Rear Shocks, Springs and Sway bar install

[Bwana]

The saga continues.....

I took the rear shock out, no big deal there. Simply take the covers off the fenders in the trunk and unbolt the shock from both ends. I had spported the axle first though because I don't know if the shock limits the downward travel of the suspension.

However, I found this after I removed the shock and load plates

From above

From below

Somehow I don't think it should look like this. I'm suprised a bit though because it looks like the metal "broke" away as opposed to rusting thru. So can this be repaired in place without taking apart the whole rear section of the car? Should I put the old stuff back in or continue with the new springs and shocks and let the repair shop take them back out? I've not checked the other side yet, stay tuned.

Also, do I just let off on the jack to drop the suspension and replace the spring?

 

[sfdon]

I for one am very interested in seeing what was attached to the top of the strut.

 

[bmw art car]

I for one am very interested in seeing what was attached to the top of the strut.

...probably a strut bar.
i've seen this kind of damage before, the structural integrity of the shock tower mounts are pretty weak and compression/rebound forces on the shock pull right through the material.
i would get reinforcement plates welded in. i know they are out there for many BMW, don't know about E9 though.
nothing too dramatic...

 

[sfdon]

Am I the only one to notice the missing piece outline looks like the map of Texas?

Coincidence that Bwana is FROM Texas?

Hmmmmmmmm

 

[Bwana]

OK, I "Googled" the forum and found this

http://www.e9coupe.com/forum/showpost.php?p=11228&postcount=4

Looks like what I need to do. 61Porshce suggested the same over the phone.

As far as what I pulled out, this is it.

Here are the plates on either side of the shock mount

Upper shock, notice the rubber donut

Notice the taper at the end of the shock, just below the threads

Assembled. The body mount area goes between the plates

Here yo can see where the taper on the shock bolt matches up with the relief on the plate.

No metal bits though. It appears that the PO replaced the shocks but didn't repair the mount. Or the metal bits that broke off just fell out.

Off to Ace Hardware for some plate! Gonna be tough to get behind the mount area near the back seats.

 

[30csl]

Did you have any knocking from that area of the car going over bumps?

As mentioned its a common problem and is fatigue related.

I'd be happy you have found it and can get at it. Perhaps get onto a local specialist and they might come to you to repair it???
Best of luck, Rohan

 

[Bill Riblett]

The metal at the top of the shock tower fatigued over time and someone did a very crude repair. This problem was fairly common in the 80s, as reported in the paper CS Register newsletters.

Some people suspected aftermarket shocks were the cause, but it seemed like it was sort of random.

In cases where the problem was detected early, you could sometimes just weld the fracture cracks. More often, a large (approx. 3" diameter) washer was welded in place. Sometimes a second washer was welded on the other side of the broken are so there was support both above and below the original metal.

 

[Bwana]

Right side different

Here's what I found, looks like the PO tried to re-inforce it

Two AL plates sandwiching the shock dome. Look to be some sort of aftermarket thing

And the "usual damage" on the shock tower

Wonder if the three small holes are the stress points where the cracks begin?

With any luck, we're going to have a mini-coupe get together on Monday where Jerry said he'd help with welding up the towers.

 

[bmw art car]

yes, welding two large disks on both sides of the shock tower would be my approach to this.

 

[61porsche]

Shocking! Rear Metal Strut repair

1. 1/4" plate.
2. Scrap tacked over that nasty torn hole with pilot hole for 3" hole saw.
3. Drilled from below ...or above if you're fortunate to have an angle drill.
4. Same hole saw for repair piece.
5. Held from below with you're favorite shaped piece of 1 by 3, etc.
6. Welded from above in the nice inside edge you made with the hole saw.

Cleaned and painted your choice.

 

[Bwana]

Plates

So I ground off the offending parts of the shock tower so they are flat now

And made a plate out of 1/8" steel, roughly the same size as the Al plate that was in the original assembly (one for each side)

Hopefully with some magic welding, this should be stronger than the original. I didn't go with the hole saw thing as suggested by 61porsche because there was no center left to center up the hole saw. This should work. We'll see tomorrow

 

[Bwana]

Success!

All installed. 61porsche and John came over on Monday and helped me out. 61porsche did the welding, John got breakfast, tools, and re-checked the installation instructions while we were jammed under the car.

THANKS GUYS!!!!

Here's 61porsche in action, painting the shock towers after he had finished welding the plates on

The finished product. The globbed up part is the silicon sealant 61porsche packed in around the weld to keep it from rusting. It will all be covered up with the trunk skins.

Getting the lower shock mount on to the stud on the suspension was an exercise in "get a bigger hammer". It WILL fit, you just have to be motivated.

The car rides GREAT! A little softer than my wife's 540i with the M suspension but just right! I got the rubber bushing for the top of the shock from NAPA, it's some sort of "motor mount". I cut it in half, thinking about the "usual width" of a shock bumper. Big mistake, I'm going back tomorrow and get two more and put the full thickness (3/4") on to the top of the shocks.

Job done!

 

[bmw art car]

great job guys

what i noticed is...
usually people don't decorate the trunk they are laying in
:mrgreen::mrgreen:

 

[61porsche]

Interior trunk redesign

We were just trying to be festive for the labor day holiday! Actually we were experiencing the bad weather from the storm that passed south and trying to get as much done before the worst of it hit.

 

[30csl]

shock repair

One side of my coupe is repaired with a plate and three bolts holding it to the strut top. The other side had a repair washer and im tempted to try three bolts and some structural sealer under the washer. Anyone like me who can't weld tried this?
Thanks, Rohan