The owner of this car was recently at Watkins Glen. Then he noticed something wrong with the handling and with the toe of the left rear tire at his last autocross. By the time the car was unloaded at my shop this is what he was driving with.

what kind of bushings are behind there?
new nylon lock washer and big ass washer, delrin? stock?

There is rust inside the console but rust isn't the cause of the failure. Only the front half of the crack is rusty on the edge, the rear is freshly torn near full thickness metal. I have seen the exact same thing several times now. A section of spot welds wasn't done with the correct power settings on the machinery in the Karmann plant. When the car is pushed to the limit of adhesion repeatedly on modern tires the overworked inner face of the console begins to crack and eventually cannot withstand the amount of force applied and fails completely. If the factory spotwelds were done properly this never would have happened. OTOH, if the car was never autocrossed and DE'ed on sticky tires this never would have happened either.

I think they are Elephant Racing bushings.

OMG! That is NASTY! I cant believe the spotwelds seperated right along the seam there.. P.S. Did you get my PM??

New Factory console NOS is $950.00 Some left in Germany.
CCLINTORNBETWEENTWOEARS

Holy Moly! P.S. did you get my PM craig?

Obviously this is due to the stainless steel brake lines.

look familiar?
patch on my ear, extends up to the engine shelf and only to the seams. Very thick guage sheet metal.
no rust on the console as far as I've been able to tell after a good cleaning

So what can be done on our cars to prevent this from happening?
I am currently putting a v8 car together and don't want to deal with this a few years after I start driving the car, especially since I can deal with it now....

For strengthing ideas check patrick motorsports in their gallery. One of their cars, I think its silver or gray has a pice of sheet metal welded on the inner part of the dog ear with a hole for the nut.

Reinforce the area (with thicker steel)

Brace the inner ear with a tube extending to the firewall GT style (again with a reinforcement plate)

Seam weld

I'm sure there are more methods, but these are a few options.


just my free advice

I tore 2 of these (both right hand sides) in approximately 12 months time

I now am a firm believer in bracing.

Not trying to hijack Chris' thread.
he knows this and has his own expert system.

Here are pictures of my bracing on car #2:

and from below:

This is on top of my list this winter.


KT

This is definately a job for SUPERCHRIS!

My car just had a removable brace installed similar to Brant's. I don't have a pic as it's still in the shop. I also have a bar going from the rear of the suspension ear to the tranny mount structural member, plus two more at the top of the shock tower rear to the tranny mount brace and forward to the roll cage. All the work was done by TRE. Here are a few pics that show some of the bracing but not the removable one like Brants

Hey Brandt:

I see you've got the bracing on the inner ear and a link on the outside ear as well. Do you consider the link from the outter mount point to the long as part of the suspension console strengthening or is that strictly to maintain a toe setting?

Regards,
Kevin

its really just to lock in the toe setting.

but amazingly enough it flexes some also.
I had the bolt come loose on me once last season
car actually felt a little off.
we came in and started to go over it to see why.
found all 3 of the swingarm adjusment bolts still tight.
but then found the toe adjustment mounting point bolt (front one) loose.

was surprised it made a difference.
I think there is a tiny bit of extra flex that is taken out.

if you want to read about flex...
check out Chris' swing arm flex thread..
wow... amazing stuff

(thanks again for doing all of that unpaid research Chris!)

brant

Brant,

I always enjoy seeing photos of you car. You and your Dad did a great job. That is the kind of work that I wished I could do. But, I have a question about your suspension console bracing. In the photo above looving down into the engine bay the attachment point at the suspension console appears to be a flat strap with ears attached for the brace to the firewall. I have wondered why this strap was used and not boxed in to the console. As seen in the photo it looks as if it could flex, especially when the brace is in compression. Just wondering.

Thanks Mike,

regarding the strap.
its really a heavy guage piece.
I suppose it could flex, but its pretty thick.

part of the reason for the strap was to move the bar outboard.
it provides more space for the -6
and also structurally straightens out the angle to a stronger one.

On my -4 (no current picture of its brace) the similar bolt in brace goes from the inboard bolt to the firewall with out this "strap piece"

The strap piece is version #2 and was an update by my race shop. He installed the version #1 on my -4 cylinder car about 10 years back.

He felt that this was a better design, I think mostly because the brace bar is going nearly straight forward.

brant

Believe me, that strap WILL flex. If the huge boxed-section trailing arm flexes under those loads, a flat bar is going to flex, too. The arm will limit the flex to some degree, but having the arm directly attached to the ear would be a far stronger option (lighter, too). As always, there are practical considerations, and moving the parts outboard to make room for the engine is one of them.

All the bracing in the trunk does nothing for chassis rigidity. The chassis doesn't flex that way. You should run bracing in line from the firewall to the strut and to the inner suspension ear. Also a brace between the frame rails at the firewall, struts and below the engine will make a difference.

Hey Drew365:

What the heck is the thing that I circled in blue? What's it attached too,...,...?

Regards,
Kevin

I took a look across the engine compartment and here's what I saw.

bottom side detail

Repairs to the driver's side are underway.
I cut off a portion of the inner ear and found several more non-fused spot welds.

This piece had some perf but it is a lot easier to repair than replace.
The inner reinforcing layer was still good but the outer layer was badly rusted along the crack and around the bottom edge of the trailing arm mounting surface.
All the perf is filled with weld and the cracked area cut away.
This can be rewelded onto the car after just a little clean up.

Back on the car...
I pushed the lower portion back into place and welded it up along the forward pinch weld flange.
I also cut away the rusted area near the crack.
The next step is to wire brush the inside and coat with POR 15 before welding the small piece back on.

After the repair is complete I will be welding on these reinfofcing pieces.
I also plan to make similar pieces available for others to reinforce this often overstressed part of the rear suspension.

Chris looks like you are doing a great job!!! Its scary to think I was over 100mph in that car days earlier!!!! I will try to call later today didn't want to interupt you.

When the inside is coated with por15 can it be welded through or do you leave the area to be welded un-painted?

If I will be doing any welding nearby I don't put POR15 any closer than about 1/2" from the weld zone. I am using 3M Weld thru coating spray on all the weld zones and self etching primer in a can on all the exposed bare metal surfaces after cleanup.

any updates?

When I was looking for a race car, I found a fairly nice one that had a torn ear. I pointed it out to the owner who.... um .... look surprized. He had been at California Speedway the weekend before and figured that happened up on the oval.

He wouldn't take any off of the price though..... I bought another car.

What I dont understand:

Who installed the PolyBronze stuff and DIDNT inspect EVERYTHING while under the car? There is NO way this occured in one day.

Every time I'm under a 914 I clean the ears off enough to inspect them.



B

Brad,
With the engine in place and with all the undercoating on this car it would be very difficult to pick this up in advance of failure. Maybe on the passenger side it might have been found because there is definite perforation visible on close inspection.

The number of un-bonded spot welds means the console flexed more in cornering than normal. That led to failure at the most highly stressed location. I bet the crack only started to propagate late last season.

I got the inner portion of the ear welded back on but didn't have time to make the patch piece for the rusted out segment. Hopefully I can finish the drivers side and get the pass. side done, reinstall the engine and align the car for next Saturday.

I made good progress today.
Here's the console with patch installed, ground down and coated with weld-thru spray.

After that I added the reinforcing piece.

Here's the outside view.
After a coat of black paint I can reinstall the trailing arm.

I had a chance to cut into the passenger side.
This is as far as I am going to open it up as the rest seems solid enough.
At least the spot welds on the pinch weld seam appear to be holding up on this side.

This is the only other spot I opened up.
2 small patches and the reinforcing piece will take care of it, at least until the car goes under the knife for hell hole repairs.

Chris,

What gage sheet metal do you use for those reinforcement pieces?

16 ga?

They are 16 ga., approximately .057"
The console material behind the reinforcement is about .050" thick.
I'm thinking I should get 100 of the pieces waterjet cut very soon. I plan on using this reinforcement from now on whenever I am working in that area of a customer's car.

The material you use is not zink coated? This would cause problems with welding and it is not as strong correct?

Almost any time I have to work with a zinc plated part I remove the coating at least in the weld zone before attempting any welding. When the plating melts into a weld puddle it vaporizes and causes blobs of molten steel to pop out of the puddle. Not only that, zinc oxide vapors are bad for you.
Some repair panels I have used seemed to have a very thin layer of zinc and it wasn't much different than using weld thru coating.

Dr. Chris, what did you use to open up the ear? Very nice work.

maybe a stupid comment, but, don't you think a brighter/lighter paint would make it easier in the future to spot fine cracks earlier?

Andy

Hmmm... I'm so very afraid to look at my suspension consoles when I drop my engine later on... If they're good, I'm grinding an angle on the seams and running a solid bead across all of them that I can access. The last thing I want is a torn suspension console on the road, or worse -- on the track.

Very nice work Chris, and those reinforcement pieces look like they cure many ailments.

A) not gonna crack anymore
B ) A thick layer of undercoating was hiding the old cracks
C) the black paint blends in with the surrounding undercoat
D) cracks will show up just fine on a black background