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-   -   1969 Firebird, panhard bar with leafsprings? (http://www.hotrodders.com/forum/1969-firebird-panhard-bar-leafsprings-226992.html)

Nuck Chorris 12-09-2012 02:18 PM

1969 Firebird, panhard bar with leafsprings?
 
Would a panhard bar work with a sway bar and leaf springs on a 1969 firebird? How hard with this be to build and weld in myself?

aosborn 01-02-2013 10:39 AM

Yes, a panhard works on leaf spring suspensions. It does a nice job of keeping the rear axle from moving laterally due to deflection of the rubber bushings on the spring eye and shackles. They are not hard to build, but they are challenging to build correctly. My goals for panhard bar installations are...
1. Level at ride height
2. As long as possible
3. Beefy enough so the bar and the mounts don't flex
4. Utilizing end bushings that will last for a long time with highway use (no heim joints)
5. Make it adjustable for fine tuning
6. Usually mount it at the axle centerline to help lower the roll center a bit
7. As close to perpindicular to the longitudinal centerline of the vehicle as possible for strength and control

Regards,

Andy

Jake Brake 01-06-2013 03:51 PM

And if you use a panhard bar on parallel leaf springs it will bind. Absolutely no need for it. Sway bar make it so you can disconnect it too see if it helps or hinders. Most need a beefier front bar

lakeroadster 01-06-2013 04:00 PM

I agree with JakeBrake. Do not use a panhard bar with leaf springs.

A panhard bar pushes the axle left and right, because it is fixed to the frame and rotates around that point. Panhard bars are typically used on coil spring suspensions, and tranverse leaf applications.

A watts link would be better, but still shouldn't be needed on a parallel leaf spring application.

Why are you wanting to install a panhard bar?

kso 01-06-2013 08:09 PM

Yeah, the panhard rod wants to make an arc and the leaf-sprung rear wants to go straight up-and-down. You'd at least have to keep the bar at the same roll center, dead-flat, and disconnect it to do any service. I believe they used them on the old Trans-Am cars, but another mod, if you believe your springs are rolling around any, is to just clamp the spring under the housing with no rubber and let the bushings at the end do all the isolating.

Nuck Chorris 01-07-2013 09:26 PM

mainly because I thought they looked cool and sounded good in the handling book I read. And it's not going to work

aosborn 01-07-2013 11:02 PM

It does work...

gow589 01-08-2013 04:28 PM

I think the issue of a Pan Hard rod arcing the axle left and right is a mute point for a suspension with not a lot of travel (unlike say an off road vehicle). Obviously a watts linkage does not arc but I think the arc for most cars is so small it is not an issue.

I have an old MGB with an engine conversion. It is a pretty spunky car. The problem with MG's is the leaf springs are past their parabolic arch. When you hit a bump they do not do much at first then all of the sudden play catch up. Lousy lousy setup.

I removed a couple leaf springs, added a coil over and threw in a panhard rod. The panhard rod was also added because I went to slightly larger tires and the rubber is about 1/4" from the fenders on both sides.

If there was much arcing at all I would raze a fender but there just isn't. It does exactly as I ask:




http://www.rc-tech.net/cars2/mg2/gal/mg1small.jpg

sedanbob 01-08-2013 05:53 PM

1 Attachment(s)
The idea of making a panhard bar as long as possible is to minimize the side movement from the arc. The bar on my sedan mounts to the left frame rail to a bracket to the right side of the pumpkin, making it a little longer than half the distance between the frame rails. Since it is level at normal ride height, there is very little arc throughout the range of suspension travel.

1971BB427 01-08-2013 06:46 PM

A panhard bar will fight the leaf springs as the rearend travels up and down. Even in a perfect scenario where the panhard is mounted dead level at the middle of it's travel, it will still try to push the leaf springs sideways as the rearend moves up and down. Leaf springs are not meant to bend sideways, so either they will need to flex in a direction they're not designed to flex, or the panhard bar will try to push the frame, or bend.
Stick with a swaybar for your leaf spring rear, and forget the panhard on a leaf spring rearend.

NEW INTERIORS 01-08-2013 10:16 PM

Adding a panhard bar to a parallel leaf spring set up is a waste of time if you ask me..:nono: They just don't go together.. But if you want to add it.. That's you.. If you have that much play in your leaf springs.. You need to start checking your bushings ...

jaw22w 01-10-2013 07:40 PM

Quote:

Originally Posted by NEW INTERIORS (Post 1632515)
Adding a panhard bar to a parallel leaf spring set up is a waste of time if you ask me..:nono: They just don't go together.. But if you want to add it.. That's you.. If you have that much play in your leaf springs.. You need to start checking your bushings ...

X2. Totally agree!!!!

Too Many Projects 01-12-2013 08:58 PM

I once saw a parallel panhard setup that eliminated the arc bind but can't find any pics now. It had a bar attached to both frame rails. The bars then attached to a vertical fulcrum lever that had a center pivot. The center pivot attached to a bung welded on the center of the rear axle cover. As the suspension moves thru it's travel the bars move the fulcrum lever instead of binding up.
Anyone remember seeing this setup and can scrounge up some pics ??
Found it, it's known as a Watt's Link. Here's an illustrative pic.

http://www.avsontheweb.com/images/P/...C61-C71-01.jpg

gow589 01-13-2013 07:39 AM

That's called a Watts Linkage.

lakeroadster 01-13-2013 06:58 PM

Quote:

Originally Posted by gow589 (Post 1634211)
That's called a Watts Linkage.

And it's way over complicated for 9 out of 10 applications it is used on. Putting all the lateral side loads through the bolts that hold the rear differentail cover on seems quite silly, IMO. Not to mention the example shown above uses heim joints, which transmit all the suspension road noise from the suspension right up into the frame and into the vehicle.

Unless your building a road race truck, keep it simple. And even if you are, NASCAR uses a copy of our truck arms, the same basic set-up used on '63 thru 72 trucks.


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