Here's the basic layout of our 48 DeSoto 4dr build: #1) It's a low $ traditional build for a couple in their 60's who want to build an old car to drive around the County. #2) 68 New Yorker 350 horse 440 bone stock with no performance up grades other than an Edelbrock intake & 4 bbl. HEI ignition & ceramic coated (motorhome) center dump manifolds. #3) 727 Torqueflite & an 8 3/4 rear with 3:55 gears. #4) Jim Weimer Rod Shop front clip (Mustang II architecture) with GM metric calipers, 11" rotors & T Bird rack & Pinion steering. Mustang II 6cyl front springs. #5) OEM 15" wheels widened to 7" for better rubber & the ability to run OEM hubcaps. Now that you have the background, see if you come to the same conclusion I have with the rear suspension: This vehicle came from the factory with parallel rear leaf springs. Believe it or not, it also came with a panhard bar. To make matters more of a challange to understand, the rear shocks did NOT mount from the spring perches toward the center of the car, they actually ran FORWARD toward the front of the car into the frame arch over over the rear axle. Depending on which side you viewed they would be at 10 o'clock or 2 o'clock. I found this whole arrangement beyond my understanding and ditched the OEM shock layout for a conventional layout across the car toward the center. This resulted in a fabricated shock crossmember. The only reason I can figure a panhard bar from the factory is that the OEM rear springs are only 1.75" wide and they might have a tendency to wrap up on corners. That coupled with the weird OEM shock layout and a high center of graity must have made cornering above 20 MPH a challenge. We are considering a set up Posie super slide rear springs for the car. When I spoke with their tech people, the response was "Factory engineers were doing some strange things in the 40's with suspensions. Our suggestion is to dump the panhard bar and go with a new set of springs." Myself, I'd just feel better if the rear springs were more of the conventional 2 1/2" wide instead of 1 3/4". Personally, I just can't see why the panhard bar should stay, much less why it was installed. I do plan on installing a sway bar, but the panhard bar strikes me as "WTF?" Again, this is a long distance cruiser that my wife & I plan on seeing the Country with. I figure the finished weight to be in the neighborhood of 4,600# wet. The Weimer front end & Posie rear springs will lower it about 2 1/2" from OEM height, but I'm still going to use a 29-30" tall tire. It will still have a high center of gravity, but I do want a quality ride from it. Anyone agree or disagree with the Panhard bar issue? Please advise.
My opinion-shock angle isn't really going to matter-if they're leaning forward 20 degrees or in 20 degrees it will be about the same. If i stayed with the stock springs I'd keep the panhard bar, if I went aftermarket on the spings I'd lose it. My thought is the stock suspension must be designed with enough sidways play that the it will allow the movement needed with the panhard bar.
You have changed the 60 year old front suspension for something more modern. You have change the brake system for something more modern. You have changed the drive train for something more modern. You have even changed the wheels. You didn't feel a need to ask us about those changes, why are you now questioning keeping the original rear suspension???????? Put the modern springs and the modern shock setup in, and give the original parts to someone that is interested in keeping their car original. Forget that original rear suspension and enjoy your car. Gene
The intent of my question was trying to figure out the necessity (?) of the panhard bar. Did anyone else question the factory use of it. My feeling is that a panhard bar locates the rear axle in much the same way as a Watts linkage but without the fine adjustments of a Watts. I always thought that vehicles with parallel leaf springs did not REQUIRE a panhard because the axle self centering. The only reason I could come up with such useage was the possibility of the (narrow) wrapping up at just below the spring eyes, thus allowing the axle to travel sideways. If that supposition is true, and if Posies sells a replacement spring that is the same width (1.75"), why would a new spring of the same dimensions be any different? The only reason I included the other changes to the vehicle was to give you an idea of what the car encomp***es, I am asking for input not "asking for a need to keep the rear suspension." I just want a good ride out of this behemouth.
You shouldn't need a panhard bar but it certainly isn't hurting anything unless it is in the way of your different shock setup. If you are running a sway bar that should cure body roll which may have been what the panhard bar was supposed to help deal with anyway. So either way keep it loose it either will probably be OK.
A panhard bar seems to be a wierd way to control wrap-up, but I've heard of wierder. With modern multi-leafs and metalurgy, I'd say it's safe, but don't cut the links until you know....
The intent of the panard bar was to lower the roll center on turns. With that huge car I would run the bar at or lower than the center line of the rear axle.
Not what you asked, but...unless Posie is giving the springs away I'd be looking for oem Mopar springs from a B or C body. More than adequate for the job and very few leave the local pik-n-pull through the front gate. Oem springs and sway bar will do everything you describe needing done. .
The panhard rod is probably a carry over from the Comercial Vehicle ch***is. Remember Desoto were the NYC taxi cab in the 40's along with checker. the panard rod probably kept the fenders from rubbing the tire in turns with 5 or 6 p***engers and their luggage in the car. Some Mopars of that era had rear anti sway bars, some had panhards and some had nothing but spings. My plymouth only has the skinny rear springs but there are 8 of them (9 on the drivers side) So they made up for width with extra leaves springs. Sure there was a bit of body lean in just about every car made, and especially with the fords that kept thier buggy spring till 49, so it probably wasn't a concern. Remember average road speed was probably 40, and less in the city so cornering G's were less of a concern than sofa style comfort. I have kept the stok suspension on my coupe and don't reall have a problem. My wife does sometime as my delux coupe doesn;t even have arm rest for her to grab onto if I get a little agressive on the corners.
I think your questioning of the original shock installation deserves re-visiting. It is true that when a shock is tilted from verticle it's travel is reduced (for a given amount of axle movement) and it's damping effectiveness may be reduced unless it's stiffness is changed accordingly. However, I would think that shocks angled forward as you describe would be more effective at resisting roll in turns than would shocks angled inboard at the top. It's a matter of travel and leverage to some extent. If the shock is outboard on both the axle and frame it will be at it's most effective position to resist body roll. I do agree with your ***essment that the Panhard Bar was probably included because of the relatively small crosssection of the rear spring leaves and perhaps the shackle and bushing stiffness (or lack thereof). Given the rather bulbous, high center of gravity of the body, I would think the MOPAR engineers where correct to add the PB to maximize rear axle control. In the 40's and 50's it was pretty damn difficult to to find cars that rode and drove better than Chrysler products. Ray
I was going to give you my two cents and until I found that Hnstray already did. hit the nail right on the head. Many, many vehicles left and still leave the factory with forward (or rearward) leaning shocks.
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