Discreet chassis brace?

You are going to get varying opinions on this but my observation is that cars that have been stripped down to metal, then reprimed and repainted are very susceptible to cracks in all of the know stress points.

The first one to appear on mine was in the curved opening of the roof where the decklid mounts.

The problem is the car sat with it's brand new fresh paint in the garage all winter and was never driven. You can't prove to me it was from vibration stress through the skin.

Where you are indicating cracking is another area where the paint will just crack all by itself and look like a stress crack.

The other area where the paint will crack all by itself is at the base of the windshield post and the intersection of the front fender.

My wife was the first to notice it was just the cars with the new paint. The original beaters had no cracks.

Makes me wonder if there is some flex agent mixed into the original paint?

Interesting observations Doug.

There is a lower brace, I'm not sure anyone sells it as a single piece rather than as part of a kit though. It bolts up where the a arms bolt through the chassis, this is Hall's kit.

http://hallpantera.com/cgi-bin...ntera-inc&item=22697

Julian

... the areas in question all have LEAD or some composition of ... my observation is this could really be the culprit and how those areas were prepared for paint ... the so called areas which were lead don't take paint well ... were those areas rewelded before paint and did they replace the lead with a flexible body filler ?

But the answer to Adams question from what I have seen the lower 4 point brace the vendors sell appeared to be down low not in conflict with the trunk tub ... I guess another option is to install the braces and slightly alter the tub ... probably can get one cheap enough to alter.

Ron

quote:

Originally posted by accobra:
... the areas in question all have LEAD or some composition of ... my observation is this could really be the culprit and how those areas were prepared for paint ... the so called areas which were lead don't take paint well ... were those areas rewelded before paint and did they replace the lead with a flexible body filler ?

But the answer to Adams question from what I have seen the lower 4 point brace the vendors sell appeared to be down low not in conflict with the trunk tub ... I guess another option is to install the braces and slightly alter the tub ... probably can get one cheap enough to alter.

Ron

In my case, no, the seems were fine. In fact mine were brazed and then leaded over, by the factory, not me.

I was taught that brazing was preferred to welding on sheet steel. It takes less heat and thus less warping of the steel, the sheet steel doesn't need the additional strength of a weld, and it reworks much easier.

The only advantage to using lead is that it normally doesn't need to be redone when you strip the paint and primer for a redo.

People also have the misconception that lead eliminates the need for plastic body filler over it. That is not true. You still need to use some plastic over the lead to get the contours correct.

People also think that there is something magical about "today's plastic fillers". It is really the same stuff as far as the epoxy used in it. What varies is you have a choice of what the base filler is.

The basic filler is still gypsum or if you prefer, talcum powder. The better fillers use metal such as aluminum particles in it under the theory that they are more stable and more closely follow the expansion and contraction of the metal body of the car.

There are some that have additional "reinforcements" added to it like fiberglass fibers. Don't bother with those. Those types of fibers don't reinforce anything.

None of that really matters in the long run. Even the factory leaded joints will be bumpy after 20 or 30 years.

What really is better now is the primer/filler that is used now under 2 stage paints because it uses it's own hardner, is less microscopically porus and expands and contracts better.

In my view, none of this really matters anyway. The paint finish still is going to only have a life span of 20 years, plus or minus, and I have gotten more then that out of the "California Laquer" 40 coat paint I was taught to do long ago...around the time that the 20 mule team was still pulling the Borax wagons.

There exists a few distinct areas which I observe different issues with the seams on the Pantera.

The front windshield pillar top and bottom and the rear area around the tail lights ... I observed the need for additional steel reinforcement and treatment of the lead with attention to the preparation of the surface before paint. The area up top near the rear deck lid ... I stripped that area and it was welded so treatment of the lead with attention to the preparation of the surface before paint only.

The adhesion of paint to 70% lead 30% tin issues are mostly because the process requires oils and flux and the surface oxides quickly when shaping it. Lead was used in areas where the filler would exceed 1/8 or 1/4". Prep for paint requires acid cleaner then etching primer and a skim coat of polyester epoxy filler then a few coats of fill and sand primer then paint which today's Urethane's seem to be plenty flexible. It just takes some special attention to these areas. EASTWOOD summarizes the preparation very well. They recommend changing the lead to lead free solder .. also you were stating your car sat in the garage after paint and not sure if Adams is out there hammering the car to incurr heavy body flex ... so if its not a structural flexing ... maybe its the surface preparation for paint over these areas ?

Maybe some of the others can also shed some light on what they experienced ?

When stripped down, my car showed no signs of cracking through the joints in the sheet metal. Just "surface prep" was used to clean it.

I'm not disagreeing that the car couldn't use more bracing at all. Seems like a good idea and a relatively low cost solution, but a solution if it is body flex causing the cracking in the paint?

All I'm saying is that I'm not completely convinced of that and there is other prima facia evidence I have seen that tends to disagree with me.

I have a couple of cars where on the painted bumper covers the paint is cracking and peeling and it is two stage and done with the manufacturers recommendations.

It is better then 1970's paint but I must remind you that the original Pantera paint was PPG acrylic enamel and it flexes better then both the current paints and the acrylic lacquer.

I tend to think that is the reason the cars tend not to crack until they get repainted?

I wouldn't have a clue what Detomaso painted the post Ford cars with at all.

If Adams is hammering on the car...good for him, but better tires, shocks and stiffer springs as well as poly urethane bushings etc, all contribute to the cracking issues.

Something 1970's cars never even considered having consequences.

Wow, great input folks.

Seems like the Upper Rear part of the Hall kit would do it, but...

Appears it comes only in the full kit. Hmm. Emailed them to see if it was available separately

This year, the Pantera is owed a little love. Shocks (Koni old school would be fun) and the chassis kit would be great additions.

Pantera Parts Connection sells their lower front and rear braces system together and separately

Just went to their site (which shows last update as February 2012) and all links/pages are dead. Do they have another site listed differently than 'panteraparts.com'?

Not sure what's up with the site. I usually see his adds on the POCA Profiles and Quarterlies so I'm pretty sure he's still around.

I would call Larry directly to make an inquiry.

Contact info from his site:

PPC - Pantera Parts Connection
550 Mallory Way
Carson City, NV 89701
(775) 283-4400
(800) 475-2214
FAX (775) 283-4410

I guess the moral to our story is I don't think stiffeners alone are the solution to the cracking problem ... would you agree ?

quote:

Originally posted by accobra:
I guess the moral to our story is I don't think stiffeners alone are the solution to the cracking problem ... would you agree ?

If you are asking me, yes I agree with your comment. Bracing alone will not fix the paint cracking.

It never ceases to amaze me how special the Pantera really is. Even the paint needs special considerations.

Hall Pantera sells their braces separately.
Will

quote:

Originally posted by A Hudson:
Wow, great input folks.

Seems like the Upper Rear part of the Hall kit would do it, but...

Appears it comes only in the full kit. Hmm. Emailed them to see if it was available separately

This year, the Pantera is owed a little love. Shocks (Koni old school would be fun) and the chassis kit would be great additions.

I am interested in buying the lower front and rear rigidity frames. Buy the set from Hall and sell me the lower frames! Let me know.

I had cracking in all those typical spots. The cracks got bigger and bigger until I finally put those braces on. They haven't gotten any worse since I did it 10 years ago. I suggest uppers AND lowers.

Doug's cracked because of the earth quakes we have in NY ! LOL sorry had to add that little bit of humor. ..

Doug,

You have a private message. Hope it helps.

Corey

The solution to the Pantera is additional bracing plus a paint that adds structural strength to the skin without adding weight.

There you go wiz kids. Invent that.

Ron I have documentation on the Pantera cracks on about a dozen cars. All were repaints, stripped to the skin.

More likely the fireworks here rather then an earthquake caused mine, or sitting in the car late at night in the garage after having all that chili?

Only my opinion, but body cracking in Panteras comes from body flexing, usually from the stress of oversized tires and/or rough roads. The only Panteras that don't seem to crack their paint are those that have been completely seam-welded, and the windshield posts need doublers welded in top and bottom. All the cracks start in areas that are overlapped and spot-welded; with age and extra stress from cornering hard, the spot-welds pop loose. I've found several areas on several Panteras where the spot-welds were no longer connecting panels. That said, the chassis braces do seem to help but since our cars are essentially one piece, adding only part of the bracing systems, then waiting for cracking to appear in another area is doing it the hard way...

quote:

Originally posted by Bosswrench:
That said, the chassis braces do seem to help but since our cars are essentially one piece, adding only part of the bracing systems, then waiting for cracking to appear in another area is doing it the hard way...

Aha, the 'weakest link' syndrome. Makes sense.

My hopes are the bracing will bring THIS link up to greater strength equality. We'll see, and though the upgrade isn't free, it doesn't seem it can hurt the car.

Replying to my own post with Hall's response via Tara - "YES" they do sell the upper brace kit separately:

http://hallpantera.com/cgi-bin...ntera-inc&item=22695

Hudson, I think you need the brace for the shock tower that is two piece (upper and lower) that has the diagonal pieces. What you posted will do no more than the original brace. There are many discussions on this subject about the pockets needing a brace that butts against the tower pockets themselves.

The link below is to the Hall site showing their kit, the lower brace is what will help box the rear frame area.

http://hallpantera.com/cgi-bin...ntera-inc&item=22697

Also from my personal experience with fiberglass body panels that flex a lot more than any metal body part, if you use a good body filler with fiberglass reinforcement bits as a base filler and top coat with normal plastic fillers you shouldn't get cracking in the paint, but I guess it depends on the paint and the flex additives used. My body panels were sprayed the old Dupont Cantari Enamels with hardners and got no cracking on a McLaren CanAm car. Those bodies were very flexible. There are also additives that we put in the paint that allowed for more flexing which was put on the nose piece of the car that help prevent rock chipping. Current paint that goes on the plastic bumper covers on todays cars has to have big time flex additives because you can push and pull on most any bumper today and to a point they don't crack.