Samstag, 17. Februar 2018

Front strut issues resolved, once and for all!

Today we finally found the issue with the front struts! After countless strip down and reassembly sessions of the front struts, we found the mistake - which I made during assembly! When you go back to the beginnings of this blog, you might find this picture - the root of all evil!
In an attempt to do only the best for my new shock absorber cartridges, I used an "old trick" and filled the strut with oil to cool the strut... BIG mistake!!!!
The trick was used in the olden days, when oil pressured shocks were used. The Bilstein inserts are gas filled cartridges. There is a valve in the bottom of the cartridge which "breathes", depending on the movements of the shock absorber. Now, what happened and how did I found out?
When I took the strut apart today, I told my buddy to be careful, cause the strut is oil filled. When we poured the oil, it was almost nothing left of the initial 100 ml I inserted, maybe 10 ml only?

Then I tried to compress the cartridge all the way to full droop. I was irritated by the fact that it only worked about half way, then was totally blocked...
Here is the reason why, the valve basically sucked in all the oil, which then acted like a hard stop. So, the strut actually bottomed out on every pot hole and gave a harsh impact to the body!
Then we inserted the cartridge upside down in a bench press and tried to gently push the oil out:
after a while it started to bleed, then we gradually added more pressure:
You can see the oil pour down alongside the piston rod! Slowly but surely, it all drained out - but: is this thing still in perfect order, after all that oil ran through it's gutts? I wasn't convinced, so a trip to Mittelmotor was required to buy another pair of inserts, this time B6 Sport - a hair stiffer than the standard B6.
Interestingly enough, on the left strut the oil was still in the strut - I don't know if this insert wasn't o.k. and for whatever reason the valve didn't work - or maybe it wasn't that much stressed, as most of the pot holes are on the right side of the street. Nevertheless, we exchanged both struts.
Now, finally everything works well. I hope it stays this way. Happy days!

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