Firstfives.org

[T.Hanson]

Why wave washers ? What do they do, all thin and puny, besides crack in half.

Really nuts, BMW parts lists say 49 cents each or more. Half hearted Google finds a bag of 100 for a few bucks.

Two duck plates removed show the bolts deform them. My foggy engineering solution is more washer around the bolt to spread out the smashing, wondering why the BMW gang chose thin little wave washers.

Not to mention the odd O ring, with no torque specs anywhere.

[Mike W.]

I can see their use on aluminum where a split lock washer might tear it up, and BMW does use some on steel/cast iron, but that's about it. Cheaper than a locknut and it does provide some locking action?

Torque on the duck plate is wrist tight.

My torque settings (except things like heads and rods) are as follows

6MM Wrist tight
8MM forearm tight
10MM full arm tight
12MM put your shoulder into it tight
14MM As tight as I can get it without a cheater or impact wrench.


_________________
Mike W.



1980 528i, 3.5 euro, 5 speed conversion
1981 528i, 3.6, Recaros and more. Project
1998 328is, quick and efficient, but not satisfying
2000 528iit, Vacation mobile/wife's grocery getter

[1st 5er]

[T.Hanson]

The aluminum ( surface ) explanation sounds logical. As the duck plate is steel and you like blue thread locker, puny wave washers appear to be one option, with others plausible.

I have lists of torque numbers but I like yours as a hedge for not having to thumb through books. One caveat, could you translate to snug plus a quarter turn, or half turn, three quarter ?

My wrist may be skinnier, or I'm foggy on if my hips must remain parallel to the perpendicular while rotating forearm, or shoulder may not be assisted by legs, etc.