Front end rebuild 1972 Duster

Kern Dog · Aug 14, 2024

This car was bought in 2007 as a slant six, 3 speed on the column 4 wheel drum brake “Gold Duster”.
My brother in law wanted to get into the Mopar hobby so we bought this car to fix up.
In 2007-2008 we (mostly me!) did a 360 swap along with a 4 speed and 8 3/4” axle and front disc brakes. I painted it in 2011.

Jeff couldn’t get the hang of driving a manual transmission (millennial) so I swapped in a 904. Eventually he gave up on the car and I bought him out.
Now I’m tasked with addressing some of the short cuts we (I) did back then to get the car moving. For now, I’m working on the mechanical stuff, starting with the front end.
When up in the air, it is toed IN.
On the floor, it is toed out.

The UCA bushings are cracked and long overdue for replacement.

I have some good polyurethane bushings to use…

But to maximize caster, I’m going with the Moog K-7103 offset bushings.

I’ve found that these can make a 2 degree difference in positive caster. I was able to get almost 6 degrees of caster in my Charger with stock UCAs and these offset bushings. I know it sounds impossible but I verified it with different equipment and it came up the same.
Since I’m on the subject of caster, here is something that I found. Some of you may already know but I’ve just now noticed…
The strut rods for A body cars changed sometime in the 70s. The working length changed at the same time that the front section changed from coarse thread to fine thread.

A response in the Q&A section of a Mopar Action magazine covered this. At some point, the strut rods changed from 16 9/16 to 16 3/4”. The rear stayed fine thread.

Kern Dog · Aug 14, 2024

The two strut rods.
Coarse thread:

Fine thread:

It looks like the coarse thread is the first version. They are the shorter ones. This car has one short/coarse thread and one longer/fine thread. This will affect caster if the same thickness bushings are used. I thought I read that the bushing changes when the length of the strut rod changed. In theory, the shorter length rods used a thicker bushing so the overall working length was the same. This means if you didn’t pay attention, you could have three combinations. 1) The correct bushing , resulting in proper alignment. 2)Short rod/thin bushing for more caster at the risk of lower bushing distortion. 3) Long rod/big bushing resulting in excessive negative caster.

I have a 16x8 wheel in front with a 225-50-16. The right side strut rod is the longer one. Note the difference in the clearance to the rear of the wheel opening.
Left:

Unscientific but that is about 2 7/16”.
Right side:

That is around 2” even. That is a huge difference. The lower ball joint is pushed back enough to make a 7/16” difference. Caster on this side is probably several degrees negative. I’m going to replace the RH strut rod and bushings. This and the offset bushings should get me at least 3 degrees of caster.

340sFastback · Aug 14, 2024

Around the 8 minute mark in this video he goes over the different strut rod lengths:

Kern Dog · Aug 14, 2024

Setting them side by side does show a difference but a tape measure tells you exactly how much difference there is.
Maybe the reason that my Charger has been able to get such great caster numbers is because I have urethane strut rod bushings that are thinner than the fat rubber ones. I'll use the same principle with this car.

Garrett Ellison · Aug 14, 2024

Just out of curiosity because of some experiences I've heard with the urethane, how has the long term durabilty of urethane strut rod bushings compared to the factory rubber that you replaced them with in your charger? I've figured said issues were probably a side effect of another problem with overall setup and alignment.

Kern Dog · Aug 15, 2024

I put the urethane bushings in the Charger in 2002 when I rebuilt the front end. I actually used urethane everywhere but changed the LCA bushings to rubber a couple years later, then I pulled the urethane UCA bushings to put these offset bushings in around 2011-2012. The strut rod bushings are still in the car and still look great. I had the front end apart in 2022 and the strut rod bushings looked fine. I have about 17,000 miles on them since they were new. I figured that the LCA in urethane sent too much vibration to the car with very little gain in control and handling, same with the UCA bushings.
I went with QA-1 UCAs in the Charger....

I went with the QA-1 arms in the Charger because it is a keeper. I'll never sell the car.
I could have gone with the same UCAs in this Duster but I'm not keeping this car. I'm not against spending money to get this car handling well but the aftermarket arms are more of a luxury than a necessity.

Kendog 170 · Aug 15, 2024

I had a bend in one of mine when assembling. 4 years later I'm noticing the same type fender measurements you have. I'm sure the rod I used already had the nut with it as that is how I store them. I will be checking the front threads soon. I too did the offset bushings.
Thanks

Kern Dog · Aug 15, 2024

Sometimes a man needs an excuse to spend money on tools.

Yeah, Harbor Freight.

Often times I used to get started on a project like this on a Friday and have to wait until Monday to take control arms in to get the bushings pressed in. Who wants to wait?
One time I brought in the UCAs with the offset bushings in boxes. I clearly told the guy how I wanted them installed but when I went to get them, they were in wrong. The machinist told me that he did it the right way. I told him that I knew what I was doing and wanted them installed the way that I told him.
Having a press here means I will be able to do stuff like this when and how I want it done.
The underside was dirty so….

The tie rod lengths were similar from left to right. Back in 2007 I converted the linkage to the 1973-76 style with later idler and pitman arms too.

It isn’t like I am pulling the oil pan that often but the 73-76 linkage is better in my opinion. I used a 73-76 spool mount type V8 K member too.

Kern Dog · Aug 15, 2024

Do you have one of these?

They are great! I don’t remember where I got this one. It is aluminum so it is less likely to nick a torsion bar.

There is a condition that some call mission creep. I call it The Snowball Effect. While under the car, I saw this:

I’ll replace all of these, even the ones that look okay.

1WildRT · Aug 15, 2024

How about the ones in the back????

Kern Dog · Aug 15, 2024

1WildRT said:
How about the ones in the back????

You mean the ones blocked by the transmission?

At some point years ago I automatically punched in new core plugs when I did an engine swap. I’m hoping that with this one, I at least replaced the ones on the back.

Kern Dog · Aug 15, 2024

I didn’t remember the condition of these parts in the front end since it was so long ago that I worked on this part of the car. It looks now like just about everything is worn out. All four ball joint grease boots were torn so I didn’t feel bad using this:

The drivers side lower ball joint could be pulled in and out almost 1/4”.

The LCAs and UCAs were junkyard parts that I pulled in the early 2000s when you could still occasionally find a disc brake Dart at Pick N Pull.

I did replace the bushings in the LCAs but look what 17 years did to them.

There is less than 10 miles on these bushings. Time and weather did this.
I waited to order a front end rebuild kit because I didn’t know what I would need. I thought I might be able to get away with UCA bushings and grease boots.

Kern Dog · Aug 16, 2024

I made a call to PST to make an order.
It seems that since Covid sent so many people to a "work from home" business model, that situation still exists for some companies.
I got a guy that had the TV on in the background drowning out a portion of what he said. I asked him if he had an angry person in his office and he said, no, that is just the TV.
That isn't professional, man.
I had to ask what was included in the kit, he rambled off the parts as if he were annoyed that I asked.
I mentioned the FABO/FBBO 10% discount, it came up at about a 3% difference. I caught it, he didn't.
The whole conversation, he seemed distracted. The TV should not be on if you're working.
I got the rebuild kit with rubber components, not the urethane. I did order urethane strut rod bushings though. I have them in the Charger and they work well.
I had to ask the guy how long to expect delivery. Maybe a week?
I know that PST is a sponsor but this guy on the phone wasn't professional at all. I've bought from this company before and have been happy with their products but a sales rep like this guy reflects poorly on their image.

Kern Dog · Aug 16, 2024

Today I was heading back home and remembered that I took almost everything off the front end yesterday.

The sway bar is still in place. That there is a modified 1 1/4” solid bar originally from a 1973-87 Chevy/GMC 2 wheel drive 1 ton C-30 truck.
In 2000 when I bought my Charger, I was looking at ways to improve handling with junkyard parts. I found that the front sway bar in those trucks had a similar shape once you cut the ends down a bit. Nobody makes an 1 1/4” front bar for an A body but a few vendors make them for B body cars. For under $50, I modified one of these for my Charger. I’ve made 5 of these. I’ll go into detail on what is required to do it closer to the end of this thread.
I forgot about how hard it can be to crank the upper ball joints out with the arms out of the car.

Chevy guys have theirs pressed in. Ignorant repair shop guys have been known to try to press them in the Mopars! They screw in and out, which confuses the other guys. The top of the ball joint uses a strange pattern.

Many of the sockets that were used to service these ball joints use a 3/4”drive.

I’ve tried cranking these out with them in a vice with mixed results.

The more stubborn they are, the higher risk of deforming them when in a vice.

I don’t know if I read or heard but the best way seems to be to loosely set them back in the car.

Now the car anchors the UCA in place so you can screw them out.

I used a 30” cheater bar but was careful to not let it slip. One wrong move and you can have bodywork and paint in the future.

The parts aren’t due until next week. Until then I have some cleaning and refinishing to do.

Kern Dog · Aug 16, 2024

I should clarify some things that the newbie’s may not know. Some of this stuff I’ve known for years, other stuff I’ve just picked up over the years. If you see a mistake of mine, feel free to set me straight. I’m willing to admit fault and learn from it.
There were some changes to the suspension and steering components over the long run of the A body line. In 1973, all the A-B-E and maybe even the C body cars had some changes. Some of the changes were aimed at noise reduction and a smoother ride. The A body got revised steering linkage. The disc brake equipped cars now had the bigger and more common 5 on 4 1/2” hub pattern which matched the B-E-C body cars. I learned awhile back that while front drum brake cars were fading away, they still made them through late 1975 for the 1976 model year but….now this is just what I have read….as of January 1 1976, front disc brakes were made standard. The front drums were 10" diameter and they used a large upper ball joint though the wheel hub was the old style 4" circle.
All disc brake 1973-76 cars used the same upper ball joints as the 62-72 B and all E bodies. They also used the same lower ball joints as those cars. This is a situation where they wisely repurposed existing parts to fit other cars.
The disc and drum brake 1972 and older cars had the smaller upper ball joints and lower ball joints with a different angle to the steering arms in them. This is why when you do a drum to disc swap with 73-76 parts, the toe setting of the steering gets weird, needing adjustment.
Feel free to correct me if I missed something.

v8dve · Aug 17, 2024

Hi KD, got to do my front end soon and very good info here to help me :thumbsup:

What is that 3/4 Drive socket called / sold by, that you used to unscrew the ball joint unit?

Thanks

townsend · Aug 17, 2024

v8dve --- Mancini Racing # MRE23457

Kern Dog · Aug 18, 2024

Thank you, Townsend.
I got the socket in a stash of parts I got from a guy years ago.
Today I sandblasted the UCAs after getting the ball joints out. I painted them a semi-gloss black Rustoleum.
The LCAs....I've never pressed bushings out with a press before. I remember reading about how to get the shaft, the bushing then the shell out but today was my first time doing it.
I'll do the right side tomorrow and post pictures but back to the recap:

I found it to be a bit clumsy....balancing the LCA and spacers to press out the shaft first.
The bushing gets pried out with a screwdriver. That is easy.
If you're using poly bushings, you leave the shell of the old bushing in place but I'm installing rubber bushings again. Back in 2001, I fell for the hype of Polyurethane. Better handling, modern feel...This is true with GM cars where the rubber in the bushings is huge. Ours are pretty thin so when the rubber is in good condition, the added stiffness of a poly bushing is minimal but the vibration increases a lot.

Kern Dog · Aug 18, 2024

For the factory, the upper control arms were the sole way to adjust front end alignment. In the years since these cars were built, some enterprising minds have come up with a few more ways to fine tune the settings. When stock, these cars were fitted with skinny bias ply tires that didn’t grip that well or last as long as today’s tires. The alignment settings back then often had little if any caster and zero or positive camber. With today’s tires, you can do a lot better. One way to get more caster is with adjustable strut rods. These pull the outer end of the lower control arm forward like so:

That is an extreme angle just for the purposes of demonstration. Several vendors offer adjustable strut rods including PST, a sponsor of this site.
I like the idea to a point. I wonder though if they might put the lower control arm bushing in a bind if these are cranked in too far.

Kern Dog · Aug 18, 2024

When these cars were still being used as daily drivers, the front ends sometimes needed to be rebuilt to keep from chewing up the tires. Corrosion, collisions and frame/chassis twisting with wear often made stock alignment settings hard to achieve. Moog stepped in with what they called “Problem Solver” bushings:

These are the K-7103 bushings that you may have heard of.
My understanding is that some cars developed negative camber issues over time and the bias ply tires didn’t fare well with that. These offset bushings look like so compared to standard bushings.

Imagine the black line is the upper control arm mount in the car.

The original intent of the Moog offset bushings was to compensate for chassis wear by allowing mechanics to move the control arm out further.

This restored the camber to be within specs for bias ply tires. HERE is where it gets better.
When you install the bushings in the control arms different from their instructions, you can improve the caster and camber settings way beyond the factory limits.
Modern radial tires can take some negative camber without excessive wear. There are limits but I run 1 degree negative camber in my Charger and the tires wear evenly.
If the bushings are installed on this LEFT control arm where the offsets are like so:

This will push the front mount OUT toward the fender and the rear mount IN toward the engine…from this:

To this:

This tilts the top of the steering knuckle/spindle to the rear, increasing caster.

Kern Dog · Aug 18, 2024

This I’m first time pressing in bushings with an actual press.
I have done the caveman method of a hammer, sometimes a vice but this method is safer and less likely to bend the control arm.

It is a juggling act though. You need stuff to press on and stuff to allow the bushings to pass though.

Boom.

Next is to squeeze in the spacer/washers.

Then I can put the arm back in the car to install the upper ball joint. I’ve seen guys use impact wrenches to crank them in but no thanks. That seems like it could strip the threads in the control arm.

Kern Dog · Aug 18, 2024

I took measurements of the overall width of the chassis and the UCA mounts.

9 3/8”.

Same there.
The measurements with the new bushings was 9 1/2 so I had to tap it in with a rubber mallet.

I wire wheeled the alignment cams and hardware, then smeared them with RPM paste. This stuff keeps bare metal looking fresh with no flash rust forming later.

With the alignment cams in place, do NOT tighten the hardware, just run it up until the nuts seat. If you tighten everything right now, the bushings are locked in place with the suspension in extension. You want to tighten the nuts during alignment with the car at it’s final ride height. The reason for this is because with the bolts tight at ride height, the bushings are in their neutral state. The suspension will move up and down twisting the bushings as intended. If you tighten the hardware with the suspension hanging, once you set the car back on it’s tires, the bushing is now in a twist and will wear out much faster.
With the UCA in place, I screwed in the upper ball joint.

Backing up a moment. Here is what it looks like just before stuffing it into place.

mopowers · Aug 18, 2024

Good stuff! I've never used those offset UCA bushings before. Do the spacer/washers sit square with the bushings? I suppose that's no problem once everything is bolted up?

Kern Dog · Aug 18, 2024

Once they are pressed in, they do sit correctly.

The only issue for me is that the overall width was 1/8" larger than before so I had to encourage the arm into place.

The task of pressing out the lower control arm bushing takes a few steps. First, the shaft itself is pressed out.

Again, this takes the use of some juggling and spacers. I have some 1/2” drive sockets and sections of exhaust pipe.

The shaft is out but…

See the bushing here with that inner sleeve?

That stays on the shaft when you press the shaft out.

The sleeve has to come off. More on that in a moment. First, I pried out the rubber bushing.

Kern Dog · Aug 18, 2024

The sleeve on the shaft can be stubborn to remove. There are many methods to do it, again… this is my first time doing it so I just put in a vise….

I took a 4” grinder with a flapper disc to grind away and thin out a section. This made it easier to chisel a groove.

Then just twist it off.

I ran the shaft across the wire wheel to tune it up, then I set it aside.

It looks like the last time these bushings were replaced at a machine shop, (2007) the man took a cutoff wheel to slice off the old bearings shell and went deeper than necessary. This was another method that I didn’t do specifically because of this. Grooves like this don’t add strength to the shaft.

If you’re more careful than that guy, it is another way to go.
The next step is to remove the outer shell of the bushing from the control arm. Many of you already know about this but for the rest of you, I’ll explain what is involved.

The outer bushing shell has a lip at the top that acts as a “stop” to properly position the bushing.

The problem is, that shell only comes out one way and there is nothing to press on from the back side.

Front end rebuild 1972 Duster

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