Hi guys. I’m in the process of having some new parts welded to my A frame. This question is regarding the rear panhard bar. As for starters, it’s a stock model a frame, that’s been boxed, and I have four link suspension in the front and rear. At some point, the original owner had some Chevy 10 bolt rear end, and the rear crossmenebr was stock, and the standard 90 degree angle panhard bar bracket is on the frame. When I bought the car, at some point someone changed the rear end to a ford, and did the appropriate new rear crossmember to “avoid-the-ford-rear-end.” The problem is, the 90 degree bracket for the panhard bar wasn’t used, due to how further back the new rear cross member was welded / currently is. They did a hole (and I bought some brackets to weld there if it’s a good option) at the top of the new rear cross member, which the current way the panhard bar is, at a 45 degree angle. MY OVER-ALL QUESTION Can I (of course I would weld my new bracket first) keep my 45 degree angle for the rear panhard bar? OR SHOULD I do the adjustments and just use the 90 degree angle mount? Is one better than the other? Does it matter? Is performance a part of it? Let me know guys. Thank you to those who read it all and respond.
I believe the Panhard bar needs to be as close to horizontal as possible at ride height, in order to minimize the amount the diff moves laterally when it moves up and down over bumps, etc.
You need a weldment that goes on the rearend housing similar to the one on my roadster. The panhard bar needs to be as long as you can get it in the available space and as close to level as you can get it, also, the panhard bar does not need to be perfectly straight. You can then drill a new mounting hole somewhere down the angled leg of that square tube crossmember for your panhard attachment. Accept the fact that a new bar may need to be made/purchased and some reengineering and fabrication done for a more ideal setup. You also may want or NEED to change the brake line/hose setup.
No, that has to go. I wonder if they ever actually drove it like that. Don't like the upper shock mounts either. I'd remove the current crossmember and build a setup similar to the pic DDDenny posted with the crossmember behind the axle.
That coil over mount way out appears to be poorly engineered as is the panhard bar that needs to be on a shallower angle to work correctly. A longer bar and arc are required. I'd suggest cutting it all out and starting from scratch. A new rear cross member and set the wheelbase correctly. Also set up the panhard bar and rear shocks. Here are local requirements for 4 bars in our builds:- Front 4 bars: Up to 900mm long, tube OD 22mm, wall thickness 3mm, 5/8" UNF or 16mm fine (Metric) Rear 4 bar (Normal duty) Up to 900mm long, tube OD 22mm, wall thickness 3mm, 5/8" UNF or 16mm fine (Metric) Rear 4 bar (Heavy duty): Up to 900mm long, tube OD 25mm, wall thickness 3mm, 3/4" UNF or 19mm fine (Metric) Lots of little things to factor in or consider. Do it once, do it right at the outset, you'll thank yourself later when you're driving.
That'll have a HORRIBLE sideways movement when the suspension moves. For every inch the suspension moves, the axle will be moved about an inch sideways. If you want the car to go zig zag through every bump it's probably a great design. Might even be so bad you lose grip.
Thank you for the info. I’m going to copy yours. I found something very similar to yours on ebay I can buy. Thanks very much sir!
Here is a link to a video that explains a lot in a short time. I tried to go back to Geometry school and show the same info with the numbers, but it would probably take me days! Long story short, long bar with correct geometry is ideal, BUT.... better to have a short bar and correct geometry than a long bar with incorrect geometry. The Panhard bar on the rear of my car doesn’t have optimal length or geometry (close and close), but the car handles fine on the road. John Watch this:
I realize this is not what is on your mind at this point but the adjustable bars are great for getting the body centered over the tires and will correct for differences in ride height.
While you are at rebuilding everything, you will need to make the radius rods stronger/bigger if you have over 200 hp. Remember, they not only need to handle the driving torque on the axle but they also drive the car forward.
I can see a couple of issues with that setup that will make it not be an optimal arrangement. The biggest issue is the angle, which will kick the rearend to one side whenever the suspension compresses. But the short length compounds the effect, and it should be much longer. Simple fix is to lower the mounting point on the crossmember so it's as close to level as possible. Better fix would be to mount a new bracket welded to the opposite side on the axle tube, and raise it up so a longer panhard bar would work, and be closer to level. This is a setup I built for a friend's coupe:
The Jalopy Journal
