Tighten up that rear end :)

[Wietse]

Hey all,

Since i have rebuild the front and rear suspension of my '69 Coronet R/T i still do feel the need of adding something to tighten the rear axle.
When i was for an wheel alignment the good man also pointed out to me the rear axle is only kept in place by the springs and recommended me to look into improving something here will do a lot of good in car handling.
A 4-link system would be asking for a perfect world, but as this car is not going to be a racer i am far from willing to spend $2-3-4K on suspensions systems like that.
So now i was wondering about other options to give that rear axle a bit more strong points.

Would a rear sway bar also provide some of this or is this only attacking body roll?
Any more simple ways of creating your own 4-link bars or something?
Currently i've got brand new XHD leaf springs, Polygraphite bushings and Bilstein shocks.
Front has same brand shocks, original torsion bars and a 1-1/8" solid sway bar.
I did read not to go too tight on the rear end as this results in a unpredictable driving car with a rear end that can kick very fast.
Anyone so good tips?

Thx for reading

 

[5.7 hemi]

RMS has a 4 link with coil overs for about 1500. You could get a rear sway bar for about 150-300 depending on who makes it and where you buy it.

 

[66Satellite47]

Sounds like you have great suspension setup. A rear sway bar would provide some added roll control. A 4 bar system sure doesn't seem like an improvement, leaf springs work fine. A person can play around with leaf spring configuration. IMHO the XHD setup is a darn good starting point.

 

[493 Mike]

Have you considered a panhard bar? that will keep the axle centered under the car while cornering. Jegs and Summit have kits if you can fabricate mounts?
Mike

 

[Wietse]

Thx for the input guys!

It's not like the car is swinging all over the place, but you do notice some movement back there.
The alignment shop I was also showed me the few millimetres difference between left and right wheel centre's. (front to rear)
He mentioned, if you would drive it off the lift and put it back on it will be different again so it was not something to worry.

@493 Mike: I never heard of a panhard bar, so I will go do some investigation about this. I can fabricate mounts myself so a little DYI is no problem.
I just did not see the point of buying these expensive kit, which to me is the way to go if you are racing.

 

[moparedtn]

A rear sway bar has been on my to do list for the GTX, just not a priority.
Now that she's a running & driving rascal, things like the rear sway and some braking improvements are next.
I looked on Summit real quick and they have an "in-house" kit that's far and away the most reasonable.
Wonder who makes it for them? Is 7/8" bar diameter sufficient for our cars?

 

[WileERobby]

Once said that to the wife. Took me awhile to recuperate from the immediate head injury.

 

[451Mopar]

The leaf springs do a pretty good job. If it feels really loose, pull the axles and check the axle bearings. It could be an indication the bearings are going out? If the bearings are good, make sure end-play is adjusted correctly (if it still has the OE style axle bearings.)

 

[Wietse]

As from reading up on the rear sway bars here across the forum, it is not advisable to go too heavy on the rear sway bar.
The rear end should stay soft(er) then the front, otherwise the car becomes really fast over steered and nervous.

 

[AR67GTX]

As from reading up on the rear sway bars here across the forum, it is not advisable to go too heavy on the rear sway bar.
The rear end should stay soft(er) then the front, otherwise the car becomes really fast over steered and nervous.

That's correct and a rear swaybar can promote less understeer and even get into oversteer unless the front is upgraded too. But it sounds like you have an upgraded front sway bar so typically that should allow you to add a rear sway bar and maintain balanced handling. I just wouldn't go too large. A panhard rod would be a nice addition but unless you are really doing some really serious driving in that thing I don't know how noticeable it would be.

 

[aeon280]

I just purchased the summit front and rear bars and they are nice. The front took about an hour to bolt up and the rear is going to take a little longer due to having to move some lines for clearance on the axle. The rear bar is also adjustable so you can stiffen it up more if needed.

 

[Dennis H]

69 Coronet R/T here. Bilsteins. I did put a spacer on the left rear only to prevent the 295/50/15 Cooper from kissing the inner leaf when pushed hard due to sidewall flex. Also, inserted one modified truck leaf each side to give slight rake. Hotchkis Bar on the FRONT only.
Handles well, compliant ride yet comfortable. Best part is the predictability. Tells you when you have reached the edge.

 

[rlem1977]

... i still do feel the need of adding something to tighten the rear axle.

When you say tighten, what exactly are you trying to correct? What does the do, or not do, that you want to fix? It could be that different tires would be a good way to improve the car.

 

[493 Mike]

My panhard bar. And the drag race antisway bar I'm going to use on the street.
Mike

 

[Wietse]

The suspension part is fine, caused by the Bilstein's and the new leaf springs and bushings.
It just has a little "swing" going hard left to right or vice versa, which as highlighted by the alignment shop is caused by the fact that nothing else but the leaves keep the rear axle in place.
So the side way movement (swing left to right an v.v.) is what i notice i guess, regardless it would be a good upgrade for a more balanced car.

So like a rear sway bar makes a connection between chassis and rear axle, to me adding some rigidity to the rear axle...right?

 

[Wietse]

I just purchased the summit front and rear bars and they are nice. The front took about an hour to bolt up and the rear is going to take a little longer due to having to move some lines for clearance on the axle. The rear bar is also adjustable so you can stiffen it up more if needed.

Did you buy this rear one? https://www.summitracing.com/int/parts/sum-720231/overview/year/1969/make/dodge/model/coronet

How does that install, i think i've seen different ways but which side connects to the axle?
Both ends on the axle or the ends on the chassis?

 

[aeon280]

The suspension part is fine, caused by the Bilstein's and the new leaf springs and bushings.
It just has a little "swing" going hard left to right or vice versa, which as highlighted by the alignment shop is caused by the fact that nothing else but the leaves keep the rear axle in place.
So the side way movement (swing left to right an v.v.) is what i notice i guess, regardless it would be a good upgrade for a more balanced car.

So like a rear sway bar makes a connection between chassis and rear axle, to me adding some rigidity to the rear axle...right?

You might also consider poly of solid spring and shackle bushings as well. sounds like maybe your rubber ones might be worn out.

 

[aeon280]

Did you buy this rear one? https://www.summitracing.com/int/parts/sum-720231/overview/year/1969/make/dodge/model/coronet

How does that install, i think i've seen different ways but which side connects to the axle?
Both ends on the axle or the ends on the chassis?

The length of the bar connects via ubolts and bracket to the axle. There are 2 end-links that connect to the frame rails ahead of the axle. in the link you provided is the instruction sheet via pdf that is fairly detailed.

 

[Wietse]

Haha, never noticed that summit provides any instructions sheet with it

You might also consider poly of solid spring and shackle bushings as well. sounds like maybe your rubber ones might be worn out.

I just replaced everything, including new poly bushings.

 

[Malicious]

My panhard bar. And the drag race antisway bar I'm going to use on the street.
MikeView attachment 626588

Does the lanyard bar make much of a difference? Was that a kit? I like the bolt on nature of it!

You could also install sliders instead of shackles.