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Panhard bar interference

11K views 62 replies 9 participants last post by  1971BB427 
#1 ·
:) Took my deuce on its maiden voyage and all was fine except every now and then I heard a clunk noise :( (something like a tailpipe hitting the frame). When I inspected the car underneath I saw the panhard bar which is attached to the 9" diff. by a bracket (bolted on). It was barely 1/2" away from the floor and there was evidence of scrapes and dents in the floor. I cannot cut the floor away as it is in front of the rear seat. This is a TCI frame, 9" Ford diff with coil overs and a '32 Ford tudor. Has anyone an alternative or suggestion that I may use to change this problem? Shortening the bracket (bolts to diff.) that the bar bolts to is almost an impossibility as it is very short in height. Mounting the bar in a different position may be the answer, but the coil overs can get in the way. The frame also has a torsion bar that runs from side to side, which is also hooked to the rear end (stabilizer bar?). Suggestions anyone?
 
#5 ·
My panhard bar has the bracket which mounts on the top bolt of the pumpkin and 1 away from that, nothing like yours. I'm wondering if the bar (19 1/2" long) can be shortened 4 1/2" and take the brackets and mount them on the right side of the diff. As it stands now, the bracket is on the other side which places the panhard above. On the other side the panhard lowers by about 1 1/2", but the bar would now be 15" long. I know that they should be as long as possible, but in this situation it is impossible. Picture of the bracket as shown.
 

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#8 ·
Before you cut your panhard bar, try swinging a piece of tubing/wood/whatever cut to the shorter length along the arc that your suspension travel would allow and see how much side-to-side movement you'd get. You can minimize the side-to-side by making sure the panhard bar is level in the middle of the suspension travel at ride height. Make sure if you move the panhard mount on the frame, that it doesn't interfere with your suspension (lowering where it mounts on the differential would likely dictate lowering it at the frame).
 
#12 ·
It does look exactly the same. Notice the two holes close together look the same too, maybe it's simply designed to mount in either position.....depending on your clearance.

Brian
 
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#13 · (Edited)
No it mounts on the pinion support, if you pull up totalcostinvolved.com and go to '32 Ford chassis you'll that this is the correct location. Also 27, make sure the panard bar is parallel to the ground at ride height so it can work properly. I really don't know how....if 27 did, hook up the panard bar to the top of the 3rd member housing. The mounting loc tab welded to the chassis is installed directly across (inline) with the pinion support, unless he used some kind of spacer (s) or ????. I think the second hole is for an 8" rear. Here's another picture.....
 

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#14 · (Edited)
1. The Panhard bar needs to be as long as possible. Bars mounted to the pinion are a bad joke.
2. The Panhard bar does not need to be a straight bar. It can be twisted up like a pretzel to miss other components on the car and still do its job properly.
3. Panhard bar mounting points need to describe a line that is parallel with the road surface at rest.
4. History would have been much better off if Rene Panhard had been padlocked to a pole and caned until he came up with a better design for preventing lateral movement of the differential housing. James Watt had come up with a much better design by 1808, so Panhard had reference to that to work with.
 
#20 ·
1. The Panhard bar needs to be as long as possible. Bars mounted to the pinion are a bad joke.
2. The Panhard bar does not need to be a straight bar. It can be twisted up like a pretzel to miss other components on the car and still do its job properly.
3. Panhard bar mounting points need to describe a line that is parallel with the road surface at rest.
4. History would have been much better off if Rene Panhard had been padlocked to a pole and caned until he came up with a better design for preventing lateral movement of the differential housing. James Watt had come up with a much better design by 1808, so Panhard had reference to that to work with.
:welcome: Okay 327 I have the panhard coming to a bracket that is mounted on the top bolt of the pumpkin and the one beside it. It has to go there because TCI welded the other bracket end to the frame directly in front of the axle just inches before the cutouts for the axle. And yes it does stick up above the housing. That's why I have the problem. What I'm doing is making a new bracket to mount off the pumpkin and down on the passenger side. Then I plan to cut the bar (made of tubing), extend it with steel rod and then bend it down to meet the bracket on the lowered side. I would love to get better pics, but there is no room for the camera because of the exhaust, mufflers, and driveshaft being in the way.
There may be a problem with your plan as you will be breaking the rule Techinspector pointed out. The end of the rod goes thru an arch, right? Well if you start then them level, unless you have a mile of movement it stays within an area of that arch that doesn't effect the side to side movement.

But if you have one mounting point a lot lower than the other as the axle goes up it's going into that arch, pushing the rear end side to side. You want it as even as possible. You can see that horizontal movement in the illustration below.

Brian

 
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#15 ·
LOL, good stuff and I agree with all of it. :thumbup:

However better the Watt's link is, it's a little too clumsy for most cars and a long Panhard bar is a good way to go.

Brian
 
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#18 · (Edited)
However better the Watt's link is, it's a little too clumsy for most cars and a long Panhard bar is a good way to go.
Brian
That's my whole point Brian. You're correct, the Watt's Link is a clunky device that needs more room to work properly. So, what's the problem with providing more room for it? Isn't that what hot rodders do?

Further, you are correct again when you say that a LONG Panhard bar is a good way to go if there is unsufficient room for a Watt's Link in a platform that is already built. Emphasis on LONG, not some Fosdick short POS that will jerk the diff/body side to side on every bump. Proper design of the bar would find it's length limited only by what will fit in between the brake drums/discs, with one end anchored to a mount that comes down from the frame member and the other end anchored to a mount that comes off the differential housing close to the brake drum/disc. Again, the bar does not have to be straight, as long as it has sufficient material strength to resist the lateral movement of the differential housing.
 
#16 ·
Hey Tech....do you ever have anything positive to say about anyone's project? I'm only a few years behind you but it seems that the older you get the more critical you have become. These aren't race cars you know and TCI has probobly several thousand 28-34 chassis out on the road with this set up w/o any known problem to me anyway......GEEEEEZ
 
#17 ·
If something is done properly from a good engineering standpoint, I'm the first one to say so and congratulate the builder.
There is a right way to do things and there are many wrong ways to do things. I simply point out the proper ways to do things and if that riles you up, then you'll just have to get riled up. The fact is that I see more and more fosdick operations involving malfunctions due to fractured backyard engineering than I used to. Right is right and wrong is wrong and there ain't no middle ground. It's either a weak-suck operation or it's well-built according to good engineering principles.

You want to know how bad it is? It's so bad that I won't even go to amateur car shows any more. All that is there is a parking lot full of bad engineering that is not pleasant to look at.
 
#19 ·
:welcome: Okay 327 I have the panhard coming to a bracket that is mounted on the top bolt of the pumpkin and the one beside it. It has to go there because TCI welded the other bracket end to the frame directly in front of the axle just inches before the cutouts for the axle. And yes it does stick up above the housing. That's why I have the problem. What I'm doing is making a new bracket to mount off the pumpkin and down on the passenger side. Then I plan to cut the bar (made of tubing), extend it with steel rod and then bend it down to meet the bracket on the lowered side. I would love to get better pics, but there is no room for the camera because of the exhaust, mufflers, and driveshaft being in the way.
 
#21 ·
Since you can't post any pics I can't give further info or recommendations.....but I would contact TCI and tell them what problems you're having.....I also STRONGLY suggest NOT to use a "metal rod" of any length. Thick wall tubing is much stronger, find a piece of chrome molly or even DOM. I would first call TCI before I did anything. That was a good post Brian but remember these street rods have very little rear end up and down movement, 2-3 inches at most. I think that's why they can get a way with a shorter panhard bar.
 
#22 ·
You are very correct, it doesn't move much, but with the difference in height on the mounting points, it can be pretty drastic depending on how much of a difference there is. And often the tires are close to the body, just a little bit and they are hitting. I am just tossing out general geometry info, how it pertains to his exact car is up to him. Being we are so limited with what it all looks like, that's all we can do.

Brian
 
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#23 ·
To clarify - the panhard bar can bend all over the place, like Tech said, but it's the mounting points that should be level at ride height. Adding angle between the mounting points will add movement side-to-side, but it will also load the suspension unevenly as it moves vertically. That loading is why the NASCAR guys use panhard bars instead of a watts link which loads evenly. It also affects roll center which a watts does not.
 
#24 ·
To clarify - the panhard bar can bend all over the place, like Tech said, but it's the mounting points that should be level at ride height. Adding angle between the mounting points will add movement side-to-side, but it will also load the suspension unevenly as it moves vertically. That loading is why the NASCAR guys use panhard bars instead of a watts link which loads evenly. It also affects roll center which a watts does not.
That is true with an oval track car which only takes left hand turns, but a car running road courses I would imagine uses the Watt's.

Brian
 
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#26 ·
:) I cannot cut the floor away as it is in front of the rear seat. Suggestions anyone?
Hmm.. I am thinking you'd be wise to cut a hole in the floor then make a cover that bolts from the top. It won't be much of a hump to give you the clearance you need and you can leave the suspension alone.

As has been stated previously, when it comes to panhard bars, much like other useful tools, longer is better. :thumbup:

Hope that helps. Good luck to ya.
 
#27 ·
:welcome: Carefully weighing all the options, but as I stood staring at the problem I noticed that the torsion bar(?) which runs parallel to the axle, from behind, and has arms linked to it is also hitting the floor (the attachment point). I've run out of adjustment on the sleeve and so am wondering whether I can shorten the attachment link by about 3/4" which would put it closer to the axle, but the arms will will not be parallel to the ground (would this be a problem?). Presently the arms are 1 1/2" above the axle and I can get a finger between the floor and the connecting link (at the end). The floor pan is still original and this is causing all the problems.
 

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#29 ·
Those links have very little to do with any suspension movement geometry. In fact, you could take that sway bar out completely, just remove it and the car would drive possibly very near the same as it does right now. So shortening them isn't a big deal.

But you need to step back and look at this, is modifying the floor a better idea? Give clearance to everything and it's a done deal. But do take more photos, get it up on a lift or something so you can step back and take a good look at this.

Brian
 
#30 ·
Have it on a hoist and extremely difficult to really see the clearances as you are looking up at the problem instead of directly at it. Can only see a bit at a time with a mirror as the mufflers, driveshaft etc. are in the way. My last photo shot was when I jammed the camera at one end and kept shooting until I had a decent picture portraying my latest problem (couldn't see the view finder). I think the only solution is to recut the floor (cut it to clear the banjo housing). I find that TCI puts out a good product, but they need to do more suspension engineering. Another instance was when I had to cut the front fender supports to clear the independent suspension!! Why they didn't widen the stance to clear the brackets is beyond me.
 
#31 ·
Have it on a hoist and extremely difficult to really see the clearances as you are looking up at the problem instead of directly at it. Can only see a bit at a time with a mirror as the mufflers, driveshaft etc. are in the way. My last photo shot was when I jammed the camera at one end and kept shooting until I had a decent picture portraying my latest problem (couldn't see the view finder). I think the only solution is to recut the floor (cut it to clear the banjo housing). I find that TCI puts out a good product, but they need to do more suspension engineering. Another instance was when I had to cut the front fender supports to clear the independent suspension!! Why they didn't widen the stance to clear the brackets is beyond me.
Because the control arms would have to be too short to keep the tires from hitting the fenders. And by the way on that floor, I am thinking you take it all the way off from the side supports to the rear body panel, to over the rear end, the whole thing, replace it with one that gives you more clearance. I am thinking this would very possibly be the easiest way to handle this. Without a bunch more photos it's kinda hard but take a look at this idea and make your choice.

Brian
 
#39 ·
Tech, You were the one in this thread with all the attitude. My suspension was designed by Pete & Jakes, and uses a panhard bar from the frame rail to the far side of the pinion support - similar to the TCI design - too short and lousy engineering by your statements. I checked the side to side movement throughout my suspension travel (which is very short like a lot of '30s rods). My bar is level at ride height. The side to side movement is about 3/16" as the suspension cycles from center to the top, and from center to the bottom. A panhard bar works quite well in this application.
 
#51 ·
Tech, You were the one in this thread with all the attitude.
I guess I do have an attitude when I see CRAP engineering being foisted off on fellows who apparently don't know the difference between crap and good engineering practices that will provide minimal lateral movement.

My suspension was designed by Pete & Jakes, and uses a panhard bar from the frame rail to the far side of the pinion support - similar to the TCI design - too short and lousy engineering by your statements. I checked the side to side movement throughout my suspension travel (which is very short like a lot of '30s rods). My bar is level at ride height. The side to side movement is about 3/16" as the suspension cycles from center to the top, and from center to the bottom. A panhard bar works quite well in this application.
If you're happy with it, that's great, but I don't want the body of my car moving laterally by even 3/16ths of an inch if I have the wherewithall to make it less than that. I think some of the fellows on here are getting snotty because they have spent money on CRAP and they don't like me bringing it to their attention because it makes them look stupid and nobody wants to be made to look stupid in front of 120,000 car nuts.
 
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