Sway bar mount - welding question

[OldSpool87]

Really two questions for the folks that have welded in new sway bar mounts:

1. How did you get down to bare metal on the chassis? Wire brush on drill, grinding disc, etc

2. How should I think about the chassis metal thickness as it relates to settings on my MIG machine.

Any other pointers welcome.

Appreciate it.

[PeteKz]

I just scrape the undercoating off with a paint scraper, screwdriver, whatever works for you, and that will also scrape off the primer underneath. You don't need a lot of bare metal to get a good weld, and once you start your bead, the welding heat will burn off anything left on the surface. The hard part is the limited space you have to work in.

[winders]

The hard part is that there is crappy weak metal there and just welding in a standard factory style mount will lead to the same problem down the road....

[OldSpool87]

Originally Posted by winders

The hard part is that there is crappy weak metal there and just welding in a standard factory style mount will lead to the same problem down the road....

Right. I’m looking at the JWE mounts and waiting to hear back from them.

[OldSpool87]

Originally Posted by PeteKz

I just scrape the undercoating off with a paint scraper, screwdriver, whatever works for you, and that will also scrape off the primer underneath. You don't need a lot of bare metal to get a good weld, and once you start your bead, the welding heat will burn off anything left on the surface. The hard part is the limited space you have to work in.

Thanks Pete. Any suggestions on wire size? .030?

[Cory M]

A scotch brite paint stripping disk on a grinder works good to remove the paint and undercoating without thinning out the metal significantly. If you are welding in the cast Wevo mounts aim the nozzle to direct the heat into the mount to reduce the risk of burning through. If they are factory style mounts make and add the little reinforcement plates (search for info). I've replaced these mounts on a few cars and they weld pretty easily. Body shops disconnect the battery and ECU when welding on the chassis.

[pampadori]

one of these on a pneumatic die grinder wil get into the crevasses and quickly strip away the paint and coatings leaving bare metal.

[911 SLANT]

Thanks Winders. I've had to sets of rear brackets rip off. I will try the torsion tube way with my 20mm Tarett rear sway bar.

[PeteKz]

Originally Posted by OldSpool87

Thanks Pete. Any suggestions on wire size? .030?

I think I have .025 stainless steel wire in my MIG welder, using CO2/Argon mixed gas. I'll check it tomorrow.

And instead of cutting off the old bracket to weld on a new one, I used a piece of 4130 .0625" plate I had laying around to make a trapezoid brace that I formed to go on the inside of the original bracket. I bent the bottom edge into an "L" so that it overlapped the bottom of the existing brace. Then I welded the top of the brace to the top of the existing bracket, and tacked it onto the bottom face where the bolts attach the U-bracket to mount the sway bar.

[famoroso]

Originally Posted by 911 SLANT

Thanks Winders. I've had to sets of rear brackets rip off. I will try the torsion tube way with my 20mm Tarett rear sway bar.

Got link to "the torsion tube way?"

[winders]

Originally Posted by famoroso

Got link to "the torsion tube way?"

https://forums.pelicanparts.com/porsche-911-technical-forum/930952-welding-rear-sway-bar-mounts.html

[famoroso]

Originally Posted by winders

https://forums.pelicanparts.com/porsche-911-technical-forum/930952-welding-rear-sway-bar-mounts.html

So (unless I missed it in that thread) not commercially available off the shelf anywhere?

Thx

[winders]

Wow! I haven’t looked in about 8 years…maybe you could do your own research.

[911 SLANT]

I found them on FVD Brombacher for 175.00 each.

[stownsen914]

If you weld, do clean down to bare metal. I use a wire wheel usually, but scotch brite and other similar products will work well I'm sure. While a welder will burn through the crud probably, that same crud will become part of your weld as impurities. For welding lawn furniture I wouldn't care. but for car suspension I do.

Re: wire size, I forget what you're welding to in this case, so I speak generically. If you are welding to sheet metal .060" or less, I'd go with .023" to avoid burning through. You can use .030" if you know what you're doing, it's just trickier.

You don't mention how much welding experience you have. If this happens to be one of your first projects, you may wish to practice on some scraps you don't care about before welding your car. And I'll assume you've done your reading on how to protect sensitive electronics in the car while welding on it.

[rokemester]

I used Elephant sway bar mounts. I’m fortunate to have a pro welder for a friend who came to my garage to weld up the mounts. He had me drill multiple holes in the mounts to add more welding surface area. A clever approach I wouldn’t have considered.





I prepped the area with a wire wheel to get down to bare metal.

[PeteKz]

Originally Posted by PeteKz

I think I have .025 stainless steel wire in my MIG welder, using CO2/Argon mixed gas. I'll check it tomorrow.

And instead of cutting off the old bracket to weld on a new one, I used a piece of 4130 .0625" plate I had laying around to make a trapezoid brace that I formed to go on the inside of the original bracket. I bent the bottom edge into an "L" so that it overlapped the bottom of the existing brace. Then I welded the top of the brace to the top of the existing bracket, and tacked it onto the bottom face where the bolts attach the U-bracket to mount the sway bar.

I checked, and I am using .023 SS wire in my MIG welder. I could increase the wire size for most of my work.

[famoroso]

Originally Posted by winders

Wow! I haven’t looked in about 8 years…maybe you could do your own research.

Sorry, didn't realize you were on your period.

Originally Posted by 911 SLANT

I found them on FVD Brombacher for 175.00 each.

Thank YOU! 🙌🏻

As luck would have it, I have a package from FVD en route rn. Who doesn't like paying shipping twice. So it goes.

[AlBackus36]

Here are some surgery pictures that shows some of the sheet metal build-up on my '87. Not sure what thk changes happened over the years, but this car was two sheets of approx 0.025 thick material. It's not much. My car had been repaired twice with OE or the upgraded OE style brackets. Both broke for the PO. After the sheet metal repair I went with Tarrett's brackets.

There is a heat tube in there!





My humble opinion: The Tarrett solution is the only solution that seems to solve the problem with the G and earlier 911 rear suspension design: The rear sway bar bracket will become overloaded over time as the spring plate or trailing arm bushings wear/sag. The Tarrett plate attaches to both the inbd/outbd sides of the body here and the torque tube which will prevent localized overloading of the thin sheet metal with a face only attachment.




To prevent over loading, look into adjustable end links. On a street car, the bar should be neutral at normally loaded ride height. The OE set length end links prevent this as the car ages and the bushings sag. The end links will begin picking up more load as the spring plate bushings change and the distance between the trailing arm and sway bar mount shortens. As the load on the end link increases, the chances of the sway bar bracket breaking or attempting to tear off increase.

[Duc Hunter]

Mine are going in soon. I find a good Afro wheel is the best thing to I get the grease, undercoating, and paint off. Good body guys use them by the ton. LOL