Front shocks replacement procedure...

[Toga]

Good morning gentlemen,
in the process of rebuilding my restored 2002Tii, I'm now facing the unexpected: reading the BMW technical CD on how to replace a shock absorber on the front axel they write: "Add fresh engine oil¹) before installing the new shock absorber." ... ... I went through the specification and do not find anything about it. To be perfectly clear, at one place they're talking about how to renew a shock absrber that you can dismantle and they explain how and with which oil. But here it seems we have to fill some engine oil in the spring strut tube?!? I've never done that on any car. Can somebody put some light on this? Is there an anti corrosion purpose or something else? How much oil would you put in there?
Thanks fro your help and have a great day!

 

 

 

 

Edited June 5, 2020 by Toga
erase 1 picture

[dlacey]

The original shock was a rebuildable open design where the piston(s) run directly in the strut tube. BMW might be telling you to add oil as the hydraulic fluid in the tube. Replacement inserts do away with all of the original "guts" of the strut tube with the non-rebuildable insert package. There's some merit in adding a little oil into the strut tube before the insert is placed...it helps thermal conduction cooling of a hard working shock and it helps prevent the insert rusting in the strut tube - which can make it impossible to remove 20yrs later.

Edited June 5, 2020 by dlacey

[Stevenc22]

Yeah besides maybe helping slide the cyclinder in and out of the strut tube, no oil required. Just twist off the top, slide out the old gas strut (Sometimes easier said than done) and then slide in a new one and close the strut tube. 

 

The most tricky pay is the special washers under the strut hat which go in a specific order and are easy to loose.

[Toga]

Thank you guys! You just confirmed my thinking. Thanks a lot. here below my occupation this afternoon: rebuilding the pedal box...a nice jigshaw;-)

[TobyB]

If it's a Bilstone inverted damper (large shaft coming out of the top)

just a bit of any anti- corrosive is a good idea.  Coating the insert works.

 

If it's a standard damper (small shaft, less than 18mm)

then enough anti- corrosive oil to cover most of the body

will aid in dissipating heat. 

How much does it help?

"Some"

 

t

 

[tomphot]

I just did this - getting the old inserts out was a giant hassle.  One slid out with vise grips and some tapping, the other needed 2 people, table jaws and a large mallet to get it out.  There a good bit of rust holding it in.  Took a lot of cleaning the ID of the strut to get the new ones to go in.  I can understand the suggestion of adding some oil to the sides of the strut and letting some settle to the bottom to prevent corrosion.  A future owner will thank you when they need to get them out at some time.

[Toga]

Thanks again!  I'll definitely add some oil there!
It seems I was quite fortunate with mines as they came out quite easily but there was a quite disgusting mixture in there that probably helped.
Take care.

JP