Hey guys im about to go to bed, ive been driving my 6 today for the first time and ive been getting a clunk coming from the shock region on both sides of the car when i go over certin bumps, not all the time, just bigger bumps... I think i may have put the bumpstops on the rear b/c im an idiot, corrrect me if im wrong but with bilstein sports no rubber bumpstops are needed on the front or the rear b/c they are internal or already built "into" the shock correct?

If this is correct then ive found my problem and it will be a quick fix....im tired, i cant find anything online, if anyone knows the answer to this please enlighten me so i can attend to the matter at hand.

thanks guys for your help!!

:stickoutt

EDIT: Both of the rear shocks/struts...

i did not put bump stops on the front b/c i knew they were built in, i think i may have put rears on...

from what i understand bumpstops are still needed on the rear because it is a shock , while struts have it bult in because it is a shock reversed?

thats all i know but from what ive been told the rears still need bumpstops

Bump stops should be on front and rear I am pretty sure "95%" Bilstiens or any other, they keep the suspension from bottoming on hard hits.

I am pretty sure the bump stop is internal on the Bilsteins used on our cars. At least for the sport and HD; I am not sure about the touring.

i guess i should call bilstein? or Bav Auto?

Talk to Bilstein.

Here is a sketch showing the mono tube design that they use compared to a conventional twin tube design. Notice the bump stop in the bottom of the Bilstein mono tube.

http://www.bilstein.com/ART/tubedesigns.gif


Here is a link to the description of their design:

http://www.bilstein.com/tech.php?PHPSESSID=275d353b6a52807ade9b7b60afae338 7

It says right in the Bilstein installation instructions that no external bump stops are needed on the front strut inserts. The rears are standard shocks and take them.

thanks man, im not at home at the moment so i couldnt look, and i havent been in the shop in a week

I am pretty sure the bump stop is internal on the Bilsteins used on our cars. At least for the sport and HD; I am not sure about the touring. My Alpina Bilstein Sport suspension on my 80 Euro uses external bump stops on both the front & rear as does the M 6 Bilstein HD suspension on my M6. I know that the Bump stops are part of the designed damping/spring rate on the Alpina Suspension. I am assuming that they are part of the design on the M6 also. It is number 10 in the diagram.

There are no external bump stops on the bilstien fronts. Even if you look at the generic drawings shown on realoem you will see this. Find the part # for parts # 10,11 or 16 for the m635. If you look at the part # list it is not shown because it is not used. The Bilstein shaft is much larger diameter that the standard shaft because it is actually the body. It will not fit the factory bumpstops.

look at parts list:

http://www.realoem.com/bmw/showparts.do?model=5531&mospid=47202&btnr=31_0079&hg=31&fg=10

This is the next page and shows what is used with the Bilstein:

http://www.realoem.com/bmw/diagrams/m/i/5.png

Lint to the page above with the parts list and drawing:

http://www.realoem.com/bmw/showparts.do?model=5531&mospid=47202&btnr=31_0118&hg=31&fg=10

Lint to the page above with the parts list and drawing:

http://www.realoem.com/bmw/showparts.do?model=5531&mospid=47202&btnr=31_0118&hg=31&fg=10
Try a 12/86 build M6 and you will see this below the diagram I posted above of the sports suspension. Since I own both an E12 and a M6 I can verify that the exterior bump stops are used on both of them. I cannot speak to every 6 made, only an 80 Euro and an 87 M6.

I have seen/had the early e24s that came from the euro dealers that had the Alpina kits installed and one had all of the Alpina parts, except the front struts were original BMW. I thought that maybe something had happened and they were changed out. I did not have good service records for the car and just passed it off as accident replacement as the bumper had also been repainted. I bought another just after this that also had the same Alpina parts less the front struts. All other parts were there and I had full records on this car that made no mention to anything being changed. Later I bought another that had the complete Alpina Kits and included the struts. :dunno

My B9 is also original and it uses the corrugated boot on the front strut like is found on other Bilsteins. And yes Alpina uses tuned suspension components with shocks and springs utilizing bump stops, but the front ones are internal. I can show pics and part diagrams from Alpina if that is necessary.

The 87 euro is listed as I has mentioned and uses the true Bilstein mono tube design. Is the 87 US M6 a true Bilstein monotube design? I dont think it is because it also uses the same bumpstop that is found on the standard 633/635.

Bilstein made some components for BMW that were different than the standard aftermarket components. Like the rears that were used on some models that were not adjustable. The euro m635 and M5 used components different than the ones available for the US market and they used the monotube design. Another reason that I prefer the euro m to the US m. Sway bars were also different on some of the US models.

Anyway, no need to argue, I make brakes for a living and many know more about BMWs than I do. Call Haygood or Bilstein and get the correct answer.

Since I own both an E12 and a M6 I can verify that the exterior bump stops are used on both of them. I cannot speak to every 6 made, only an 80 Euro and an 87 M6.

Absolutely CORRECT!

The 87 euro is listed as I has mentioned and uses the true Bilstein mono tube design. Is the 87 US M6 a true Bilstein monotube design? I dont think it is because it also uses the same bumpstop that is found on the standard 633/635.
I think you may have hit on the difference. The Euro may have a different strut assembly. I have had my M6 apart and the insert is defiantly a Bilstein. But I would never try to guess what BMW does on models destined for different markets. For instance the NA models distributed to NE USA may have an additional 1/2" of ride height as opposed to cars destined for the western part of the country. But not even then can you be sure until you disassemble the actual suspension and determine if the spacers were installed or left out. BTW if installed, they reside just below the upper spring mount. In any case, it seems that the external bump stops were not consistently employed.:) I now interpret the Shop manual a little differently. Where it says replace the rubber damper if necessary. I used to think it meant if worn, but in light of this thread I now interpret it to mean "if installed on your car"

Bilstein made some components for BMW that were different than the standard aftermarket components. Like the rears that were used on some models that were not adjustable. The euro m635 and M5 used components different than the ones available for the US market and they used the monotube design. Another reason that I prefer the euro m to the US m. Sway bars were also different on some of the US models.

Anyway, no need to argue, I make brakes for a living and many know more about BMWs than I do. Call Haygood or Bilstein and get the correct answer.
Having just upgraded the stock M6 front 21MM and rear 16MM sway bars to the M5's 25MM/18MM sway bars I can attest to the many differences.

There are so many inconsistancies with these cars from market to market (mainly US) that it is hard to say across the the board that something is one way or another. Realoem is a great tool but it can also further complicate things at times. My experiance is mainly with euro cars and I have not had my hands on many E24s past 86 so I find something new all the time.

I have done a tradeshow in the UK several times and was across from the Bilstein booth and had a chance to talk with them quite a bit (my main dealer there was a rebuilder for them which provided the opportunity). I was told that many of the factory BMW/Bilstein shocks were not rebuildable which would explain some differences.

Try a 12/86 build M6 and you will see this below the diagram I posted above of the sports suspension. Since I own both an E12 and a M6 I can verify that the exterior bump stops are used on both of them. I cannot speak to every 6 made, only an 80 Euro and an 87 M6.

I need to replace the item number 10 on my 89 csi, I thought they were bump stops but it looks like I better ask for additional shocks LOL :lol

when i installed bilsteins on mine, i did put bumpers on the rears. on the front the piston diameter is nearly as wide as the strut tube. never seen any bumpers listed. it also said not to put a bumper on, as it's already built into the strut.