more caster!
Click to expand...

That is a lot of red for an alignment. You must have had your alignment tech steaming out of his ears with thoughts of this car is broken and I hate old cars. Seriously, though does it drive straight? With your cross camber and caster both pulling right I know it would have some drift with the road crown we have around here. The numbers on my valiant are very close to yours, but I got mine using rms uca's. Five degrees caster and manual steering makes you man up a little at parking lot speeds.
 
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