Replacing front struts this weekend

[Mike G]

I like this diagram, pictures of your set up will help. Is your upper spring perch mushroomed in the middle?

[tomjensen]

Thanks! I’m missing the two large diameter washers. Could that be causing it to bind? Not sure if the tops have mushroomed. I’ll know when I get it back apart.


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[tomjensen]

No, if all four washers are the same, then those could all be large diameter washers and the washer under the nuts are missing.


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[Jimmy]

22 minutes ago, Mike G said:

I like this diagram, pictures of your set up will help. Is your upper spring perch mushroomed in the middle?

 

According to the drawing, shouldn't number 3 in the photo be over between 5 and 6?

[halboyles]

These are the pieces that BMW now offers for this assembly.  They are slightly different than the original parts.The second pic is of those pieces in the order they are assembled.

[tomjensen]

I might as well get all new washers and start over.


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[tomjensen]

Figured it out. If you leave out the large diameter washer that goes between the top of the spring top and the cupped washer, the strut bearing will bind with each other. The bearing won’t turn.


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[0257]

Extending this post: as part of an overall suspension refresh I am installing H&R springs front and rear.  On lowering the struts outside the front wheel wells and detaching the strut bearings, I found that the washer configuration was thus: 

 

1.  Cap nut and sleeve above and inside the top of the bearing — think of the below as an exploded diagram, with the bearing upside down on the floor and the sleeve just above it, and the nut just above that.

 

2. Below the bearing and above the spring cap, the two oversize washers and (still inside the bearing) the concave grease-catching washer/dust cap.

 

That’s all there was.  No dustcap or washer on the top at all, just sleeve and nut.  And an extra washer below the bearing, both those washers being much bigger than the washer shown as below the bearing in Halboyles’s photo above.  Steering and ride were fine, no binding or noise, no damage to concave washer.  Based on this string and the blue book this ain’t right.  Looks like I need up top to add the OBS washer (31331118095 under the sleeve and the silver washer (07119905829) above the sleeve and under the nut, and below I just need to make a judgment about whether two washers are needed, unless there’s a general opinion that the larger washers are not appropriate for some reason.

Second observation: I have what appear to be Bilstein strut inserts inside the original Boge tubes (Western Germany!) , but the only identifiers are some numbers on the blue sleeve (which can be bought separately, so I don’t trust it) and a number on the gland nut (B30-627 A1), which doesn’t correspond to any Bilstein numbers I have found on the web.  I suppose this could just be the part number of the gland nut?  Trying to identify the strut without removing it from the tube.  I am certain it is relatively new in any event, say not much more than 5 years old.  Clean and in excellent conditions.  Any guesses as to what it is based on these clues?

[irdave]

8 hours ago, 0257 said:

...

Trying to identify the strut without removing it from the tube.

 

Why not just unscrew the gland nut and pull it out?  There's nothing more to it than that...

[AustrianVespaGuy]

Pull the dust cover off and check at the very top of the piston shaft.  At least that's where a pair of old Bilstein Sports I had sported their part number stampings:

[0257]

13 hours ago, irdave said:

 

Why not just unscrew the gland nut and pull it out?  There's nothing more to it than that...

Thanks, Dave.  And thanks to lots of posts on the topic, I kind of knew that already.  But like so many other things related to 45 year old cars with multiple POs and mechanics (including Edd China), that’s a highly theoretical suggestion, and the reality is potentially fraught with innumerable rabbit trails to hell.  Right now the ride is excellent and firm, and there’s enough else to worry about — any opnion on the missing/wrong washers?