Suspension Upgrade

CMXBROWNIE

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Hi guys, this may have been discussed before, but I am thinking of upgrading the CMX's front end. Looking at the Firm Feel sight and also PST. My question is: Have any of you attempted to rebuild your front end yourself? I have never worked on a torsion suspension, and am concerned about messing up the torsion bars. Also, if you have done the poly urethane bushing upgrade, was it worth it? Thanks
 

Bruceynz

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Hi,

I have done a fair bit of work to my Cordoba, Firm Feel top A arms with more caster (I think mine is at 5 degrees and can go more) I don't have a firm feel power steering gear but I had 2 gears and had one rebuilt with extra reaction springs and bearings fitted and the best fit balls installed. I also fitted the FF alloy body isloators, energy suspension spring pads, KYB gas shocks all round and addco front and rear anti sway bars! Totally different car, gone is the wobbles in the rear end and doesn't wander all over the road like a drunk driver any more! Its actually quite amazing how well they drive when all the jelly rubber is removed!

Thanks
Bruce
 

BudW

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I have rebuilt more Mopar suspension systems than most people has even looked at (and FMJ suspensions, as well).

The torsion bars have the middle support/bushing and end bushing (where it attaches to the control arm). These bushings are not easy to find, are expensive and are not easy to replace. If these bushings are not broken – then I would recommend leaving them alone. If they are broken, then I might recommend finding a pair of used torsion bars, replace the bushings on them, then swap out the torsion bars – just in case you damage your originals (or toss the bar out into the lake (like a golf club), or whatever).

The upper ball joints require a special socket to remove and are usually easiest to remove/install with control arm still attached to car (it is a two handed job and not something to do on/in a vice – for your work bench might start spinning in place).

The control arm bushings are fairly simple to change if you have access to a press. There are a lot of YouTube videos on this if you want to look it up.

The tie rods and idler arm are fairly easy to change.

The pittman arm requires a big socket and long wrench to loosen/tighten. It also requires a puller – which can be rented out by most part stores.


A first timer with a decent selection of tools, rented puller and ball joint/tie rod end separator, ball joint socket and a press – can get job done in a about a full day or less.
If you decide to replace the torsion arm bushings – then add another couple of days to that job.

If you invest in a good set of shocks (not the cheap ones), and greasable ball joints/tie rod ends, then you can do a long lasting and quality repair, yourself.
Not all ball joints and tie rod ends are greasable (so look before purchasing).

I HIGHLY recommend installing rubber upper and lower control arm bushings.
That said, I HIGHLY recommend poly sway bar bushings and for anything else in the suspension.

The reason for rubber control arm bushings is those bushings absorb all jars and bumps instead of transmitting them to your kidneys. I have had cars with poly upper and lower control arm bushings – back when I was in my 20’s and it hurt my kidneys and back – back then. I’m in my 50’s now, so for sure can’t take the ride harshness now.
Even for a full time road race car, poly bushings might be pushing it for ride harshness for a long race. You can feel every rain drop and every ant you drive over – and it goes straight to the kidneys.

I also highly recommend tossing out the rubber K-Frame to frame bushings – for that can immediately make the car feel so much better –just by itself. Replacements using aluminum, poly or even Cast Iron (Mopar Performance parts, long sense discontinued) are available – but are a bit more intensive to replace (with steering gear shaft and exhaust getting in your way – but worth the effort.

I like TTI’s parts but they are a bit on the expensive side.


Note: on my personal cars, I prefer to get replacement arms, bead blast them, get them painted and looking nice first, then swap ‘em out. It makes the job go a lot faster and looking nice when done. A person could purchase rebuilt control arms for that job – but I’m a tightwad and don’t want to spend the extra money on someone else’s labor.
BudW
 

Bruceynz

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Bud you should feel what a cordoba goes like with over 5 degrees caster on them! Come on over, we can wrench on my car drink beer (or coffee) tell Chebby jokes and have fun in my doba on the wrong side of the road for you :D
 

CMXBROWNIE

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Good stuff! I had no clue about the poly A arm bushings. I think I will take it in stages. Shocks and poly sway bar bushings first, followed by pitman arm, idler arm, and rod ends next. Then replace the upper control arms with the ones from firm feel, but with rubber bushings. If I jack the car up with suspension hanging, does that take all the load out of the torsion bars, or do I have to back the bolts off. Thanks for all the help guys!
 

BudW

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My recommendation is to first check and replace what parts are “loose” first.
If multiple parts are loose, then fix the loose steering parts first.

It is easier to overhaul the front suspension all at once – but I understand that is not possible, at times (for a number of reasons).

It is not recommended, or advised, to perform suspension repairs that require ball joint or arm removal – without loosening the torsion bars, first. It is not safe to do so, either.
Now shocks and tie rod ends and so forth, it doesn’t matter.

In addition, all suspension springs (torsion bars, coil springs, leaf springs, etc.) will sag over time – so a minor adjustment is usually required every time that area is worked on.


On a different note, about a year ago, I had a front outer wheel bearing failure on my ’77 wagon. While working on that repair – I discovered the upper ball joint was way loose (at 40k original miles). In this case, I did place car on jack stands, placed a floor jack as close to the wheel as I could get, and jacked car up to a point where car just barely raised up a skooch, then replaced that upper ball joint – without touching the torsion bar.
If doing more than a ball joint, then I do not recommend it.
I did it because I had done a lot of these before and know the risks of doing it.
For someone’s first time – please do it by the book – because we want you stick around. We do not want you to be on the front page of your local newspaper from a “preventable accident”.
BudW
 

CMXBROWNIE

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Bud, so when I back the bolts off the torsion bars, do I count how many turns it takes, or do I have to set bolts to a torque value when setting back up? Excuse my ignorance, but I do not want to end up on the front page of the newspaper. Thank you so much for the advice on this. Things seem fairly tight under the font end. I just want it to handle like Bruceynz describes.
 

BudW

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First of all, the torsion bar bolts – are difficult to turn/twist, with weight of car on them – so before adjusting the bolts, I recommend to first jack car up until tire is almost ready to leave the pavement.

Even then, the bolts are not easy to turn. Soaking the bolts with penetrating oil, a few times (for a few days) might be a good idea.
Also, don't get under the car unless car is supported by jackstands, first!

When performing repairs that require loosing of the torsion bar bolts, you go until the bolt is loose in its socket – which will be at point it is almost no threads remain in the bolt. You will be able to tell when getting close for things will start to get loose in that area.


Ride height procedures:
Before taking measurements, grasp the bumpers at the center (rear bumper first) and jounce the car up and down several times. Jounce the car at the front bumper the same number of times and release the bumper at the same point in the cycle each time.

  1. Ride height is measured from the head of the front suspension front crossmember insulator bolt to ground.
  2. If necessary, turn torsion bar adjusting bolt clockwise to increase height and counterclockwise to decrease height.
  3. After completing adjustment, jounce vehicle and recheck riding height. Both sides must be measured even though only one side may have been adjusted. Front vehicle height should not vary more than 1/4 inch from the specified riding height. Riding height should also be within 1/4 inch side to side.
82 up Ride Height Pic.JPG


82 up Ride Height Spec.JPG

BudW
 

CMXBROWNIE

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Bud, Thank you so much for this valuable Info. I feel more confident about doing this myself. Since my car has white leather interior, the thought of having a greasy mechanic rolling around in there is not appealing. I also have a 4 post lift, so it should be easy to get at (I don't like crawling under cars anymore).
 

BudW

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I just re-read my post – and noticed the picture was not very clear – so I modified the FSM picture - for clarity.
82 up Ride Height Pic a.jpg

Also, that is considering still using factory rubber K-Frame mounts.

- - -
If you are replacing the rubber mounts with something a whole lot better (poly, aluminum or cast iron) – then those measurements will not be correct – sense the bottom half of bushing will not be there.

So, before changing to solid K-Frame mounts (if you have a plan to do so), I recommend re-arching the rear leaf springs first (if you were going to do so) and then set front end height (as normal).
Then measure the front end height to a spot just in front of the K-Frame front lip and record.
Change your K-Frame mounts – to the adjusted measurement. as recorded the sentence above.
The torsion bars will need to be re-adjusted, afterwards

After that is done, re-measure front end height and record for future reference.

Matter of fact, I would suggest checking and adjusting front end height before taking car into shop for a wheel alignment – and just tell them (DO NOT ADUST RIDE HEIGHT)!
BudW
 

CMXBROWNIE

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Bud, Thank you so much for all your help. I am collecting parts and will start into this for my winter project. I think getting the K member bushings up to par first will be my starting point. You mentioned poly mounts. Is there a company that makes those? I saw the aluminum ones from FFI, but the poly seems to me might be the best compromise.
 

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I have a set of FFI aluminum mounts – but they were a bit pricy. I need to get a 2nd set from somewhere (else) for my other car.

My ’77 Wagon has been in a garage most of its life – but even still, I can feel the 40 year old K-Frame to Frame rubber bushings give a lot during an abrupt or sharp turn – for it takes a couple of seconds or moments before the car starts to turn (before tires start protesting), and I know it is those bushings giving a lot - before doing anything.

My ’86 5th Ave steering gear leaks bad and is very loose (I have a TTI rebuilt gear ready to install into car) so I don’t have anything to compare with as far as how it takes abrupt sharp turns.

I will be performing a similar job as yours – but for a different reason.

I have an ’84 Gran Fury police car complete K-frame at home. My plan for it is to take K-frame/suspension apart, weld up and brace the K-Frame really well, get cleaned up and powder coated.

I also have plans on installing LCA (Lower Control Arm) braces:
AR053 FMJ LCA plate.jpg


Rebuild the front suspension, while painting or powder coating those parts, as well.

I’m planning on installing a rear sway bar – which means I need to install a larger front sway bar to compensate. Once done, I’m then dropping my big block engine and transmission onto the K-frame on a special built dolly.

On another special built dolly, I’m going to drop the K-frame with existing 318/999 down (actually, will be raising the car body up), wheel one assembly out from under car, wheel other assembly under the car and drop car body back down over the new engine combo – using aluminum K-Frame mounts in the process.

Repeat process for my other car.

Note: it takes more than that to install a big block into an FMJ body, but was giving an overview on what my plans are. I’m also in the parts gathering process (and have more to gather).
BudW
 

CMXBROWNIE

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So is the big block going in the wagon? You must give details! I love sleepers!! We picked up a complete un-molested parts car (80 Cordoba Ls), mainly for the front bumper. Being a maniac gear head, I have had thoughts of keeping it and doing what you are doing with the wagon, except leaving the peeling and faded paint patina in tact along with stock hub caps. Would love to have fun with one of those new retro look mustake, camaroo, or challenger boys with their nice easy monthly payment super car (sick fantasy I know, but I love Farm Truck!)
 

BudW

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Farm Truck lives a short distance down the road from me (Oklahoma City).
Unrelated, you can hear the street racing going on at night – even during weekday nights.


My charcoal gray 5th Ave is getting a big block 727. Going to leave the paint, as is as well as the "half missing pin stripes" and wire wheel hubcaps on it, as is.

Open the engine compartment, will be a corporate blue big block, with A/C, P/B, P/S, cruise, etc. as well as a black air cleaner (with fresh air duct) and Lean Burn computer (empty shell) hanging off of it. My plan for the car is not a sleeper per se (but it will be), but what it would look like if Chrysler put a big block in an FMJ to begin with (with A/C, P/B, P/S, etc.).
At first glance (and possibly second or third glance), it will appear to be a stock 318.

Never been a fan of black engine paint – so that part will be different.

The engine will be somewhat mild and will use exhaust manifolds. 9.5 compression ratio using ceramic coated pistons, stealth aluminum heads, Stroker crank (to 467 ci), max RPM will be 5,500 (power band will be way down low). I’m looking for a daily driver and something my wife can drive without complaint. I’m just tired of driving a car that (only) does 22’s in the quarter mile.
Going to try to get exhaust as quiet as I can get it (for stealth and also for long distance driving comfort).

I’m actually building two identical engines at same time. One is a used ’73 400 and other is a NOS ’78 400 short block.

The second engine will be either stuck under the shelf (spare) or will be put into my wagon. Again with A/C, P/B and P/S – but this time with car converted to a manual (I don’t care for automatics). Would love to get a 6 speed Magnum installed into it. Either the Magnum or 5-speed Tremec will require transmission tunnel and crossmember modification. My wife can drive a manual – but doesn’t like it.

I’m not fully committed to modifying the wagon at this time, sense that car is still 100% original.

Either car could be taken road racing if wanted (something I would like to do, eventually).
BudW
 
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