Rear Shock question

CookeD

CookeD

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Hey Group,

I'm doing a little suspension work, and have a question about the Bilstein shocks that are currently available.

The new shocks seem to have the threaded part (that attaches to the shock tower on the body) a bit longer than my ancient Bilsteins that I'm replacing. Specifically, the little rubber protective boot that you put back on when you're done will not fit over the length of the threaded rod once installed, as the nut is down too far on the tower.

It doesn't seem to pose a functional issue, but I'm wondering if this correct and just the way the new shocks are, or if I am doing something wrong?

Thanks in advance...
 
I installed new Bilsteins about 5 years ago, same issue. You could always trim the threaded rod, but I just left off the caps.
 
I have a set of ST sport sprongs installed, and have the same issue.

I did have some light contact between the protruding threaded shaft and my rear deck speaker magnets- is it safe to just cut the shaft lower?
 
You can't cut the shaft because the end contains the hex head that is used to hold the shaft while the nut is turned to tighten / loosen the shock against the shock tower.
 
I have run into this issue with Konis on a car other than an E9. I guess the manufacturers are making "universal" shocks, with a threaded ends long enough to accommodate a variety of models.

My solution was to put a stack of fender washers on the underside of the shock tower to bias the shock absorber downward. Unless your car is severely lowered, the shock shouldn't reach full compression when the axle hits its stops. So, moving it down 3/16 - 1/4" shouldn't make much difference (check this - don't take my word for it).

With the washers between the rubber bumper and the underside of the shock tower, the part of the stud that protrudes above the upper bumper should be about the same length as it was with the vintage shock.
 
Okay, just got the idea that I'd really like to have my trunk look not-messed-with and good, so that means covering up the aforementioned shock rods that currently protrude into the trunk (that you get with new Bilsteins).

I have the old Bilsteins that came out of the car; they're not in bad shape, and are the type that have two nuts butted together to lock the shock down onto the tower. So, no more protruding into my precious trunk, and will allow re-install of OEM looking rubber shock booties.

Bilstein will re-build these shocks for a reasonable price, so I'm wondering if anyone has had this done, and what the results were.

TIA,

John
 
Bilstein rebuild

I think I paid ~$65 each for rebuilding the rears on my 5 series last Spring, + shipping both ways. The only reason why I did it was to get them valved to Dinan specs to match the springs. Timing wise, you're at the whim of Mr. Bilstein-shock-rebuilder. I would figure 4 weeks +/-. Shocks come back working as new.

You may also want to re-inforce your back shock towers. Some folks weld (I've heard glueing also) in a washer to spread out the load at the top of the tower.
 
Hey Tod,

Thanks for the heads-up. Since I have the other shocks in, I guess I can wait, but the guy said 10 day turn-around. Maybe wishful thinking...

One nice thing about the old shock is that it has a much more substantial washer on both sides of the bushings, which is just another reason I'd like to go back to it. The towers look great so I'm hoping not to have to weld anything back there, but you never know.

Take care, and hopefully see you soon!

John
 
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