Oil in trailing arm

[BadM535i]

I am not sure what the rubber plug is for on the rear trailing arm but while heating up the trailing arm, the plug popped out and oil started to gush out.

Is there suppose to be oil inside the trailing arm?

[Rich Euro M5]

In the old days of aviation, aircraft fuselages were often manufactured from welded chrome moly tubing. After welding they were often flushed with linseed oil to inhibit corrosion on the inside of the tubing. BMW might have been using the same processes on the trailing arms.

Does the oil smell kind of like latex paint ? If so, it's probably linseed oil, also called Flaxseed oil.

Rich

[BadM535i]

No wonder it smelled weird! wow thats amazing!! Germans are truly the best engineers! I would have never known the purpose of that! After I get these powder coated, Now I know what to fill them up with!

Thanks a lot for the info!

[Coldswede]

Well, they didn't "Fill them up" with the oil they just filled them up and drained 90% of the oil out, the remainder clung to the interior of the assembly and slowly congealed into a semi solid coating, when you heated it it remelted and ran out. Just kinda of pour a quart in there and slosh it around a bit and pour out the excess

[BadM535i]

Thanks for the info, that sounds perfect!

[Shawn D.]

It's probably not even necessary to replace what ran out. Don't bother.

[a]

This is the 2nd reference I've come across regarding using linseed oil for rust inhibiting. I'm gonna try it

[Bimmerguy2002]

This is the 2nd reference I've come across regarding using linseed oil for rust inhibiting. I'm gonna try it

Your boy spasticdwarf could do the same.

Interesting though, i always thought they were empty inside-learn something new every day.

[DMNaskale]

In the old days of aviation, aircraft fuselages were often manufactured from welded chrome moly tubing. After welding they were often flushed with linseed oil to inhibit corrosion on the inside of the tubing. BMW might have been using the same processes on the trailing arms.

Does the oil smell kind of like latex paint ? If so, it's probably linseed oil, also called Flaxseed oil.

Rich

I used that stuff in the frame tubes of my old Trek 970 mountain bike frame, it was built from a True Temper OX3 cromo tubeset. Still looks good, although it was retired long ago.