So much preload in rear sway bar I can't get the brackets back on.

I have struggled from time to time with securing the sway bars.  It may not help in your case but I have used much longer bolts to help get the bracket in place.  Once it is seated then I replace the long bolts with the regular ones, one at a time.

Also, you can install the long bolts as studs to help line up the bracket.  Then use nuts to pull the bracket down.

In the ideal case, I would suspect we would want our sway bars to be under very low load levels when the car is at ride height?

They should just bolt right up, or is some level of preload desirable?

I’ll have to sit off “Engineer to Win”, by Carroll Smith!

Rocky

PS…. I generally have a bit of a struggle with my sway bar too…

The 'sphere ball' bushings make that job a little easier.

There can be a clearance issue to the spinning half shaft under suspension compression with the taller hardware used to secure them to the A arm.

You will never get them all aligned and bolted up by fighting the sway bar.

Put the brackets on the a arms and bolt them up to the a arms.  Then use a clamp to  pull the  sway bars back into the body of the car with the sway arm bushings in place. Then slide on the metal U brackets and bolt them up to the fixed studs . Then release the clamp.

There is a post on how best to do this with photos- I will find the reference.

Here are a couple of photos to give you an idea. Its pretty simple.

The longer bolts worked for me. I have the larger rear GTS bar in the rear.

Bosswrench once posted that if you use the larger bar you HAVE to use the ball mounts to keep from tearing the bar mounts loose.

That is something I still need to do. I'd like to hear more about needing to "clearance" things in the rear before I do it.

Here's a question on that subject though that I need to ask while everyone here is paying attention.

If I put calipers on my rear bar, it measures .900". That's not one inch and it doesn't translate to metric evenly. This was a bar from Hall.

The ball kits available are 3/4", 7/8" and 1". Do I get a 7/8" and machine the ball out to match? I presume that the balls are Delrin?

If that ball bracket is too high and will make the bar interfere with the axles, can it be milled down for clearance?

It is my understanding that Mark at ISPCO can make custom balls for whatever size your sway bars are, but double check with Mark.  Also, I have seen some ball joint that the bolts are not countersink in the brackets which could cause clearance issues, but the new ones have the bolts countersink which will help on the clearance.

Thanks guys. @Percy, I'll try your tip. I do wonder why there's so much preload - glad it's not just me.
Does anyone make a sway bar or link the mounts on the bottom of the A-arm?
Getting pretty tight to the exhaust now that I've lowered the ride height a bit.

It is very common for the sway bar to “self clearance” itself from repeated exhaust pipe contact

Not really a big deal, IMHO  

Larry

Jmardy It sounds as though you have a series of parts that don't quite fit together on your car. If you're very sure the bar size, ride height and shock length you now have are what you want to live with for awhile, try sphere-ball outer bar mounts. They noticably improve any anti-swaybar's performance. I use sphere-ball ends  on both front & rear bars to eliminate binding. Hall Pantera and Larry Stock's PPC shop each sell different versions. Finally, try flipping the bar 180 degrees. I've had bars that fit one way but not the other.

The bar end diameter is not much of a problem because the 'balls' in the sphere ball mounts can be bored out to match- if not by you, then by a shop nearby. Just make sure the bar is not somehow oval on it's ends. Some bar mfgrs are a little sloppy assuming the ends are going into bushings. The bar ends should barely slip-fit in the ball. so cut no more than 0.002" max clearance.

And if none of those suggestions work, the bar itself can be re-bent. When I made up my lightweight hollow bars from thickwall 4130 steel tubing. (illustrated article in POCA Archives), I used a cheap hydraulic Harbor Freight exhaust pipe bender to create bars from straight stock. Don't depend on published bar angles- you already suspect your car is a little "different".

Jmardy,  If you don't want to make sway bars, I am having (5) sets made of 1" Solid bars.  They took the stock bars and computer scanned them so I can get it match.  They will be done late February.  Let me know if you're interested let me know.

I had a similar problem with my rear bar - all stock pieces.  When I managed to get it installed, I could see the bar was bending between the chassis mounts by the stress it was under.  I made a spacer for each one, about 6mm thick, and put them behind the chassis mounts, thus moving the center section of the bar rearward.  Now fits fine.  Front was not a problem, go figure.

Good stuff. Thanks for the tip @ufo-low, I will try that.
@Lardog, I'll PM you.

Cheers,
-John

Lube the welded on studs well with penetrating oil and let them sit overnight first before you try to remove the nuts. They snap off very easily. DO NOT use an impact wrench on them. They would be goners for sure if you do.

I noticed long ago that in relation to fender opening heights, the chassis seems to be twisted. All in all though, it doesn't seem to effect handling at all.

I never considered the chassis jig being off. Just looking at the sheet metal suspension mountings makes me think that there is quite a bit of flexing in the mounts to begin with anyway you look at it.

You need to unbolt the bar completely then bolt the rear brackets first to the frame. Put the wheels back on then lower the car to the ground  then bolt the end brackets to the lower A-arms.  

* I just looked at your pictures and your uprights aren’t installed. Please hold off until that is done so you can install the wheels and set it on the ground or so you can put jack stands on the lower uprights.  It makes it a lot easier to install when the bar is at the neutral position.

@liv1s, that's what I tried to begin with. No way to bend the bar out far enough to get the bolts in the bracket. Maybe if I had another set of arms with a breaker bar on the end of the sway bar. I had to unbolt the center chassis mounts, bolt both ends to the A-arms then use clamps to push the chassis mounts forward. Still feels wrong to me.

Not trying to make things worse, but the 'bolts' that hold the central section of the rear bar to the car (and which take ALL of the swaybar weight transferred) are light duty grade-5-at-best. They break regularly and are repaired in various ways. And they aren't plain hex-head bolts. They are weld-on bolts. inside the rear crossmember assembly, the "bolt" heads are round and are spot welded at their periphery touching the crossmember.

So do not try brutalizing a poorly fitting bar. Besides breaking in two, the three tiny spot-welds holding each 'bolt', will crack. If you try drilling a hole thru them to thread & use a stud, the heads break loose and cannot be tightened. The best substitute I found so far for broken fasteners was to drill a large hole in the crossmember from the ZF side, knock out the broken or loose head and substitute a one-size larger grade 8 allen bolt, which can be inserted and tightened thru the access hole you just drilled. If you do this, the central holding clamp holes, of course must be made oversized to match. As mentioned, it is FAR better to re-bend the swaybar to fit the car, than to try to pull the bar in place & risk 'bolt' breakage.

All this comes from the chassis distortion that happens when NOT using an adjustable rear bar-brace above the bellhousing. This subframe twist shows up as excess rear tire camber, and a stock upper brace-bar simply cannot resist this. Large, sticky rear tires on a car driven hard (as it should be!) makes the camber gain and frame distortion progressively worse. There are several POCA articles written (in the POCA Archives) on adjustable upper bay-braces, rear camber fixes and using bigger swaybars in the rear. Some owners fix this permanently by seam-welding the entire rear of the car. The gain in stiffness is reportedly pro-race-worthy. Others make a whole new rear crossmember.

I agree 100% with Bosswrench about not forcing a bar to fit. First of all, ideally, there should be NO preload on a sway bar in any direction. Forcing the bar towards the frame will likely cause some binding at the outer joints as well as the central mounts. A bar should be able to move freely. For example: if you disconnect the bar end from one side of the car and at the other side you remove the shock (with spring) the suspension movement should not be affected by the bar (assuming the suspension bushing are fully compliant). If there is any drag or binding then the anti-sway bar system is not working correctly. The bar spring rate curve will be affected and inconsistent. Imagine going in and out of a binding state while moving through the suspension travel. You probable wouldn't notice it to much in a street car except in extreme cases.

Side to side bar preload will affect the spring rates at the wheels (wheel rate) which is undesirable. Maybe it's good for oval track racing? Ideally the side to side preload should be zero'd out with the car on a flat surface and loaded with driver and fluids. It's close to impossible to get it perfect on a street car but close is much better than not close.

Unfortunately the Pantera anti-sway bar system doesn't allow easy adjustment.

My  view was over time the chassis does flex as pointed out by Bosswrench. The Sway bay keeps its shape but the mounting brackets wear and distort to suit the new rest state of the car.

You pull the whole mess apart- there is no apparent spring in the sway bar . You install new bushes and hardware that have tight original tolerances  and it becomes very apparent how much the chassis has moved.

We are not talking allot here - perhaps a few mm each side , but it is enough to make fitting the bar back into the new no wear clearance supports a challenge when the A arm fixing points are all captive threads. Using  clamps to pull the sway bar back into the rear mounts is very controlled and avoids overstressing all the captive bolts and nuts.

The  clamps are very limited in the force they can apply - nothing like the huge forces generated during exuberant cornering. Any residual force in the sway bar after installation  would be insignificant compared to this.

IMHO.

Thanks for the great discussion.
I'm going to try to find someone with press and will coerce it until it fits nicely. The spherical mounts make a lot of sense too. I do have an adjustable upper brace (from IPSCO) that has been on for a few months. I set it up with just a very slight amount of outward pressure but haven't touched it since.

Thanks for the backup, Percy. Although I don't quite agree with the late Carroll Smith (crew chief on the winning GT-40 team) who when asked by Ford for his rating on the Pantera as a race car, stated "..It is hopeless. The rear suspension is fastened to nothing at all"... It's a bit flexy but not THAT bad.

@bosswrench posted:

Thanks for the backup, Percy. Although I don't quite agree with the late Carroll Smith (crew chief on the winning GT-40 team) who when asked by Ford for his rating on the Pantera as a race car, stated "..It is hopeless. The rear suspension is fastened to nothing at all"... It's a bit flexy but not THAT bad.

The first time I saw a '40 suspension I was shocked and concerned. It's made of 1" square tubing  like the shade tent in my backyard from Viet Nam is.

I always thought that Smith was referring to the lack of "race" access to service a Pantera race car at the International GT level? That I would agree with in spades.

There are "signs" that there was considerable internal conflicts between Ford and Detomaso which shows, culminates, with buying, then shutting down Vignale and walking away from Detomaso as a retaliation? Smith's negative is an outlying symptom.

As far as the rear mounting goes, I have only two broken studs replaced right now (with BW's description 'cause that's how you do it) but am considering going all out and replacing them all now.

Considering my rear bar is upgraded in size, it can't reduce the stress on the studs, now I'm concerned what could happen if the studs break under hard load driving conditions or EVEN just cruising?

My "time" is normally now 3am. I just wake up sometimes in a cold sweat and start listing all of these "concerns" and don't get back to the "Playmate of the Year" until about 4am. Then she's not interested. Floated away actually. Figures?    

I need to organize my priorities better.

Thanks BW and PanteraDoug. I have carefully been ignoring any squeeking pleas from my rear sway Bar , cross member and the even crosser non adjustable upper brace-bar.

As my rear cross member looks like it was already pounded by the Kiwi artillery at Long Tan, I am seriously looking  at cutting it out and replacing it . It is pretty well stuffed .

I have seen some posts on  the rear cross member replacement process but are there recommendations specifically on the replacement and securing of recommended stud types as part of this process ?

Is there a consensus on the best adjustable upper brace bar cross member ? Before I buy four of them - all wrong ?????

Percy, as I remember it, the rear crossmember is made of several pieces of sheet metal somehow welded together. Any squeeking may be bushings, or maybe the crossmember parts moving!  Certainly a one-piece crossmember would be better. In a test done in the last century, we laid out a skid pad circle, then ran our Pantera with several swaybar sizes, all with rubber bar ends. Stock, then GTS, then 1" solid. The worst was the stock, the GTS was noticably better and the 1" aftermarket bar was similar to the stock bar! Tried the 1" bar on a GT-5 with 13" wide rear tires and got the same results. We finally decided the 1" solid bar was stiffer than the rear crossmembers, so the whole rear end was flexing during heavy cornering with that bar! Decades later, I found this was not so when using a slightly weaker hollow 1" bar.

Using rubber on the bar ends causes severe distortion of the rubber and subtracts from whatever benefits the swaybar provides. Using much stiiffer poly bushings on swaybar ends often causes the steel mount on the a-arm to flex, then crack due to lack of poly-compliance. Thats why the sphere-ball ends are such a good idea. I use them on both front and back, on the bar ends. I use poly in the middle where they act simply as slightly compliant pivot bushings.

As for the upper bay-brace, in my opinion the Hall straight adjustable bar in black steel with long ends is best at bracing if not as pretty as others. The u-shaped bracket the bar fastens to is actually a weldment, part of  the rear shock top, so a bar that has an end which protrudes far into the bracket will transfer cornering loads best. When a bar like that is inserted, the small bolts only keep it in position and the bar itself takes & transfers cornering loads to the shock, upper a-arm & rear upright. As-stock, the weldment tabs flex and with monstrously oversized stock bolt-holes, the bolts move around as well. You can see this from paint worn away around the stock bolt & nut.

I found that this type of adjustable bar can not only brace best, it can actually compensate for a rear suspension that's "settled" into excess camber! The key seems to be to NOT attempt to preload it enough to take out ALL SUBFRAME DISTORTION AT ONCE! Impatiently doing this can warp the rear body panels. My 'method' is to preload the adjustment only a little and drive the car a dozen miles or so, let it relax, then add a bit more preload the next day and drive it some more.

Continue this over a week or so until the rear wheel alignment is in the stock range, then periodically check rear camber for further distortion. Slow adjustment allows the rear alignment to be 'teased' back into good working order without bad effects. Our car had popped spot-welds and excess camber in 1998. I teased it back into zero camber over a week or so. Since then, it has not moved much. It won't perform miracles but can readjust for some settling.

bosswrench - Using a steel spreader bar to move things around like an orthodontist tightening the steel wires is really eye opening (humorous or sad?).

Perhaps Kindig has the right way - throw a proper frame under this car!

Thankyou BW - Great information and guidance!

If you're serious, one of those 'custom Fix-It-Show chassis'- Kindigs, Ring Bros or other TV builders, was priced at over $50,000 and did NOT have someone with Dallara's credentials designing it. You could wind up very poor and with a car that also handled poorly. Not for me!

Here are the top and bottom cross braces that I made, of course since I painted them.

I haven't tested them, there is still a lot of work to be done on the car before it runs.

That does not prevent the installation of the polyester container for the luggages.

Rene- can you repost the pictures - they did not come out ?

Rene

Those are some serious top and bottom braces !

In fact they are more extensive than any I have seen. They look like a triangulated truss model at the top and Vanhedral truss design at the bottom.

Have you modelled them or are they intuitive ? Regardless they should be effective!

...I have to say it! Rene, YOU are Serious about 'Frame Stiffness'-Triangulation!! You did not say if you plan to 'Race', or all this bracing is for 'the Street'. My point being...did you keep track of the Weight of Steel you added to the Rear, Entirety, of your Pantera? Looks as if it could be over 200 pounds, perhaps, closer to 300*, added to the rear. IMO this does not 'Improve' very well, towards  the cornering/handling response. NOT trying to piss anybody off...just bringing this to the equation.

* That's equivalent to having TWO People, Permanently laying in the Engine Bay!

Great Work, though!

MJ

P.S. ...Quote: Ferruccio Lamborghini..."Weight is the Enemy!". Although I HAVE added vendor sold cross-members, I am constantly 'weight-stripping' My Pantera. I have Her down to around 2700 Pounds or even less. Started 21 Years ago...exchanging the 20 Pound Cast-Iron Waterpump, for a  8 Pound Aluminum. Good-Luck getting Your Pantera back on the Road!! Your in for a Lot of Fun!

The so-called double brace is likely more effective than the stock one but the upper bar still attaches and transmits loads only thru stock sheet metal tabs & bolts. All are hand-made and the engineering problem I see is, the lower brackets attach to a compound-curved surface on the face of sheet metal inner rear fenders. Because the brackets only attach to sheet metal, at least 1/4" thick steel is normally used for stiffness. Forming such thick steel to a compound curve so it can be properly welded or brazed to the fender panels is a lot of metal pounding, and preload adjustments with 4 heim joints are more complicated.

Thee was a third type produced in very small numbers for awhile, consisting of two 3" or 4" thick shaped triangular carbon-fiber parts that completely filled the area between the two inner fender panels, from the upper tabs all the way down to the subframe rails. There was a threaded clevis between the two shaped parts. Rather elaborate and showy- I don't remember now who built them- but no tech article was done and I never heard anything about how well it worked. There are a few photos in the POCA Archives somewhere.

I did not model anything, I am too old for that, and therefore totally intuitive according to what I learned 50 years ago on the decomposition and the transmission of the constraints.

This is for street use, but when I saw the cracks including in the pewter trim in the corners of the engine compartment opening, near the lights, I thought it was all there openness that needed to be strengthened.
200 or 300 pounds ...... I think there is one zero too many; i'm not at home but I will weigh the top brace which is taken apart when I get home, I think it weighs less than 10kg, these are just tubes. The rear cross member is a bit heavier, but it is located very low and that lowers the center of gravity.

I like light cars a lot, I have a 1996 TVR Griffith 500 (1050 kg and 300 HP) and a Westfield replica of Lotus Seven (Collin Chapman said "light is right")  (620kg and 190 HP), but they don't have a big all-cast American V8. Just by replacing the original cast iron intake manifold with an aluminum Blue Thunder and the cast iron water pump with an aluminum one, I had to compensate for the weight of the reinforcements.

The anchor points welded to the thin sheet are positioned exactly opposite the reinforcing "side members" located in the wheel arches on the other side of the sheet, the forces will therefore be transmitted to the structure and obviously not to simple plate sheets that have no resistance.

Thanks Rene- some real inventive innovation shown here!

I came back home and weighed the top triple reinforcement: 6kg
So even though the bottom taverse is twice as heavy, that's 40 pounds in total.

Edit: I estimated the weight of the bottom rail from the dimensions of the different pieces of steel used and it is around 9kg, owe around 30 pounds for the total of the top brace and bottom rail