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The below guide is going to show you how to set up a double adjustable panhard rod on a 1993-2002 F-body. If you have a stock suspension setup Camaro or Firebird and have taken a look under the back end, you've probably notice the non-adjustable steel stamped panhard rod that stretches from one side of the car to the other. The purpose of this bar is covered pretty clearly here: Sam Strano on the 4th Gen suspension and Chassis
It is not a weak piece by any means, but there is merit in changing the panhard rod when you have lowered the vehicle or are running a bigger tire; both of which will throw off the geometry of your suspension. To be clear, before you change your panhard rod I would suggest going through step 6 below first to check if you even require the bar to begin with. If your measurements are way out of whack you know you require one.
This guide covers replacing and adjusting the bar for those that need to do so.
Step 1) You will need to jack the rear of the car up and put it on jack stands without having a load on the axles. Since most of us do not own a lift at our disposal that means a jack and jack stands. I put a jack under the pumpkin of my rear diff and lift from there. Since I do not want any weight on my axle (as I will need to be moving it from side to side) I put my jack stands on the rear frame points. Please make sure you chock the tires at the front and be sure that the car is secure on the stands before getting under it. I can't stress safety enough here.
Step 2) You will see there is a nut/bolt on each side of the car holding your panhard bar in. A breaker bar/wrench or an air gun/wrench makes quick work of these two bolts. Once these are off the panhard rod will come right out. At this point your rear axle may shift left/right as the panhard rod is what holds the rear end centered. As long as the rest of your suspension is bolted up it the rear end won't go very far.
Step 3) Take your old Panhard bar out and measure it from end to end for a starting point. In the picture below I had to take my aftermarket panhard bar out to replace the rod joints. By measuring the length of the bar that was installed prior to, I can make sure I set the replacement panhard rod close in length to cut my work out for me. Since I have a double adjustable panhard rod I can adjust my rod on the car without having to unbolt it each time - which considerably cuts down on adjustment time. If you have a double adjustable bar like me, loosen the collar nuts on either end of your rods so that you have lots of adjustable room to work with. You can tighten these later (you could loosen them as you need as you go to, but to me this is just easier). The way this bar works is once it is bolted into place you put a wrench on both ends of the middle pipe on the collars and turn the middle pipe. As it moves to the left it will pull the axle with it, as you move it to the right it will pull the axle the other way.
***If you have a single adjustable panhard rod you will need to unbolt the side that is adjustable (non solid side) from the car each time you need to make an adjustment - turn the head on the body of the solid part of the panhard rod and bolt it back up to recheck your measurements. You would repeat this until it you have your desired measurements.
Step 4) Reinstall the new panhard rod where your stock on went. I like to attach the top bolt first and hand tighten it. I then slide myself over to get the bottom rod eye lined up so I can put the bolt through. Since the axle will have shifted at this point you will need to look at how your bolt hole isn't lining up to figure if you need to push the axle towards the driverside or passengerside. If you have a helper they can push on either of your tires for you to help you line it up. If you work on your own like me, I just use my legs to push on the tire wall from underneath to move my axle over and line up my bolt with the hole through the frame / rod eyelet. Once that bolt is in I snug up the bolts on both sides and torque them down.
Step 5) Grab your jack and put it under the pumpkin of your axle. You need to have your suspension loaded in order to get accurate readings. If you jack the axle up (not so it takes the car off the jack stands) but so that the axle is loaded almost to the point where you are ready to lift the car you will ensure your measurements are more accurate. I loaded my suspension up like so:
Step 6) Since your measurements to your old panhard rod aren't going to be 100% accurate you're going to come out from under the car and grab your plumb. Set your pump up hanging off your fender and let it hang down. If you don't know what a plumb is, this is what it looks like and can be picked up at pretty much any hardware store for fairly cheap.
Don't let the plumb touch the ground, but let it hang about a half inch off of it for the most accurate results. Since I am working on my own and it is hard to measure and hold a plum I used some painters tape to hold the string to the fender. I then measured from the flat part on my rim which can be the center or lip in my case to the plumb of the string and wrote down my measurement. You want to make sure you are measuring from the exact same point on both sides of the car or your numbers will be incorrect.
After you do this for one side you are going to take your plumb and do the same for the other wheel.
If you are 5" for example on your driver side wheel and 6" on your passenger side wheel (from the plumb string to the center of your rim face) you know that you need to move the axle ½" towards the driver side in order to even things out.
Check how much you are out, release the tension on your jack and turn your panhard rod. The rod does not need to be spun much to see results. Remember, for every inch you take away you are adding to the other side. So adjustments happen quickly. Keep doing this until you get your desired result of symmetry.
An important thing to remember here is that when you put the car down on pavement and load your suspension fully you will need to recheck your measurements. You may need to tweak your panhard rod a touch more. The reason for this is sometimes it isn't always possible to fully load the rear suspension by jacking up the rear axle. All in all it does not take too long to get the measurements perfect.
Another thing to note is even after adjusting your panhard rod you may still need a BFH to hammer out your wheel wells if your tires rub. Every combination of tires/wheel offset creates a unique situation that has caused some folks to rub and others to not. Make sure if you need to adjust your panhard rod a particular direction you are checking to make sure that your tires are not rubbing under load preventing you from seeing results. Each time you make an adjustment check for clearance with the suspension loaded.
Make sure that once you get the measurements spot on where you want them, go back under the car and tighten the collars down on either side of the panhard rod pipe. If you do not, vibrations from driving will vibrate the pipe and throw your rear end out of whack.
It is not a weak piece by any means, but there is merit in changing the panhard rod when you have lowered the vehicle or are running a bigger tire; both of which will throw off the geometry of your suspension. To be clear, before you change your panhard rod I would suggest going through step 6 below first to check if you even require the bar to begin with. If your measurements are way out of whack you know you require one.
This guide covers replacing and adjusting the bar for those that need to do so.
Step 1) You will need to jack the rear of the car up and put it on jack stands without having a load on the axles. Since most of us do not own a lift at our disposal that means a jack and jack stands. I put a jack under the pumpkin of my rear diff and lift from there. Since I do not want any weight on my axle (as I will need to be moving it from side to side) I put my jack stands on the rear frame points. Please make sure you chock the tires at the front and be sure that the car is secure on the stands before getting under it. I can't stress safety enough here.
Step 2) You will see there is a nut/bolt on each side of the car holding your panhard bar in. A breaker bar/wrench or an air gun/wrench makes quick work of these two bolts. Once these are off the panhard rod will come right out. At this point your rear axle may shift left/right as the panhard rod is what holds the rear end centered. As long as the rest of your suspension is bolted up it the rear end won't go very far.
Step 3) Take your old Panhard bar out and measure it from end to end for a starting point. In the picture below I had to take my aftermarket panhard bar out to replace the rod joints. By measuring the length of the bar that was installed prior to, I can make sure I set the replacement panhard rod close in length to cut my work out for me. Since I have a double adjustable panhard rod I can adjust my rod on the car without having to unbolt it each time - which considerably cuts down on adjustment time. If you have a double adjustable bar like me, loosen the collar nuts on either end of your rods so that you have lots of adjustable room to work with. You can tighten these later (you could loosen them as you need as you go to, but to me this is just easier). The way this bar works is once it is bolted into place you put a wrench on both ends of the middle pipe on the collars and turn the middle pipe. As it moves to the left it will pull the axle with it, as you move it to the right it will pull the axle the other way.
***If you have a single adjustable panhard rod you will need to unbolt the side that is adjustable (non solid side) from the car each time you need to make an adjustment - turn the head on the body of the solid part of the panhard rod and bolt it back up to recheck your measurements. You would repeat this until it you have your desired measurements.
Step 4) Reinstall the new panhard rod where your stock on went. I like to attach the top bolt first and hand tighten it. I then slide myself over to get the bottom rod eye lined up so I can put the bolt through. Since the axle will have shifted at this point you will need to look at how your bolt hole isn't lining up to figure if you need to push the axle towards the driverside or passengerside. If you have a helper they can push on either of your tires for you to help you line it up. If you work on your own like me, I just use my legs to push on the tire wall from underneath to move my axle over and line up my bolt with the hole through the frame / rod eyelet. Once that bolt is in I snug up the bolts on both sides and torque them down.
Step 5) Grab your jack and put it under the pumpkin of your axle. You need to have your suspension loaded in order to get accurate readings. If you jack the axle up (not so it takes the car off the jack stands) but so that the axle is loaded almost to the point where you are ready to lift the car you will ensure your measurements are more accurate. I loaded my suspension up like so:
Step 6) Since your measurements to your old panhard rod aren't going to be 100% accurate you're going to come out from under the car and grab your plumb. Set your pump up hanging off your fender and let it hang down. If you don't know what a plumb is, this is what it looks like and can be picked up at pretty much any hardware store for fairly cheap.
Don't let the plumb touch the ground, but let it hang about a half inch off of it for the most accurate results. Since I am working on my own and it is hard to measure and hold a plum I used some painters tape to hold the string to the fender. I then measured from the flat part on my rim which can be the center or lip in my case to the plumb of the string and wrote down my measurement. You want to make sure you are measuring from the exact same point on both sides of the car or your numbers will be incorrect.
After you do this for one side you are going to take your plumb and do the same for the other wheel.
If you are 5" for example on your driver side wheel and 6" on your passenger side wheel (from the plumb string to the center of your rim face) you know that you need to move the axle ½" towards the driver side in order to even things out.
Check how much you are out, release the tension on your jack and turn your panhard rod. The rod does not need to be spun much to see results. Remember, for every inch you take away you are adding to the other side. So adjustments happen quickly. Keep doing this until you get your desired result of symmetry.
An important thing to remember here is that when you put the car down on pavement and load your suspension fully you will need to recheck your measurements. You may need to tweak your panhard rod a touch more. The reason for this is sometimes it isn't always possible to fully load the rear suspension by jacking up the rear axle. All in all it does not take too long to get the measurements perfect.
Another thing to note is even after adjusting your panhard rod you may still need a BFH to hammer out your wheel wells if your tires rub. Every combination of tires/wheel offset creates a unique situation that has caused some folks to rub and others to not. Make sure if you need to adjust your panhard rod a particular direction you are checking to make sure that your tires are not rubbing under load preventing you from seeing results. Each time you make an adjustment check for clearance with the suspension loaded.
Make sure that once you get the measurements spot on where you want them, go back under the car and tighten the collars down on either side of the panhard rod pipe. If you do not, vibrations from driving will vibrate the pipe and throw your rear end out of whack.
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