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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
 

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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
 

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Hot Rods are Built, not Bought
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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?
 

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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.
 

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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:




 

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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.
 

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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.
 

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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 ...
 

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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.

 

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Hot Rods are Built, not Bought
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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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Yes, poly bushings will definitely stop deflection. Aluminum will also, but it will transfer too much road noise to the body, and you'll get tired of that quickly!
I put poly bushings in my front control arms, body bushings, and rear spring bushings, and it really stiffened the suspension up on my '71 Camaro. I also added HD swaybars front and rear, lowering springs all around, and Lakewood ladder bars in the rear. It handles like a slot car after that.
 

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would stiffening the rear bushings reduce deflection in turns? I've got rubber now, would moving to aluminum or poly be a good idea?
The beauty of rubber bushings in a leaf spring set-up is that they do distort and deflect. When you go over a one wheel bump or when you are cornering and have body roll, the rubber bushings allow the rear suspension to twist slightly and not bind. If you replace the rubber bushings with polyurethane or aluminum or delrin or any other stiff material you have compromised the ability of the axle to "twist" in one wheel bumps. Stiff bushings are not a problem when both wheels hit a bump at the same time (speed bump for example) or if the car is used mainly for drag racing, but for the street, keep good rubber bushings in there.

If you want to get rid of that flexing feeling while cornering, but still want compliance in the rear suspension, then install a panhard bar as I described in an earlier posting. It will help also if your tires rub while cornering.

Regards,

Andy
 

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There will be no binding action w/ stiff bushings. In the event of body roll or hitting a bump w/ one wheel etc., leaf springs simply twist. It's part of what they are made to do, and the reason why a leaf-spring car doesn't need much rear sway bar...the leafs are already (by design) providing roll resistance by twisting. (In fact you might save the weight/cost of having to use a rr bar by using stiffer bushings, depending on your setup.)

Binding is what happens when you have two conflicting types of suspension links working against each other...which you may or may-not end up with here, depending on who's advice you are going with...;)

The downside of stiff bushings is increased transfer of vibration and spike loads into the mounts which may become more prone to cracking, and of-course noise...for that reason I would hold the line at plastic and not go any stiffer.
 
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